True Science

Natural science and the Catholic faith have two different ends, although they are not mutually exclusive. One is to understand the physical world, God's creation, and the other is to know God directly. St. Thomas Aquinas, a medieval doctor of the Church whose best works treat the relationship between science and faith, says in his Summa Theologica Iª q. 1 a. 5 s. c., in response to the question "Whether sacred doctrine is nobler than other sciences?", that "Other sciences [e.g., the natural sciences] are called the handmaidens of this one [i.e., theology, sacred doctrine]: 'Wisdom sent her maids to invite to the tower' (Prov. 9:3)." Although sciences besides the study of sacred doctrine are subordinate to the Catholic faith, this in no way relegates them. Pope Pius IX and Pope Pius X were very pro-science; they saw how the errors of modernism not only threatened the Catholic faith but also threatened true science, too. They condemned these two propositions, respectively: Catholicism is compatible with modern civilization (Syllabus of Errors, 80.) and Catholicism is incompatible with true science (Lamentabili Sane, 65.); hence, modern civilization and true science are incompatible. But why are modern civilization and true science incompatible? Firstly, modern civilization is opposed to the Church. The huge popularity of anti-Catholic entertainment attests to this:

Is there anything science can't do? Evidently not. Here is Brown at his wackiest (p. 658): "Science has come to save us from our sickness, hunger, and pain! Behold science-the new God of endless miracles, omnipotent and benevolent! Ignore the weapons and the chaos." It's even an elixir for personal problems: "Forget the fractured loneliness and endless peril. Science is here!" The fact is that Catholicism promoted science & astronomy: Science would not have progressed as it has. "For the last fifty years," says professor Thomas E. Woods, Jr., "virtually all historians of science...have concluded that the Scientific Revolution was indebted to the Church." Sociologist Rodney Stark argues that the reason why science arose in Europe, and nowhere else, is because of Catholicism. "It is instructive that China, Islam, India, ancient Greece, and Rome all had a highly developed alchemy. But only in Europe did alchemy develop into chemistry. By the same token, many societies developed elaborate systems of astrology, but only in Europe did astrology lead to astronomy". The Catholic role in pioneering astronomy is not questioned. J.L. Heilborn of the University of California at Berkeley writes that "The Roman Catholic Church gave more financial aid and social support to the study of astronomy for over six centuries, from the recovery of ancient learning during the late Middle Ages into the Enlightenment than any other, and, probably, all other institutions." The Jesuits scientific achievements alone, reached every corner of the earth. What was it about Catholicism that made it so science-friendly, and why did science take root in Europe and not some place else? Stark knows why: "Because Christianity depicted God as a rational, responsive, dependable, and omnipotent being, and the universe as his personal creation. The natural world was thus understood to have a rational, lawful, stable structure, waiting (indeed, inviting) human comprehension."

—Joseph Dias

Secondly, many believe modern science is more universal than the Church and try to arrive at a purer religion that everyone, regardless of their beliefs, can understand and accept. Pope Pius X condemns this as "broad and liberal Protestantism" (Lamentabili Sane, 65.). Lastly, modern civilization asserts there is no absolute, objective truth and reality: relativism. Modernism and relativism are big issues impeding some from coming to the Catholic faith, as encyclicals like Pope St. Pius X's Pascendi Dominici Gregis and Pope Pius XII's Humani Generis show. The Berkeley philosopher John Searle proves very well, and solely in philosophical terms, the irrationality of relativism in his "Refutation of Relativism" paper. The argument basically runs thus: "You can't even state relativism without denying it." Resulting from relativism is the notion that all the world's religions can coexist, i.e., syncretism, which is atheistic. It assumes the gods of the various religions do not exist in reality because if they all did exist, and because there are contradictions between the gods of different religions, there would be a contradiction in reality. Consequently, there would not be one truth but chaos, contradicting half-truths, and irrationality. Reality, however, is sensible and rational; not only can the natural sciences attest to this, but so can the Catholic faith, too. Read, e.g., Pope Benedict XVI's Epiphany '09 homily and his philosophy of mathematics. If there is no absolute truth or one single God governing the universe, then all religions' gods are only figments of their individual adherents' imaginations. That gods are whatever one wants them to be is Luther's Protestant idea that everyone is his own authority or even his own god, i.e., sola fide or "faith only" in any god(s). This is why Pope Pius X condems "broad and liberal Protestantism" in Lamentabili Sane. In summary, only with an increase of virtue and morals in today's civilization, resulting from a return to the Catholic Church, can true science progress.

Physics: A Holistic Perspective

My friend wrote the following; it's an excellent summary of modern physics from a Catholic perspective. Homeschoolers would also benefit from it because of the summary questions at the end:

I. The Nature of Physical Science

A. Truth, Opinion, Science, and Faith

Before commencing the study of any subject matter, one ought to know its definition, scope, and methods. We must therefore examine the nature of physics, both in itself, and in relation to other branches of study. Let us attempt to understand it by first defining what we mean by “science.”

Physics is one among many different sciences. Today, when we say “science,” we usually mean one of the physical sciences. But that is simply a prejudice of the modern mind. “Science” is derived from the Latin “scientia,” which means “knowledge.” This clearly distinguishes it from technology, which is an application of this knowledge to the practical needs of life. Truth is the correspondence between our judgments and reality. Truth does not lie in our ideas, but in the affirmations and denials we make with those ideas. If our judgment about the world accurately reflects reality, then we call it a true judgment; otherwise, we call it a false judgment. Opinion can therefore in some sense be called “knowledge,” inasmuch as some opinions are indeed true. So what distinguishes science from true opinion?

We are often correct in our assertions about the world, but cannot say why. We cannot give a reasoned account of our knowledge. We merely have true opinions. Science, then, to distinguish it from true opinion, is defined as “knowledge through causes.” That is to say, if we know the causes (or reasons) for something, then we understand what it is and how it behaves in varying circumstance. If we remove the causes, then we necessarily remove these behaviors, and perhaps even the thing itself. In this way we have added to our true opinion a reasoned account of our knowledge. Naturally, some events cannot even in principle be the subject of human science. Any contingent event, that is, any event that may or may not occur in a fixed set of circumstances, cannot be the subject of a science. For instance, since human will is free to choose, one cannot prove or predict its acts. For if the will were determined by the circumstance in which it must choose, it would cease to be free. One consequence then of “rationalism” (the false opinion that all reality is subject to human science) is that free will is denied. God, by way of comparison, does have knowledge of these “future contingents,” for it is God Who moves our wills directly. In like manner, history cannot be a human science, because its course is not governed solely by material factors, but by human beings acting freely. In general, if the causes of anything are inaccessible to our human intellects, that thing cannot be the subject of a human science.

A question that will naturally occur to students concerns the place of the Catholic Faith: Is their act of faith merely true opinion, science, or something else entirely? For the theological modernist, faith is an opinion that answers to nothing objective, but to the subjective needs of men. In other words, it is even less than true opinion. It is opinion that corresponds not to a single reality, but to the desires of many different believers, which can be and usually are contradictory. This modernist conception of faith is utterly false, but before we examine the true nature of faith, we ought to consider why the modern world has taken refuge in this empty notion. It is clear that faith cannot be the same as science, because we do not know the causes of much that is comprehended under faith. There are two reasons for this. First, many articles of the Faith concern contingent events: the fall of man, the Incarnation, the Redemption, and many others. These belong properly to the study of salvation history, and depend upon not only the free choices of creatures, but the absolute freedom of the Creator. Second, some of the articles of faith transcend our human capacities of rational demonstration. Examples here must include the doctrine of the Trinity and the miracles performed by Christ. At this point the modernist goes wrong, because he is really a rationalist. Logically speaking, if the whole universe is knowable by human science, and human science has no way of evaluating the articles of faith, these articles must not correspond to anything in reality. These false friends of religion therefore seek some substitute for objective reality. All that remains to them is their subjective consciousness, so they set up a correspondence between faith and subjective feeling instead. Faith for the modernist is not about the world “out there” (reality), but about the world “in here” (feeling). Consequently authentic religion is for the modernist not a life in conformity with the Divine Will, but one in conformity with personal longings.

If, however, we are honest about the limits of human reason, our humility will lead us to a better account of the act of faith and, through this act of faith, to a more profound understanding of God and the universe of beings created by God. The Catholic Faith, which makes dogmatic claims about reality that can and often do conflict with faulty claims of human science, is most certainly true in every respect. Such claims as conflict with the Catholic Faith are not really science at all, or even true opinion. They are falsehoods. But what allows us to profess the Faith with this absolute certainty?  What character does it have beyond true opinion? An act of faith is an act of trust in the authority of a revealer. It is an entirely reasonable and rational act if we can ascertain that the revealer both has the knowledge in question and will not deceive us.

Modern scientists ask for just such an act of faith from their pupils. The student has no way of verifying the immense number of observations and inferences that have been incorporated into modern science. He must depend upon the knowledge and veracity of his instructor, who himself depended upon another. Thus, there develops a scientific tradition (handing down) of previous observation and inference. The student, for his part, has good reason to have faith in his instructor. The instructor is likely to have credentials indicating his proficiency in the subject matter. He may have accrued many years of service at a prestigious university or scientific institution. Moreover, he would be severely penalized for deviating in essentials from that tradition. Peer reviews and academic evaluations continually guarantee that the scientist conforms to the generally accepted views of the scientific community. The instructor has few credible incentives to misrepresent physical theories to the student and will suffer serious consequences if he systematically does so. It is therefore entirely reasonable for the student to submit his mind to that of his teacher, so long as the scientist remains within the boundaries of his competence.

The act of faith that the Catholic makes is similar, but more certain and absolute, depending also upon the gift of God. First he determines, either by his own reason, by his common sense, or by following the reasoning of another, that there is a God, Who has every perfection of Being, including Truth and Goodness. These truths are sometimes called the “Preambles of the Faith,” because they are the reasonable foundation on which our act of faith depends. Now God has intervened in human history, initially by sending the prophets, but finally by sending His Eternally-Begotten Son, Jesus Christ, born into time of the Blessed Virgin Mary. By His public miracles and especially by His Resurrection from the dead, He has proven His Divinity. We may therefore conclude two things: First, as perfect Truth, Christ has knowledge of all things created and uncreated. Second, as perfect Goodness, He can have no desire to deceive us and wills only the good. His Doctrine is therefore true in all details and best calculated for the good of those who will receive it. We cannot pick and choose which doctrines to believe, but are obliged to assent to Revelation in its entirety because of the Authority of the Revealer. To assure that the Tradition (handing down) of the Faith is maintained until the end of time, He established a visible Church that is One, Holy, Catholic, and Apostolic.

Faith and science can never be in contradiction, for all truth has its ultimate source in God. But we must be careful to distinguish their relative certainties. It is science that cannot contradict Faith, and not vice-versa, for the Divine Revealer is more perfect in truth and goodness than any creature, and Christ has demonstrated His Divinity with unshakable proofs. We must reject, therefore, whatsoever we find in human doctrines that either contradicts or yields a conclusion contradicting Divine Revelation, bearing in mind always the Magisterium (Teaching Authority) of the Catholic Church.

B. Three Orders of Scientific Abstraction

Since science is “knowledge through causes,” we naturally seek to understand what is meant by causes, for we cannot use these as instruments of understanding unless we can accurately recognize and classify them. But it is important to first distinguish clearly between the three principal sciences applied to the material world: metaphysics, mathematics, and physics. In the classical and medieval traditions, these sciences study real beings, but each studies beings under a different aspect. Metaphysics is the highest of these, for it is “the science of being as being.” In saying that it is a “science of being,” we simply mean that we are studying real beings. In saying that metaphysics is “the science of being as being,” we indicate that the particular aspect under which we are studying beings is precisely their being. The first is materially what we are studying, the second is the formal aspect under which it is studied. In other words, we are studying beings just insofar as they are beings and no further. We are not interested in their particular nature, whether they are living or inert, but only what can be inferred about them from their existence. This definition will become clearer if we compare metaphysics to mathematics. Mathematics likewise studies real beings, but under the aspect of quantity. So mathematics can be defined as “the science of being as quantified.” It is concerned with beings only insofar as they can be measured. Finally, the classical and medieval traditions understand physics as “the science of being as movable.” In other words, physics considers ens mobile, which is Latin for “mobile being.”

These three sciences are traditionally understood to form a hierarchy, with metaphysics at the top, followed by mathematics, and then physics. This hierarchy corresponds to differing orders of abstraction, with physics being the least abstract, mathematics more abstract, and metaphysics the most abstract. When we say that one is more abstract than another, we do not necessarily mean that one is more complicated than another, or even more difficult, but rather that as we progress upwards, we leave out certain aspects of real beings. Let us consider a concrete example. Real material beings possess individual matter that makes each thing to be this thing and no other. For example, Socrates is individuated (made an individual) by this particular matter (these hands, this snub nose). But the human intellect can only apprehend things abstractly; there can be no science of individuals. The first abstraction is to leave out the individuality (or thisness) of the matter. What is left is matter insofar as it is sensible (able to be perceived by the senses). The study of beings under this aspect is called “physics.” Physics studies Socrates not insofar as he is Socrates, but insofar as he is a man. It pertains to a man to have matter, indeed, but not any particular matter.

When objects are studied mathematically, they are studied only insofar as their matter is intelligible, for the intellect leaves out of consideration their sensibility. When we imagine a mathematical triangle, we consider it extended in two dimensions, but this extension is only intelligible to the understanding, not perceptible to the five senses.  Likewise, when we study Socrates mathematically, we consider him only insofar as he has a measurable body. (e.g. He is 68 inches tall. He weighs 160 pounds.) Finally, metaphysics abstracts from matter entirely, for it considers only the existence of the object and any other attributes that accrue to it from that existence alone. So we consider Socrates insofar as he has being and the unity, truth, and goodness, that necessarily accompany being.

Science:	Studies:	Example:	Leaves Out:	Supplies Principles To:
metaphysics	“being as being”	Socrates as being	all matter	mathematics, physics
mathematics	“being as measurable”	Socrates as body	sensible matter	physics
physics	“being as movable”	Socrates as man	individual matter

Table I.A:  The Hierarchy of Abstraction in the Sciences

This hierarchy of abstraction among metaphysics, mathematics, and the physical sciences, is also a hierarchy of principles. A superior (more abstract) science is able to supply principles of study to its subordinate sciences. The definition of motion in physics must be taken from metaphysics, for physics cannot define its own subject matter. Likewise, physical science depends upon mathematics for its understanding of quantity, which is absolutely crucial to the study of bodies in motion. The lower science cannot supply the higher examples with principles for study, but only concrete material for the higher science to study. So physical science provides bodies to be studied mathematically, and both physical science and mathematics provide beings to be investigated by metaphysics. The principles of study descend downward from higher science to lower, while the matter to be studied ascends from lower science to higher. Before we proceed to a study of physical science, then, it is necessary to discover in metaphysics some basic principles to guide us.

C. Motion and the Four Causes

We know from experience that there is change or motion. It is inescapably part of this world. There are also many different kinds of motions. So we would do well to define motion first.

A little thought will convince the student that the task is no easy one. It is one thing to recognize motion when we see it, but to define it requires a good deal of genius, such as that possessed by Aristotle. He recognized that to define motion, we need to say something about the terms of motion, that is, the before and after of every change. Aristotle saw clearly that change is only possible when something actual is also potentially something else. For example, a piece of bronze may actually be a bust of Julius Caesar, but it is potentially a bust of Marcus Brutus, that is, if it were melted down and recast in a different shape. Before any such change takes place, there must be these two principles in a thing: First, the matter (bronze), which can potentially be given a different form. Second, the form itself (Caesar), which determines it to be this thing and no other. The bronze can potentially become many different things; we say that this matter has a potency to become all of them, but can be actually only one of them at a time. Perhaps now we can understand what is meant when it is said that “being is divided into act and potency.” These are two principles that all created beings possess, and it is in terms of them that we must define motion.

We might be tempted to say that “motion is a change from potency to act,” and we would be correct, but we would have failed to define “motion.” Why? Because we would then be required to define “change,” which, as a little thought will make clear, is really nothing more than the “motion” we set out to define. This is an example of a logical fallacy called “petitio principii,” or “begging the principle.” Motion cannot be defined as a particular kind of motion! Aristotle, on the other hand, saw that in every continuous motion the object is in varying degrees of reaching its final actuality. To return to our example, as the molten bronze is poured into the cast, it gradually assumes the form of the bust of Brutus. At each moment it is actually some particular shape on its way to becoming Brutus. Aristotle saw that something like this was happening in every continuous motion. He therefore defined “motion” as “the entelechy of a being in potency insofar as it is in potency.” This term, “entelechy,” means something close to “act,” but it also includes the idea of reaching its end. As it has come down to us through the medieval Latin tradition, motion is defined simply as “the act of a being in potency insofar as it is in potency.” In our example, the motion from Caesar to Brutus would be “the shape of the bust of Caesar which is potentially Brutus, insofar as the bust is potentially Brutus.” The potency of being Brutus lies in the bronze, not in the current shape of Caesar. In other words, it is not “the shape of the bust of Caesar which is potentially Brutus insofar as it is actually Caesar.” This shape would be its present form, the shape of Caesar’s bust. Motion is something’s act precisely in its ability to be something else, that is, just insofar as it is in potency. Philosophers may legitimately debate the merits and difficulties of such a definition, but a better one has yet to be proposed.

We are half way to understanding Aristotle’s four causes in material substances. We have already discussed two kinds of cause: the material cause and the formal cause. In our example, the material cause is the bronze which can potentially become many different shapes, and the formal cause is the shape of Caesar’s bust. These two causes, matter and form, are called “intrinsic causes” because they lie within the material substance. Both the bronze and its present shape are included in the bust itself, but two other causes do lie outside of the bust. The latter causes are therefore called “extrinsic causes.” The first of these, called the “efficient cause,” is the working of a sculptor. A bust of Caesar cannot become a bust of Brutus without an external agent (one acting) to impress upon it a new form. This agent is the efficient cause. The second, or “final cause,” is the end to which the sculpture must conform. In forming the bust of Brutus from the bronze in the bust of Caesar, there must be some standard toward which the bronze is directed. This is the ideal shape which the sculptor holds in his mind. The sculptor strives to bring the shape of the bronze into conformity with his idea. Without any one of these four causes we are unable to explain why things change.

There is another way to view these four causes. We have seen that the bust is in act insofar as it has a determined shape. The shape (form) in some sense acts upon the bronze (matter) to determine it to this one thing and no other. The form is active in relation to the matter; the matter is passive in relation to the form. Or, in other words, the form acts upon matter; the matter is acted upon by form. Now the efficient cause operates through form because it imparts form to matter. That is, it causes form to act upon matter. The final cause operates through matter because it directs the matter to its new form. That is, it causes the matter to be acted upon by form. The difference is subtle, but the efficient and final causes can be likened respectively to pushing and pulling. Whereas the efficient cause moves by action from a beginning, the final cause moves by attraction to an end.

Cause:	Location:	Example:	Causal Character:
Formal	intrinsic	shape of bust	acts upon matter
material	intrinsic	Bronze	is acted upon by form
efficient	extrinsic	action of the sculptor	causes form to act upon matter
Final	extrinsic	sculptor’s idea of the bust	causes matter to be acted upon by form

Table I.C:  The Four Causes

D. Science and Method

Clearly, the methods of each science will differ. Physical science, because it abstracts from particular matter, but not from sensible matter, can make extensive use of the senses in its demonstrations (experiments). Mathematics, having abstracted from sensible matter, cannot use sensible objects in its demonstrations (proofs). It can only use the ideal properties of bodies in intelligible matter. This does not mean that the mathematician cannot use drawings or diagrams to help him remember. It only means that the diagram, which in fact always departs from the ideal, cannot supply the principles of his demonstration. Metaphysics, having abstracted from matter entirely, cannot use either sensible objects or ideal bodies. It must use principles of pure intellect and judgment alone.

We have said already that the superior science supplies principles to the lower sciences. Metaphysics studies beings only insofar as they have being. One principle of metaphysics is the principle of non-contradiction: a thing cannot be and not be at the same time under the same aspect. Clearly, both mathematics and physical science make ample use of this metaphysical principle. But mathematics adds new principles, for instance, the postulates of Euclidean geometry, without which it would not be possible to reason about figure. Physical science, the least abstract of the three, borrows from mathematics as well as metaphysics, for without the conclusions of mathematics, the physical sciences would be unable to measure change. But it also must seek additional principles from the senses.

The modern mind calls a science only that which can be studied experimentally, that is to say, through the experience of the senses. Mathematics, abstracting from sensible matter as it does, has consequently become today an exercise in logic having no necessary connection to reality. Indeed, the attempt has been repeatedly made to resolve all of mathematics into merely logical relationships, without any recourse to imagination and its intelligible matter. Naturally, metaphysics is rejected outright by those who do not understand the orders of abstraction proper to each science, and who therefore exclude whatever does not invoke a material cause. This scientific demand is nonsense, especially where the science of revealed theology is concerned. For the various elements of Divine Revelation can serve as principles (causes) of demonstration no less than those of geometry or physics. Moreover, such theological demonstrations are more dignified inasmuch as the principles of demonstration often transcend what can be obtained by any human science.

Leaving these higher sciences aside, the experience of the senses should be an important part of method in the physical sciences. The “scientific method” is usually presented as a clear-cut, even mechanical, order of investigation. But this order does not always hold in practice. The investigations of physical science bring the whole man, with all his prejudices and experiences, inclinations and aversions, into a new relation with the physical world. Many physical discoveries have been the result of accident, blind trial and error, or sudden brilliant insight. Examining this method will, nevertheless, help the student understand an important part of the physical scientist’s work.

1.	Define a problem that requires a solution.
2.	Produce an hypothesis to explain the problem.
3.	Predict new consequences of the hypothesis
4.	Test the hypothesis experimentally.
5.	Formulate a valid theory that yields new problems.

Figure I.D: The Steps of the “Scientific Method”

First, the investigator must begin with something he wishes to explain. He produces an hypothesis (educated guess) about the causes responsible. He then predicts new consequences from the hypothesis that can be tested experimentally. The testing of these leads, in turn, to a more comprehensive theory that produces new questions or problems for the scientist. Theories that have been thoroughly tested and have attained a high degree of certainty are sometimes called “scientific laws” or “laws of nature.” The third step is truly the great advance which the moderns have made upon classical Greek science. For the ancient Greeks were keen observers, profound thinkers, and quite imaginative in their hypotheses. Yet, each one having explained some physical phenomenon to his own satisfaction, they ceased to progress. It is really no wonder if an hypothesis accounts for all present observations. That is precisely why it was formed! If it did not, it could be easily discarded. But how can one determine which of the remaining hypotheses is the best? The modern method demands not only that the hypothesis account for prior observations, as did the ancient method, but also that it yield new predictions, which can then be tested. The linear method of the Greeks has been replaced by a circular one that, if followed diligently and with intelligence, will constantly check the accuracy of our physical theories. This modern scientific method has, for both better and worse, radically transformed the intellectual and material culture of the modern world.

There remains to say a few things about experiments. An experiment is not simply a passive listening to nature; it is an active interrogation of nature. Nature cannot be allowed to speak at random, but must be made to answer the questions we put to it, which means that an experiment must be carefully conceived and executed. Prior to the experiment, we should already have an hypothesis about the causes that are operating behind the appearances. The experiment must be designed to verify or reject that hypothesis with certainty. This is what Francis Bacon called an experimentum crucis (critical experiment). The physical circumstance of the experiment will typically be an uncommon or contrived one in which the presence or absence of the these causes will be easily seen. It will very often require a physical apparatus to put nature into such a condition and scientific instruments to amplify and record the results of the experiment.

The classic example of the experimentum crucis is Sir Isaac Newton’s experiment validating his theory of color mixture. It was well known from ancient times that some transparent materials, such as raindrops and some glasses, have the power to produce all the colors of the rainbow from an initial beam of white light. Some investigators were of the opinion that white light is modified to produce these colors. Newton, on the other hand, thought white light a composition of all of the colors, and that the prism is just separating white light into its colored components. He performed a simple experiment to decide which of the hypotheses was true. He first used a glass prism to produce the whole rainbow (the visible spectrum of light) from a single beam of white light. But then he cleverly positioned another prism to take in all of the colored beams and reunite them into a single beam. If the material of the prism were really modifying the light, the second prism would either further modify the light or have no more effect on the already modified light. On the other hand, if his own hypothesis were true, the various colors would be gathered back together to form white light again. The experiment proved him correct. He could separate white light into colored components and then mix them back together again to form white light. The competing theory of color was overturned.

E. Physics and the Physical Sciences

Were we to leave off our discussion of the physical sciences here, we would be greatly deceived about the scope of modern physics. For in early modern times a great change took place in the whole conception of the physical world.

The classical physics of Aristotle regards the world as filled with various natures. For instance, there is the nature of a stone, the nature of a tree, and the nature of a horse. The first is a mineral, the second a plant, and the third an animal. The Greek “φύσις,” from which we derive the word “physics,” and the Latin “natura,” from which we derive the word “nature,” have the same basic meaning. They refer to the essence of a thing insofar as it is a principle of operation and motion. In other words, having a particular nature implies having a particular kind of operation and motion. So the inert stone has its principles of motion, the living plant another set of principles, and the sensitive animal still another set of principles. These principles of operation are understood to be embodied in the highest form of the individual substance, which is called the substantial or essential form. When the substantial form is also a principle of the operations of life, it is called a soul. So a stone has the ability to act and be acted upon through contact. In addition to these operations of lifeless matter, a plant has operations proper to its own degree of being: It can transform inert matter into living matter through growth and reproduce to form new plants. An animal adds to these operations those of the senses: touch, taste, smell, vision, and hearing, or some combination of these. So it has a more perfect operation and a more perfect being than the plant. The study of these substances reveals a hierarchy of natures in the world, with man, whose soul is both the substantial form of the body and a spiritual (non-material) substance in its own right, at the pinnacle of the material creation.

A change in thinking is evident when we consider that we no longer understand physics to be the study of natures, but the study of nature. The mechanical philosophies of the early modern period had a leveling effect. The entire universe was conceived as one vast machine with interacting material parts, all essentially inert. The difference in perfection between a living being and an inert one was reduced to a mere difference in complexity. René Descartes, the first significant proponent of this philosophy, dispensed with the souls of animals and plants, but perceiving that man possesses spiritual operations (intellect and will) that do not involve matter, he retained the human soul. The human body was an “extended substance,” the human soul a “spiritual substance.” Man had become a body accidentally united to an angel. There is no way in his philosophy to rejoin the soul and body into a single human being. Later thinkers, taking Descartes to his logical conclusion, dispensed entirely with a soul that had ceased to have any relation to the physical world: Man is a machine, a marvelously intricate one to be sure, but just a machine.

So plants, animals, and men might exhibit extraordinary complexity of structure and behavior, but they can ultimately be reduced to the mechanical interaction of their material parts. This mechanical philosophy of nature is therefore called “reductionist.” The idea of individual substance has disappeared altogether. The operations of inert matter, now understood to be universal and, even more importantly, complete descriptions of all matter, have been stripped from substantial forms and turned into “laws of nature.”  Where then do these “laws” exist? In God? Scientists of the early modern period were commonly of this frame of mind, but later agnostic and atheistic thinkers could not avail themselves of this option. Form had become nothing but a particular arrangement of matter. The only remaining option was to identify these operations with matter itself. So the leveling of reality became an inversion: Matter is the basic reality; form and spirit, so-called, are but fleeting arrangements of matter. In this way were born the pernicious doctrines of Darwinism and Marxist materialism.

Since matter is understood to be the ultimate reality, and since mathematics is able to study the arrangements of matter in bodies, the application of mathematics is central to modern physics. Whatever cannot be reduced to quantity is dismissed as incapable of scientific study. There are indeed legitimate investigations corresponding to today’s mathematical physics. In the middle ages, such sciences were called “scientiae mediae,” or “intermediary sciences.” St. Thomas Aquinas taught that these sciences have a physical subject (matter), and a mathematical aspect of study (form). Medieval examples are optics and astronomy. What is objectionable in modern physics is not that bodies should be studied mathematically, but that the philosophies and even the mathematical doctrines underlying modern physics make it exclusively mathematical. These doctrines contain a complete restructuring of the physical sciences. Modern physics considers the ultimate “laws” and material constituents of inert bodies. Other physical sciences, for their part, are considered legitimate only insofar as they are thought to be reducible to physics. In accordance with reductionist thinking, they cannot invoke principles superior to those that govern inert matter. Most striking of all, since physics now has regard only for lifeless matter, there is today neither in theory nor in practice a true science of biology! All that remains is the name.

The Catholic student must always be aware of this inversion in modern physics and cautious of its influence in his thinking. Contrary to what many Catholic apologists claim today, modern physics implies a philosophy that cannot be reconciled to the Catholic Faith, for it is false in its very principles. This is not to say that modern physics’ mathematical predictions are inaccurate, for these conform well to reality. It is not experience that is faulty, but the formulation and interpretation of experience. There remains for orthodox Catholic scientists and philosophers a task of immense scope, severe intellectual discipline, and unremitting opportunity. The physical sciences, and indeed the various branches of mathematics, must be reconceived and reordered, all the while preserving the great multitude of legitimate modern discoveries and observations. No individual or small group of individuals will suffice; this project will demand the labor of legions of talented and dedicated philosophers, theorists, experimentalists, teachers, and popular expositors. Catholic Tradition affirms that “grace builds upon nature.” With a sound philosophy of nature again in hand, the Church will find more fertile ground in which to plant the seeds of faith. Let us be sure that the credit for this is referred to God alone:

Ad Majorem Dei Gloriam.

Chapter I.A Review Questions:

1.        What is meant by “truth”?

2.        What is a “science”? How does it differ from “true opinion”?

3.        What is meant by a “contingent” event? Why cannot these be the subject of a human science?

4.        What does the theological modernist mean by “faith”?

5.        What does the orthodox Catholic believer mean by an “act of faith”?

6.        Does the scientist demand an act of faith from his student? Why?

7.        Why is the Catholic’s act of faith in Jesus Christ entirely reasonable?

8.        How must all conflicts between scientific theory and the Catholic Faith be resolved? Why?

Chapter I.B Review Questions:

1.        How are the subject matters of physics, mathematics, and metaphysics defined?

2.        What do we mean when we say that one science is more “abstract” than another?

3.        In what way do physics, mathematics, and metaphysics abstract from individual beings?

4.        Under what aspects would physics, mathematics, and metaphysics study a diamond?

5.        In what way does the hierarchy of sciences yield also a hierarchy of principles?

Chapter I.C Review Questions:

1.        What are meant by “act” and “potency”?

2.        How is “motion” defined?

3.        How does the act of motion differ from the act of form?

4.        What is the difference between an intrinsic and extrinsic cause?

5.        What are the four causes? Which are intrinsic and which extrinsic?

6.        How should we understand the difference between an efficient cause and final cause?

7.        Give an example of a motion not found in the text and identify its four causes.

Chapter I.D Review Questions:

1.        In what way does the order of abstraction of each science determine its method?

2.        Give examples of principles that physics borrows from metaphysics and mathematics.

3.        What are the five steps of the modern “scientific method”?

4.        How do the physical investigations of the modern scientists differ from those of the ancient Greeks?

5.        Why cannot the “scientific method” of the physical sciences be applied to mathematics, metaphysics, and theology?

6.        What is an experimentum crucis? What distinguishes it from mere observation of nature?

Chapter I.E Review Questions:

1.        How does the classical science of Aristotle view the world?

2.        What did the Greeks and Latins understand by the terms “φύσις” and “natura”?

3.        What is a “substantial form”? What is a “soul”?

4.        Describe the “mechanical philosophy” of nature.

5.        Describe Descartes’ philosophy of the body and soul. What is the great problem with it?

6.        How did the notion of a “law of nature” come about?

7.        In what way has modern science limited the idea of form?

8.        How do Darwinism and Marxist materialism find their justification in modern physics?

9.        Why has mathematics become so central to the modern study of the world?

10.        What are “scientiae mediae”? Give some examples.

11.        Why is there today no true science of biology?

12.        Can modern physics in its present formulation be reconciled to the Catholic Faith? Why or why not?

Relation of truth, beauty, and reason

This is a disproof that "beauty is in the eye of the beholder," which is really a statement of someone who denies objective truth, who upholds relativism. It shows the relation between truth, beauty, and reason.

Disproof

• "Truth is the equation of thought and thing." (St. Thomas Aquinas's Summa Theologica Iª q. 16 a. 1 co.)
• God is the equation* of thought, the divine intellect, and thing, His essence. 
• • ∴ God is truth. (ibid. Iª q. 16 a. 5 co.)
• "Beauty [...] consists in a certain clarity** and due proportion"† (ibid. IIª-IIae, q. 180 a. 2 ad 3).
• God is "the cause of the harmony and clarity of the universe," being its creator. (ibid. IIª-IIae, q. 145 a. 2 co.)
• • ∴ God is the cause of beauty.
  • • ∴ Truth is the cause of beauty.
• "The ancient philosophers held that the species of natural things did not proceed from any intellect, but were produced by chance‡.
• "But as they saw that truth implies relation to intellect, they were compelled to base the truth of things on their relation to our intellect.
• • ∴ "Such, however, do not follow, if we say that the truth of things consists in their relation to the divine intellect" (ibid. Iª q. 16 a. 1 ad 2), God.
  • God, Who has and is the divine intellect, exists outside of the human intellect, viz., He is objective. [St. Anselm's ontological argument: "God, being defined as most great or perfect, must exist, since a God who exists is greater than a God who does not" (New Oxford American Dictionary) and exists only in the mind.]
  • • ∴ Truth is objective.
    • • ∴ The cause of beauty is objective; ∴ beauty is objective.

* to the highest degree
** viz., truth, the 'equation of thought and thing'
† which is "found radically in the reason; because both the light that makes beauty seen, and the establishing of due proportion among things belong to reason."
‡ Chance, or randomness, has neither clarity nor due proportion; therefore, chance is opposed to both beauty and reason.

The nested syllogisms above are of the form:

• Proposition A
• Proposition B
• • ∴ Conclusion / Proposition A*, etc.

Is not it utterly amazing how truth, beauty, and reason relate to one another because of God?

Many scientists, e.g., Einstein and Dirac, thought a beautiful explanation of nature is the truest, but they have defeated themselves by failing to realize the connection—because of their often relativist, positivist, and atheist philosophical assumptions—between absolute truth and beauty, thus severing the link between these: reason.

It is no wonder that we moderns—who eschew God and a true study of God, Thomistic theology, from universities—often have little desire to seek absolute truth and beauty and often have a very primitive aesthetics, evidenced, e.g., by the current iconoclastic trends in architecture. Theology is absolutely critical to a property functioning university and true science.

After having visited Thomas Aquinas College (TAC) in Santa Paula, CA, (read their amazing founding document), I have been inspired to pursue further the idea of starting a Catholic Technical Institute (CTI), a sort of tech-biased version of the more liberal-arts–biased TAC. For further background on this sort of university and its importance to science, read Newman's Idea of a University. In a nutshell, we need a tech university that prepares future physicists, e.g., to combat both skepticism and relativism, a university that acknowledges both faith and reason as legitimate means to an absolute truth. Skepticism and the denial of an absolute truth toward which the various sciences strive renders knowledge once obtained meaningless. If there is no real connection between the objective world viewed by physicists and psychologists, e.g., then what use is knowledge in either field? Is it even knowledge or a fabrication, perhaps self-consistent but isolated in itself? This connection between the sciences is called theology, and the lack of theology in schools—especially the "perennial philosophy" of St. Thomas—is really a bigger issue than one may think.

I lay it down that all knowledge forms one whole, because its subject-matter is one; for the universe in its length and breadth is so intimately knit together, that we cannot separate off portion from portion, and operation from operation, except by a mental abstraction; and then again, as to its Creator, though He of course in His own Being is infinitely separate from it, and Theology has its departments towards which human knowledge has no relations, yet He has so implicated Himself with it, and taken it into His very bosom, by His presence in it, His providence over it, His impressions upon it, and His influences through it, that we cannot truly or fully contemplate it without in some main aspects contemplating Him. Next, sciences are the results of that mental abstraction, which I have spoken of, being the logical record of this or that aspect of the whole subject-matter of knowledge. As they all belong to one and the same circle of objects, they are one and all connected together; as they are but aspects of things, they are severally incomplete in their relation to the things themselves, though complete in their own idea and for their own respective purposes; on both accounts they at once need and subserve each other. And further, the comprehension of the bearings of one science on another, and the use of each to each, and the location and limitation and adjustment and due appreciation of them all, one with another, this belongs, I conceive, to a sort of science distinct from all of them, and in some sense a science of sciences, which is my own conception of what is meant by Philosophy, in the true sense of the word, and of a philosophical habit of mind, and which in these Discourses I shall call by that name. This is what I have to say about knowledge and philosophical knowledge generally; and now I proceed to apply it to the particular science, which has led me to draw it out.

I say, then, that the systematic omission of any one science from the catalogue prejudices the accuracy and completeness of our knowledge altogether, and that, in proportion to its importance. Not even Theology itself, though it comes from heaven, though its truths were given once for all at the first, though they are more certain on account of the Giver than those of mathematics, not even Theology, so far as it is relative to us, or is the Science of Religion, do I exclude from the law to which every mental exercise is subject, viz., from that imperfection, which ever must attend the abstract, when it would determine the concrete. Nor do I speak only of Natural Religion; for even the teaching of the Catholic Church, in certain of its aspects, that is, its religious teaching, is variously influenced by the other sciences. Not to insist on the introduction of the Aristotelic philosophy into its phraseology, its explanation of dogmas is influenced by ecclesiastical acts or events; its interpretations of prophecy are directly affected by the issues of history; its comments upon Scripture by the conclusions of the astronomer and the geologist; and its casuistical decisions by the various experience, political, social, and psychological, with which times and places are ever supplying it.

What Theology gives, it has a right to take; or rather, the interests of Truth oblige it to take. If we would not be beguiled by dreams, if we would ascertain facts as they are, then, granting Theology is a real science, we cannot exclude it, and still call ourselves philosophers. I have asserted nothing as yet as to the pre-eminent dignity of Religious Truth; I only say, if there be Religious Truth at all, we cannot shut our eyes to it without prejudice to truth of every kind, physical, metaphysical, historical, and moral; for it bears upon all truth. And thus I answer the objection with which I opened this Discourse. I supposed the question put to me by a philosopher of the day, "Why cannot you go your way, and let us go ours?" I answer, in the name of the Science of Religion, "When Newton can dispense with the metaphysician, then may you dispense with us."

[...]

Now, as far as this objection relates to any supposed opposition between secular science and divine, which is the subject on which I am at present engaged, I made a sufficient answer to it in my foregoing Discourse. In it I said, that, in order to have possession of truth at all, we must have the whole truth; and no one science, no two sciences, no one family of sciences, nay, not even all secular science, is the whole truth; that revealed truth enters to a very great extent into the province of science, philosophy, and literature, and that to put it on one side, in compliment to secular science, is simply, under colour of a compliment, to do science a great damage. I do not say that every science will be equally affected by the omission; pure mathematics will not suffer at all; chemistry will suffer less than politics, politics than history, ethics, or metaphysics; still, that the various branches of science are intimately connected with each other, and form one whole, which whole is impaired, and to an extent which it is difficult to limit, by any considerable omission of knowledge, of whatever kind, and that revealed knowledge is very far indeed from an inconsiderable department of knowledge, this I consider undeniable. As the written and unwritten word of God make up Revelation as a whole, and the written, taken by itself, is but a part of that whole, so in turn Revelation itself may be viewed as one of the constituent parts of human knowledge, considered as a whole, and its omission is the omission of one of those constituent parts. Revealed Religion furnishes facts to the other sciences, which those sciences, left to themselves, would never reach; and it invalidates apparent facts, which, left to themselves, they would imagine. Thus, in the science of history, the preservation of our race in Noah's ark is an historical fact, which history never would arrive at without Revelation; and, in the province of physiology and moral philosophy, our race's progress and perfectibility is a dream, because Revelation contradicts it, whatever may be plausibly argued in its behalf by scientific inquirers. It is not then that Catholics are afraid of human knowledge, but that they are proud of divine knowledge, and that they think the omission of any kind of knowledge whatever, human or divine, to be, as far as it goes, not knowledge, but ignorance.

—Card. John Henry Newman's Idea of a University, part 1. ch. 3 §4 & ch. 4 §1

Reason & Faith: Double-Truths?

Averroes, the prominent Islamic philosopher who said "I necessarily conclude through reason that the intellect is one in number; but I firmly hold the opposite through faith," thought that scientific truths are completely separate from and can even contradict truths not based on human reason, such as truths divinely revealed. This would seem to give science more academic freedom, being apparently unencumbered by seemingly unnecessary religious dogma. But the Islamic philosophy's decoupling of reason from religion and upholding a "double-truth" is a false philosophy with dangerous, irrational consequences, e.g., radical fundamentalism. However, science and the Catholic faith are compatible, as St. Thomas Aquinas's writings, the basis of Catholic philosophy, establish. In his De Unitate Intellectus Contra Averroistas ("On the Unity of the Intellect Against the Averroists"), the thirteenth-century St. Thomas refutes Averroes's denial of the individuality of the human intellect:

Just as all men naturally desire to know the truth [Aristotle, Metaphysics I, 1, 980a], so there is inherent in men a natural desire to avoid errors, and refute them when they are able to do so. Now among other errors, the error that seems especially inappropriate is the one concerning that very intellect through which we are meant by nature to avoid errors and know the truth. For a long time now there has been spreading among many people an error concerning the intellect, arising from the words of Averroes. He tries to assert that the intellect that Aristotle calls the possible intellect [Aristotle, De Anima III, 4, 429a 18-24], but that he himself calls by the unsuitable name "material," is a substance separate in its being from the body and not united to it in some way as its form, and furthermore that this possible intellect is one for all men. Against these views we have already written many things in the past [e.g., Summa Theologiae I, q. 76, a. 1 & 2]. But because the boldness of those who err has not ceased to strive against the truth, we will try again to write something against this same error to refute it clearly. It is not now our intention to show that the above-mentioned position is erroneous in this, that it is opposed to the truth of the Christian Faith. For this can easily enough become evident to everyone. For if we deny to men a diversity of the intellect, which alone among the parts of the soul seems to be incorruptible and immortal, it follows that after death nothing of the souls of men would remain except that single substance of intellect; and so the recompense of rewards and punishments and also their diversity would be destroyed. However, we intend to show that the above-mentioned position is no less against the principles of philosophy than against the teachings of Faith. And because, so they say, the words of the Latins on this subject have no savor for some persons, but these men say that they follow the words of the Peripatetics, whose books on this subject they have never seen, except those of Aristotle who was the founder of the Peripatetic Sect; we shall show first that the above-mentioned position is entirely opposed to his words and meaning.

—De unitate intellectus, pr.

Nowhere can the Catholic faith contradict true science or vice versa, even though there have been many accusations: (1) that of the Galileo affair, which was due to the fact that, unlike Copernicus, Galileo asserted his theory as absolutely true and not simply as a scientific theory subject to possible error, or (2) that the Church disapproves of the scientific theory of biological evolution, which is untrue; for according to Denzinger's 1911 edition of his collection of Catholic dogma, Enchiridion Symbolorum et Definitionum, the First Vatican Council states:

1797 [The impossibility of opposition between faith and reason]. But, although faith is above reason, nevertheless, between faith and reason no true dissension can ever exist, since the same God, who reveals mysteries and infuses faith, has bestowed on the human soul the light of reason; moreover, God cannot deny Himself, nor ever contradict truth with truth. But, a vain appearance of such a contradiction arises chiefly from this, that either the dogmas of faith have not been understood and interpreted according to the mind of the Church, or deceitful opinions are considered as the determinations of reason. Therefore, "every assertion contrary to the truth illuminated by faith, we define to be altogether false" [Lateran Council V, see n. 738]. 1798 Further, the Church which, together with the apostolic duty of teaching, has received the command to guard the deposit of faith, has also, from divine Providence, the right and duty of proscribing "knowledge falsely so called" [1 Tim. 6:20], "lest anyone be cheated by philosophy and vain deceit" [cf. Col. 2:8; can. 2]. Wherefore, all faithful Christians not only are forbidden to defend opinions of this sort, which are known to be contrary to the teaching of faith, especially if they have been condemned by the Church, as the legitimate conclusions of science, but they shall be altogether bound to hold them rather as errors, which present a false appearance of truth. 1799 [The mutual assistance of faith and reason, and the just freedom of science]. And, not only can faith and reason never be at variance with one another, but they also bring mutual help to each other, since right reasoning demonstrates the basis of faith and, illumined by its light, perfects the knowledge of divine things, while faith frees and protects reason from errors and provides it with manifold knowledge. Wherefore, the Church is so far from objecting to the culture of the human arts and sciences, that it aids and promotes this cultivation in many ways. For, it is not ignorant of, nor does it despise the advantages flowing therefrom into human life; nay, it confesses that, just as they have come forth from "God, the Lord of knowledge" [1 Samuel 2:3], so, if rightly handled, they lead to God by the aid of His grace. And it (the Church) does not forbid disciplines of this kind, each in its own sphere, to use its own principles and its own method; but, although recognizing this freedom, it continually warns them not to fall into errors by opposition to divine doctrine, nor, having transgressed their own proper limits, to be busy with and to disturb those matters which belong to faith.

Before a scientist might judge this as the Church's apparently being threatened by science and desperately trying to keep it "in its place," note what St. Thomas Aquinas says:

[T]he argument from authority based on human reason is the weakest, yet the argument from authority based on divine revelation is the strongest.

—Summa Theologica Iª q. 1 a. 8 ad 2

It would seem this is untrue because correct interpretation of divine revelation is difficult and subject to human error and speculation. But that human reason is subject to error is precisely the point; authority based on human reason is like building a house on sand. Compared to divine authority—authority based on the solid foundation of something most perfect, powerful, and immutable, i.e., absolute truth itself—human reason is unstable, changing, fleeting, and restrained by time. Therefore, "the argument from authority based on divine revelation is [indeed] the strongest;" and consequently science, with its roots in a true philosophy (i.e., Scholastic Thomism) that does not contradict divine revelation nor human reason but strives to understand a single absolute truth, is even stronger. This is true science.

Virtuous Technology

The Catholic faith supports true science and technology, not "science [that] should trump ideology," e.g., not "science [that] should trump the Fifth Commandment, 'Thou shalt not kill.'" Therefore, true science and technology are virtuous, pro-life, and opposing of all "homicidal research." (Bishop Olmsted "What should science trump?")

Noah was humanity's first virtuous, pro-life scientist and engineer. Receiving scientific knowledge on how to build a piece of technology, a boat, not from himself but from the Holy Spirit, Wisdom; he saved humanity from destruction due to its poor decisions.

Noe found grace before the Lord. [...] the earth was corrupted before God, and was filled with iniquity. [...] [God] said to Noe: [...] Make thee an ark of timber planks: thou shalt make little rooms in the ark, and thou shalt pitch it within and without. And thus shalt thou make it. The length of the ark shall be three hundred cubits*: the breadth of it fifty cubits, and the height of it thirty cubits. Thou shalt make a window in the ark, and in a cubit shalt thou finish the top of it: and the door of the ark thou shalt set in the side: with lower, middle chambers, and third stories shalt thou make it. Behold, I will bring the waters of a great flood upon the earth [...]

—Genesis 6:8,11,13-17

* 1 cubit ≈ 44 cm

Today, too, we face destruction due to our poor decisions regarding the sanctity of human life. Demography tells us that we are dying at an alarming rate. For example, the number of children ever born per woman living in the U.S. was 1.862 in 2006, much below the replacement level of 2.1; and 45.1% of U.S. women of fertile age have never had children (Fertility of American Women: 2006). Other countries, too, face economic problems due to aging populations, thus we are experiencing a "demographic winter." Pope Benedict XVI addresses the causes of this in his recent encyclical on economics, Caritas in Veritate.

Although there are many good research projects trying to save lives without killing other lives, there are also many that try to prevent or even kill human lives, as with contraceptive or abortifacient research, respectively. Like with Goethe's Faust, we have sold our souls for the exchange of scientific knowledge that compares very little to the greatness of Noah's science and technology, for God—"the guide of wisdom, and the director of the wise"—

hath given [us] the true knowledge of the things that are: to know the disposition of the whole world, and the virtues of the elements, the beginning, and ending, and midst of the times, the alterations of their courses, and the changes of seasons, the revolutions of the year, and the dispositions of the stars, the natures of living creatures, and rage of wild beasts, the force of winds, and reasonings of men, the diversities of plants, and the virtues of roots, and all such things as are hid, and not foreseen [...] For in [wisdom] is the spirit of understanding; holy, one, manifold, subtile, eloquent, active, undefiled, sure, sweet, loving that which is good, quick, which nothing hindereth, beneficent, gentle, kind, steadfast, assured, secure, having all power, overseeing all things, and containing all spirits: intelligible, pure, subtile.

—Wisdom of Solomon 7:15,17-23

Pro-life technology is a great application of our intellect to helping others. Just as Noah applied his intellect to designing and building a boat to save humanity, so, too, can we apply ours to technology for our greater good, not death.

Science and Modernism

Because modern science has proven very effective at explaining the physical world, some have succumbed to the error of Modernism, which is not only harmful to religion but also actually harmful to the development of a true science which can more accurately explain nature.

The cognitional theoretical basis of Modernism is agnosticism, according to which human rational cognition is limited to the world of experience. Religion, according to this theory, develops from the principle of vital immanence (immanentism) that is, from the need for God which dwells in the human soul. The truths of religion are, according to the general progress of culture, caught up in a constant substantial development (evolutionism).

—Dr. Ludwig Ott's Fundamentals of Catholic Dogma pgs. 16-17

It appears that Modernism is only the subject of religion, the dogmas of which some may think the progress of modern science threatens. Yet it relates to science, too, since even though it is true that knowledge begins in the senses—i.e., from experience—it does not end there; rather, it ends in the intellect, the human's soul, in which exists the universal knowledge that science discovers. Agnosticism nihilistically states that it is futile "to know the reality corresponding to our ultimate scientific, philosophic, and religious ideas." (Shanahan 1908); one therefore cannot be agnostic and interpret quantum mechanics, for example, except possibly with the instrumentalist interpretation. Immanentism basically says that God and religion are manifestations of man, not realities apart from man and given to him by God, respectively; and evolutionism says man's nature changes. Although science has failed to prove any of these propositions, some assume them—consciously or not—in order to remove God from science and consequently also to ignore the study of God or theology, which is the noblest science of which the "Other sciences [e.g., the natural sciences] are called the handmaidens." (Summa Theologica Iª q. 1 a. 5 s. c.).

Before discussing how Modernism leads to pathological science, let us first give some historical context and see how Modernism affected the French Catholic physicist of the "Gibbs-Duhem Equation," Pierre Duhem (1861-1916), who, interestingly, thought that all fields of physics are reducible to thermodynamics.

2. Fideism or Rational Obedience

In the encyclical Pascendi Dominici Gregis of 1907, two years after Duhem's 'Physics of a Believer', the official position was made clear in the name of Pope Pius X. Of the dangerous aspects of the heresy it called "modernism" identified by the encyclical two concern me here, what it called the "agnosticism" of the modernists, and the separation of science and faith. The first for example was dangerous because of the damage it did to natural theology:

human reason is confined entirely within the field of phenomena, that is to say, to things that are perceptible to the senses, and in the manner in which they are perceptible; it has no right and no power to transgress these limits. [...] Given these premises, all will readily perceive what becomes of Natural Theology, of the motives of credibility, of external revelation.

The second was under suspicion of fideism:

Having reached this point [...] we have sufficient material in hand to enable us to see the relations which Modernists establish between faith and science. [I]n the first place it is to be held that the object of the one is quite extraneous to and separate from the object of the other. For faith occupies itself solely with something which science declares to be unknowable for it. Hence each has a separate field assigned to it: science is entirely concerned with the reality of phenomena, into which faith does not enter at all; faith on the contrary concerns itself with the divine reality which is entirely unknown to science.

Pascendi goes on to suggest that the modernists really meant to subject faith to science but were afraid to say so, and was even to find pantheistic implications in the position. It can be assumed that one target of this passage was Alfred Loisy's attempt to separate the results of the critical analysis of Scripture from the dogmatic claims of the Catholic Church, and that another was the memory of late mediaeval and Renaissance theories of double truth, truth in philosophy separate from truth in faith; but the concern of the first passage to preserve the integrity of natural theology shows the importance of wider considerations. Duhem is not one of those identified as targets of the encyclical. Whether his work was even known to those who drafted it must be a matter of speculation. But quite apart from his explicit disapproval of the enterprise, it is hard to envisage the kind of natural theology that could be accommodated to Duhem's account of the aim and structure of physical theory.
The issue was basic, the subject even of dogmatic definition, by the First Vatican Council of 1870-71, the Council that, in non-Catholic circles at least, is more famous for the definition of Papal infallibility. That Council, using the double negatives usual in such definitions, had declared anathema anyone who should deny that the knowledge of God was accessible to human reason. Though what that meant is not easily determined, most of the bishops present must have meant to say that the knowledge of God was accessible to human demonstration, not of course that knowledge of Him contained in the creeds and dogmatic formulations of the Church, but the knowledge that there is a good God who created all things: the rest belonged to Revelation, not reason.
But whatever the bishops thought they were doing thus making the demonstrability of God's existence a matter of faith, the general strategy is clear enough: to offer the faithful what are technically known as motives of credibility, reasons that would make it rational to accept the Catholic faith and ecclesiastical authority. The faithful could be assured that, God's existence being demonstrable by reason, it was rational to accept the dogmatic formulations of the faith concerning Him offered by the church, and rational also to accept the authority of the Church that propagated this faith, rational to support the Church as it defended its temporal power against the new kings of a reunited Italy, and rational also to defend the Church in its resistance to the Prussian rulers of Germany and republican rulers of France. At the same time, of course, it turned Catholics into a disaffected element in all three states, a disaffected element the authorities had to disarm at the price of their own survival.
So it emerges that by propagating a system of physics that undermines natural theology Duhem has rendered himself suspect of the heresy (for that is the effect of the Council's decree) of fideism, the belief that the faith rests on faith and nothing else, and that conclusion was explicitly drawn by F. Mentré, one of those who wrote on Duhem's work after his death. In his eyes, Duhem's views were of no use on religion because of this fideist taint, connected with what he identified as its Pascalian sources, the subject of the next chapter. Furthermore, the counterpart of fideism is philosophical scepticism, the doubt about the reliability of knowledge of any kind, about its ultimate guarantees. Thus in 1893 Eugène Vicaire detected it Duhem's views "the poison of scepticism" and was appalled that such views should appear in a Catholic journal, the Revue des Questions Scientifiques, in which Duhem's early articles appeared.

3. The Revival of Scholasticism

But the consequences go even further, and it is here that neo-Scholasticism falls to be considered. There is no point in asserting the demonstrability of God's existence, or of anything else for that matter, unless there is available a philosophical system to do it in, just as to demonstrate God's non-existence a philosophical system, such as that provided by the various brands of positivism, was equally necessary. In 1878 the Encyclical Aeterni Patris of Leo XIII hit the nail on the head by citing St. Paul in favour of its view that 'false philosophy' was the source of the modern apostasy. The 'true philosophy' offered in its place was a revived Scholastic philosophy, the philosophy associated by the encyclical indiscriminately with Thomas Aquinas and the latter's thirteenth-century Franciscan contemporary Bonaventure, but in practice looking more to Aquinas as interpreted by such sixteenth-century commentators as Cajetan and Suarez.
The groundwork for the encyclical had been laid over the previous half-century. At least since the sixteenth century, there had always been a tendency towards Scholasticism in Catholic philosophy and theology, and corresponding difficulties with 'modern' philosophies. For example, an episode better known that some because of the attention Leibniz paid it, is the persecution of the followers of Descartes in the 1670s and 1680s because of the difficulties their philosophy created for the Eucharistic doctrine of transubstantiation defined by the sixteenth-century Council of Trent, the doctrine that at the words of consecration the substance of the bread and wine are transformed into the substance of the body and blood of Christ, leaving only the so-called accidents of colour, taste, and texture unchanged. Despite the intentions of the Fathers of the Council of Trent, this doctrine can hardly be understood outside the philosophy of substance and accident in which it is stated, still less if matter is defined, as it was by Descartes, as essentially, in substance that is, the space it occupies—and nobody suggested that that changed at the words of consecration!
Just as at the end of the nineteenth century Duhem was to turn the philosophy of positivism against the anti-religious conclusions of the positivists, so, in the early nineteenth century a serious of attempts was made, all of them resulting in condemnations for their authors, to adapt philosophies of non-Catholic origin, such as those of Kant and Schelling, for the purposes of Catholic apologetic. As interpreted by many, the problem seems to have lain in perceived violations of the balance between faith and reason demanded of Catholic orthodoxy: reason was to offer motives of credibility, to prepare the ground for faith by making credible the acceptance of a faith such as that revealed in the Scriptures and the decisions of the Councils of the Church, but not to go further. A group of Rome-based Jesuits, of whom the most prominent were Matteo Liberatore and Joseph Kleutgen, argued that only a scholastic philosophy, looking to that of Thomas Aquinas, would do, and they convinced Gioacchino Pecci, the future Pope Leo XIII, of the merits of their case.
In the Pope's mind the main object of the scholastic revival was theological, but there were at least two others: a revaluation of the thought of the Middle Ages, and of the Church's rôle in it, and indeed a re-affirmation of its value in the face of widespread denigration; and the thought that a revived Scholasticism, judiciously interpreted, might be found of use in questions of modern philosophy and science, despite prevalent expectations to the contrary. In short, by this action the Pope intended to re-affirm, against all the apparent odds, what he saw as the Church's heritage, and from that would no doubt flow improved morale among the troops confronted by a hostile world and, even, greater respect for the Church among those who did not belong to it.
The encyclical thus led to a theological programme to re-examine and restate Aquinas's 'five ways' for proving God's existence, to a historical programme to recover the mediaeval materials on which scholastic thought to contemporary questions, whether social, ethical, or scientific. These different programmes were not of course independent: the scholasticism available to the Pope had been mediated by the work of commentators at least two centuries distant from Aquinas's own time, so that a genuine revival of his thought had to go back past these to the sources, to find out what Aquinas had actually said; Aquinas's work was also apparently embedded in an obsolete natural philosophy, of generally Aristotelian character, so that if his theology was recoverable, it had in some way to be reconciled with later scientific ideas; and any application to contemporary questions had to depend on answers to the prior question of what the philosophy was that was to be applied.
The later progress of scholarship was in due course to call into question most of the answers initially given, but it is these initial answers that concern Duhem: the work of Aquinas was supposed to consist principally in the reconciliation of Christianity with Aristotle, and in the mid-twentieth century Dom David Knowles, a historian with a low opinion of the scholars of the century following Aquinas, was still presenting Aquinas's supposedly successful achievement of this goal as the crowning intellectual achievement of the Middle Ages. It was this Aristotelianism of Aquinas, and of scholastic philosophy as it was generally understood, that was perceived to be the main stumbling block in the way of a Scholastic revival, and it will be a main problem for the remainder of this essay. To the extent that Duhem was involved in neo-Scholasticism, if he was so involved, that involvement can be expected to show itself in Aristotelian themes in his work, and by a sympathetic treatment of mediaeval Aristotelianism, as well as by associations with journals with generally neo-Scholastic policies.

4. Duhem the Scholastic?

Given the obstacles to scholasticism mentioned in the previous paragraph, it is understandable that different would-be scholastics adopted different strategies to meet them. The Roman seminaries, for example, apparently maintained an integral Thomism with few compromises towards modern science, but this was hardly a serious option for a practising mathematical physicist interested in having his work taken seriously by his contemporaries. Another obvious possibility would have been to reject the whole thing root and branch, either outright, or in the manner of the Italian Agostino Gemmelli, who in 1904-05 proposed a Scholasticism that included modern thought. I believe that something like this was Duhem's final position, but it was, as will be seen, decisively rejected by Pope Pius X in his Encyclical Pascendi of 1907, and something will be said below about how Duhem got there: it is by no means obvious that outright rejection was his position when he wrote them, and his earlier reactions to Blondel seem to point the other way.
An obvious intermediate position was to try to adapt scholastic natural philosophy to make it conform to the discoveries of modern science, the position that seems to have suited the eirenic temperament of Désiré Mercier, the future Cardinal Archbishop of Malines, and his group at Louvain. This was the programme behind the Société Scientifique de Bruxelles, which Duhem seems to have joined as a lecturer at Lille, and he seems to have appreciated its attitudes and approaches enough to attempt to recruit Paul Tannery into its membership. Apart from its Annales, which published his Les Théories Électriques de J. Clerk Maxwell, its principal organ was the Revue des Questions Scientifiques, a heavyweight quarterly carrying in depth discussions of the scientific questions of the day, but intended for an educated lay audience. it was not afraid of carrying long multipart articles, and of these Duhem became a major contributor: it seems to have been his preferred place of publication for general philosophical and historical pieces throughout the 1890s. This was the journal that carried his 'Réflexions' of 1892, Vicair's critique, and Duhem's replies. One of the latter, not considered so far in this essay, seems as good a place as any to begin a consideration of Duhem's possible relation to neo-Scholasticism.
'Physique et Métaphysique' of 1893 was the first of Duhem's replies to Vicaire. It addressed the suggestion, made by more than one of Duhem's readers, that his rigourous separation of physics from metaphysics was no more than a cover for denigration of the latter: the metaphysician was free to get on with it in his corner while the Duhemian physicist got on with it in his without interference, the implication being the positivist one that physics was the only real knowledge to be had. Duhem insisted that this was not his intention. On the contrary, metaphysics was for him a genuine form of knowledge, indeed "more excellent" than physics, but separated from physics by having different objects and being governed by different methods. The Scholastic expertise with which he set out his views seems to have impressed not a few of his readers enough to make them wonder whether he had a scholastic mentor, for in the normal course of events this was not the sort of expertise a physicist could be expected to have. Be that as it may, Duhem was claiming to be classifying independent and legitimate science, not distinguishing sense from nonsense in the manner of earlier and later positivists.
Repeated in Duhem's later writings, this move has been the main source for the view that Duhem's prime philosophical inspiration was neo-Scholastic. But initially plausible as this interpretation may seem, it becomes less so when Duhem is compared with a genuine neo-Scholastic like Jacques Maritain, who did indeed distinguish his sciences, but only so that thereafter he could unite them, assign each of them its place in the overall system of the sciences, and say which sciences could and could not establish what on the foundations of which others. The basis for Maritain's scheme, as of numberless others of like provenance, is the view that some sciences can be subordinated, or sub-alternated, to others in the Aristotelian scheme of things. A science is conceived of as a deductive system of syllogisms, deduced from one or more definitions of the essences that are the subject matter of that science, and remaining within its genus or natural kind, and it is supposed that the conclusions of one science can serve as principles for another, as when the sciences of equilibria and music take their principles, as subaltern science, from the superior sciences of arithmetic and geometry. Famously, this scheme ran into difficulties with the applied mathematical sciences, such as astronomy in ancient times and terrestrial physics in modern: if Aristotle was right, natural philosophy should have been subordinate to 'physics', or, in Duhem's terminology, 'metaphysics', but the mathematical science of nature soon left Aristotelian metaphysics far behind, a point that will be considered further below.
I mention now two aspects of such schemes: they were only achieved at the price of distorting Aristotle, for whom mixed sciences would have meant mixing genera, something his methodological principles forbade; and their rationalistic atmosphere, not to say hubris, is remote indeed from a scientific world in which, as in the physics of Duhem, mathematical formulae are devised to meet the problems thrown up by experiment, not those suggested or deduced from a priori theory. The reconstruction of Aristotle that would reconcile his views to modern science would have to be pretty radical, radical both at the level of method and of content.
Nevertheless, there seems to have been one aspect of Aristotle's system that Duhem found somewhat promising: its freedom from a priori selection of the primary qualities by which, in the manner of the mechanical philosophy of the seventeenth century, all secondary qualities had to be explained. For him, what qualities were primary and what secondary ought to be a purely pragmatic matter, decided by the progress of theory and experiment as successive theories succeeded in classifying wider and wider collections of data. Where, though, he differed from Aristotle is that his physics was to be a mathematical science; it was to classify qualities, not explain them, and do so by replacing their measured intensities by symbols subject to mathematical manipulation; it was to be mathematical science whose form no metaphysical system could decide a priori: that form too was to emerge from the progress of physics, as successive theoretical classifications of the mathematical intensities of qualities, and the implied classifications of the qualities these represented, hopefully converged on the natural classification that was the goal of physics.
Such was the 'Aristotelianism' that Duhem advertised in a variety of articles in the middle to late 1890s, particularly in his historical works culminating in Le Mixte et la Cominaison Chimique and L'Évolution de la Mécanique, before repeating it yet again in 'Physicque de Croyant' after which it disappears from view. It was a pretty minimal Aristotelianism, but after 1905 even that disappears from view. To my knowledge, Duhem never withdrew such views, but their disappearance from his later writings is indicative of his final decisive rejection of neo-Scholasticism and all it stood for, of those of his earlier attitudes that had made it reasonable for Blondel in 1893 to tease him as a peripatetic. Duhem's ultimate reasons for this shift are not completely clear—some possible answers will be explored later in this chapter—yet there can be no question but that it came at a critical time, when the so-called modernist crisis was at its height, and neo-Scholasticism lay at the hearth of that crisis.
I have already referred more than once to the Encyclical Pascendi Dominici Gregris of 1907: the prominent rôle neo-Scholasticism played in it can hardly escape the notice of any reader; implicit in the doctrinal part, it becomes explicit in the disciplinary part that follows. We are told that a distaste for the scholastic method is the surest sign of modernism in any writer (What else would be expected of an adherent of a modern philosophy but opposition to scholasticism?), and the text goes on to insist that scholastic philosophy is henceforth to be the basis for Catholic thought:

We will and ordain that scholastic philosophy be made the basis of the sacred sciences. [...] And let it be clearly understood above all things that the scholastic philosophy We prescribe is that which the Angelic Doctor has bequeathed to us, and We, therefore, declare that all the ordinances of Our Predecessor on this subject continue fully in force [...] Further let Professors remember that they cannot set St. Thomas aside, especially in metaphysical questions, without grave detriment.

The Angelic Doctor is a Scholastic appellation for Thomas Aquinas.
From all this Duhem had largely stood apart, and events will show him moving yet further away from it. Even in his historical work to date, unusual for its time in that Aristotle is taken seriously, there is no trace of the work on mediaeval science that was to be expected of a historically-minded Catholic scientist in that environment, and was in the end to do more than anything else to perpetuate Duhem's fame. But, as will be seen, when he does get involved in mediaeval science, what he finds is not perhaps what the Pope had in mind. While Pascendi was insisting on the centrality of scholastic philosophy Duhem was increasingly associated with a journal committed to opposing that philosophy. The best place to illustrate Duhem's developing distance from neo-Scholasticism is his association with the Annales de Philosophie Chrétienne.

—R.N.D. Martin's Pierre Duhem pgs. 38-49 with quotes from Pope Pius X's encyclical Pascendi Domenici Gregis

Duhem, like Heisenberg, thought there was a "sharp division between faith and science." Even though Duhem made noble discoveries in the history of science related to mediaeval science's contributions, due in large part to the Catholic Church, to modern science; he refused to see the importance of adopting a Scholastic-Thomistic philosophy not especially for theology but for science. Why is this philosophy needed? Primarily because it opposes Modernism and sees that faith and reason "are like two wings on which the human spirit rises to the contemplation of truth (bina quasi pennæ videntur quibus veritatis ad contemplationem hominis attollitur animus):"

III. Relation Between Faith and Science

Faith and Science
Q.—Can we now have some idea of the relations which the Modernists establish between faith and science, including, under this latter term, history?
A.—'16. Having reached this point [...] we have sufficient material in hand to enable us to see the relations which Modernists establish between faith and science, including history also under the name of science.'
Q.—What difference do they make between the object of the one and of the other?
A.—'And in the first place it is to be held that the object of the one is quite extraneous to and separate from the object of the other. For faith occupies itself solely with something which science declares to be unknowable for it. Hence each has a separate field assigned to it: science is entirely concerned with the reality of phenomena, into which faith does not enter at all; faith on the contrary concerns itself with the divine reality which is entirely unknown to science.
Q.—Then, according to them, no conflict is possible between faith and science?
A.—'Thus the conclusion is reached that there can never be any dissension between faith and science, for if each keeps on its own ground they can never meet and therefore never be in contradiction.
Q.—'And if it be objected that in the visible world there are some things which appertain to faith, such as the human life of Christ'?
A.—'The Modernists reply by denying this.'
Q.—How can they deny it?
A.—They say: 'For though such things come within the category of phenomena, still in as far as they are lived by faith and in the way already described have been by faith transfigured and disfigured, they have been removed from the world of sense and translated to become material for the divine.
Q.—'Hence should it be further asked whether Christ has wrought real miracles, and made real prophecies, whether He rose truly from the dead and ascended into heaven,' what do they answer?
A.—'The answer of agnostic science will be in the negative.
'The answer of faith in the affirmative'
Q.—But is not that a flagrant contradiction between science and faith?
'There will not be, on that account, any conflict between them. For it will be denied by the philosopher as philosopher, speaking to philosophers and considering Christ only in His historical reality; and it will be affirmed by the speaker, speaking to believers and considering the life of Christ as lived again by the faith and in the faith.'
Q.—Faith and science acting thus in entirely separate fields, will there be, according to the Modernists, no subordination of the one to the other.
A.—'17. [...] it would be a great mistake to suppose that, given these theories, one is authorised to believe that faith and science are independent of one another. On the side of science the independence is indeed complete, but it is quite different with regard to faith, which is subject to science.'
Q.—Faith subject to science! But on what ground?
A.—'Not on one but on three grounds.'
Q.—According to the Modernists, what is the first ground?
A.—'For in the first place it must be observed that in every religious fact, when you take away the divine reality and the experience of it which the believer possesses, everything else, and especially the religious formulas of it, belongs to the sphere of phenomena and therefore falls under the control of science. Let the believer leave the world if he will, but so long as he remains in it he must continue, whether he like it or not, to be subject to the laws, the observation, the judgments of science and of history.'
Q.—What is the second ground of the subordination of faith to science?
A.—'Further, when it is said that God is the object of faith alone, the statement refers only to the divine reality not to the idea of God. The latter also is subject to science which while it philosophises in what is called the logical order soars also to the absolute and the ideal. It is therefore the right of philosophy and of science to form conclusions concerning the idea of God, to direct it in its evolution and to purify it of any extraneous elements which may become confused with it.'
Q.—What is the third ground?
A.—'Finally, man does not suffer a dualism to exist in him, and the believer therefore feels within him an impelling need so to harmonise faith with science, that it may never oppose the general conception which science sets forth concerning the universe.'
Q.—Then, according to the Modernist doctrine, faith is in bondage to science?
A.—Yes. 'It is evident that science is to be entirely independent of faith, while on the other hand, and notwithstanding that they are supposed to be strangers to each other, faith is made subject to science.'
Q.—How did Pius XI and Gregory IX stigmatize such doctrine?
A.—'All this [...] is in formal opposition with the teachings of Our Predecessor, Pius IX, where he lays it down that: "In matters of religion it is the duty of philosophy not to command but to serve, but not to prescribe what is to be believed but to embrace what is to be believed with reasonable obedience, not to scrutinise the depths of the mysteries of God but to venerate them devoutly and humbly."
'The Modernists completely invert the parts, and to them may be applied the words of another Predecessor of Ours, Gregory IX., addressed to some theologians of his time: "Some among you, inflated like bladders with the spirit of vanity strive by profane novelties to cross the boundaries fixed by the Fathers, twisting the sense of the heavenly pages . . .to the philosophical teaching of the rationals, not for the profit of their hearer but to make a show of science ... these, seduced by strange and eccentric doctrines, make the head of the tail and force the queen to serve the servant."'

IV. Practical Consequences

The Methods of Modernists
18. [...]
Q.—Is this ["the mutual separation of science and faith"] done also in other scientific work?
A.—'So, too, acting on the principle that science in no way depends upon faith, when they treat of philosophy, history, criticism, feeling no horror at treading in the footsteps of Luther [Prop. 29, condemned by Leo X, Bull, Exsurge Domine, May 16, 1520: 'It is permissible to us to invalidate the authority of Councils, freely to gainsay their acts, to judge of their decrees, and confidently to assert whatever seems to us to be true, whether it has been approved or reprobated by any Council whatsoever.'], they are wont to display a certain contempt for Catholic doctrines, or the Holy Fathers, for the Ecumenical Councils, for the ecclesiastical magisterium; and should they be rebuked for this, they complain that they are being deprived of their liberty.'
[...]

I. Rules Relative to Studies

The Study of Scholastic Philosophy
[...]
Q.—Would it be a great disadvantage to set aside St. Thomas?
A.—'Further let Professors remember that they cannot set St. Thomas aside, especially in metaphysical questions, without grave detriment.'
[...]
Q.—According to what law ought the study of natural sciences to be regulated?
A.—'47. With regard to profane studies suffice it to recall here what Our Predecessor has admirably said: "Apply yourselves energetically to the study of natural sciences: the brilliant discoveries and the bold and useful applications of them made in our times which have won such applause by our contemporaries will be an object of perpetual praise for those that come after us" (Leo XIII. Alloc., March 7, 1880). But this do without interfering with sacred studies, as Our Predecessor in these most grave words prescribed: "If you carefully search for the cause of those errors you will find that it lies in the fact that in these days when the natural sciences absorb so much study, the more severe and lofty studies have been proportionately neglected—some of them have almost passed into oblivion, some of them are pursued in a half-hearted or superficial way, and, sad to say, now that they are fallen from their old estate, they have been disfigured by perverse doctrines and monstrous errors" (loco cit.). We ordain, therefore, that the study of natural science in the seminaries be carried on under this law.'
[...]

Conclusion
The Church and Scientific Progress

Triennial Returns
'57. This, Venerable Brethren, is what we have thought it our duty to write to you for the salvation of all who believe. The adversaries of the Church will doubtless abuse what we have said to refurbish the old calumny by which we are traduced as the enemy of science and of the progress of humanity. In order to oppose a new answer to such accusations, which the history of the Christian religion refutes by never failing arguments, it is Our intention to establish and develop by every means in our power a special Institute in which, through the co-operation of those Catholics who are most eminent for their learning, the progress of science and other realms of knowledge may be promoted under the guidance and teaching of Catholic truth. God grant that we may happily realise our design with the ready assistance of all those who bear a sincere love for the Church of Christ. But of this we will speak on another occasion.
'58. Meanwhile, Venerable Brethren, fully confident in your zeal and work, we beseech for you with our whole heart and soul the abundance of heavenly light, so that in the midst of this great perturbation of men's minds from the insidious invasions of error from every side, you may see clearly what you ought to do and may perform the task with all your strength and courage. May Jesus Christ, the author and finisher of our faith, be with you by His power; and may the Immaculate Virgin, the destroyer of all heresies, be with you by her prayers and aid. And We, as a pledge of Our affection and of divine assistance in adversity, grant most affectionately and with all Our heart to you, your clergy and people the Apostolic Benediction.
'Given at St. Peter's, Rome, on the 8th day of September, 1907, the fifth year of our Pontificate.'

—Fr. John Fitzpatrick's Catechism of Modernism with quotes from Pope Pius X's encyclical Pascendi Domenici Gregis

Even though Pope St. Pius X says that one "cannot set St. Thomas aside [...] without grave detriment," he was primarily referring to the teaching and study of theology, and in section 47. appears to think the natural sciences should be regulated by a different set of rules and "without interfering with sacred studies." Yet in both cases he is stressing the importance of St. Thomas's "perennial philosophy" in order to avoid "perverse doctrines and monstrous errors" not only in sacred sciences but also in the "profane" or secular natural sciences as well. A notable example of a "perverse doctrine" or teaching in physics is the "many worlds" interpretation of quantum mechanics. In the solid "perennial philosophy," only one world can exist. (Summa Theologica Iª q. 47 a. 3).

The mathematician and philosopher Wolfgang Smith (author of "From Schrödinger's Cat to Thomistic Ontology" in The Thomist) calls Modernism's influence on science the "plague of scientistic belief:"

Yet, despite the fact of quantum indeterminism, not a few eminent scientists continue to champion the mechanistic tenet. Albert Einstein himself, as one knows, so far from admitting that the discoveries of quantum physics have overthrown the classical postulate, argued precisely in the opposite direction: it is the principle of determinism, he said in effect, that invalidates quantum mechanics as a fundamental theory. This illustrates quite clearly the philosophical and indeed a priori character of the tenet in question, and the fact that propositions of this kind can neither be verified nor falsified by empirical findings. This fact, however, remains generally unrecognized, with the result that the postulate of universal mechanism has retained to this day its status as a major article of scientistic belief.
My second example pertains to a more fundamental stratum of philosophical thought, and is consequently still more far-reaching in its implications: “physical reductionism,” let us call it (for reasons which will presently become clear). The thesis hinges upon an epistemological assumption, an idealist postulate, one could say, which affirms that the act of sense perception terminates, not in an external object as we commonly believe, but in a subjective representation of some kind. According to this view, the red apple which we perceive exists somehow in our mind or consciousness; it is a subjective image, a fantasy which mankind has all along mistaken for an external object. Thus thought René Descartes, to whom we owe the philosophical foundations of modern science. Descartes sought to correct what he took to be the mistaken notions of mankind concerning perceptible entities by distinguishing between the external object, which he termed res extensa, and its subjective representation existing in the mind or so-called res cogitans. What was previously conceived as a single object (and what in daily life is invariably regarded as such) has therefore become split in two; as Whitehead has put it: “Thus there would be two natures, one is the conjecture and the other is the dream.” It is to be noted that this Cartesian differentiation between the “conjecture” and the “dream” goes not only against the common intuitions of mankind, but is equally at odds with the great philosophical traditions, including especially the Thomistic, where the opposition becomes as it were diametrical. Now, it is this questionable Cartesian doctrine—which Whitehead refers to as “bifurcation”—that has served from the start as the fundamental plank of physics, or better said, of the scientistic world-view in terms of which we habitually interpret the results of physics. And once again we find that the two disparate factors—the operational facts of physics and their customary interpretation—have become in effect identified, which is to say that the tenet of bifurcation does indeed function as a scientistic belief.
I would like to emphasize that in addition to the fact that bifurcation contradicts the most basic human intuitions as well as the most venerable philosophical traditions, there is also not a shred of empirical evidence in support of this heterodox position. Nor can there be, as follows from the fact that physics can be perfectly well interpreted on a non-bifurcationist basis, as I have shown in a recent monograph. It turns out, moreover, that the moment one does interpret physics in non-bifurcationist terms, the so-called quantum paradoxes—which have prompted physicists to invent the most bizarre ontologies—vanish of their own accord. It seems that quantum physics has thus implicitly sided with the pre-Cartesian world-view.

—Wolfgang Smith's "The Plague of Scientistic Belief"

This mechanism has far-reaching philosophical consequences which in turn influence how subsequent science is performed and interpreted. E.g., in Galileo's description of tickling, he adopts a subjectivist, agnostic philosophy because he denies that the nature of "feather," something beyond the senses, can be known; for him, sense knowledge begins and ends in the senses.

I move my hand first over a marble statue and then over a living man. To the effect flowing from my hand, this is the same with regard to both objects and my hand [Here he assumes spatial motion is all that matters.]; it consists of the primary phenomena of motion and touch, for which we have no further names. But the live body which receives these operations feels different sensations according to the various places touched. When touched upon the soles of the feet, for example, or under the knee or armpit, it feels in addition to the common sensation of touch a sensation on which we have imposed a special name, "tickling." This sensation belongs to us and not to the hand. Anyone would make a serious error if he said that the hand, in addition to the properties of moving and touching, possessed another faculty of "tickling," as if tickling were a phenomenon that resided in the hand that tickled. A piece of paper or a feather drawn lightly over any part of our bodies performs intrinsically the same operations of moving and touching, but by touching the eye, the nose, or the upper lip it excites in us an almost intolerable titillation, even though elsewhere it is scarcely felt. This titillation belongs entirely to us and not to the feather [therefore subjectivism]; if the live and sensitive body were removed it would remain no more than a mere word. I believe that no more solid an existence belongs to many qualities which we have come to attribute to physical bodies-tastes, odors, colors, and many more.

—Galileo's Il Saggiatore pg. 275

As interesting as Gailileo's description of tickling may be, he is wrong. Here is why:

Those who hold for the subjectivity of sensible qualities maintain that such qualities have no existence independently of the sensing subject, and on this ground effectively deny the very existence of objective intentions for such qualities. They find convincing Galileo's example of the movement of a feather across the skin to explain the tickle. So they introduce a distinction between primary qualities such as movement and secondary qualities such as the sensed tickle, and hold that the primary qualities have objective existence whereas secondary qualities do not. As a result they populate the universe with particles in motion and attempt to explain all sensations by the various kinds of movement these particles undergo, meanwhile denuding the objective world of sensible qualities in their traditional understanding.
The source of the difficulty here is an improper grasp of the role of the mental representation in the knowledge act. To think of the concept as what is known, rather than seeing that the nature is what is known, though by means of the concept, is to cut oneself off from intellectual knowledge of the real, for one is always left wondering about any extra-mental reality to which the concept might correspond. Similarly, to think of the sensation or the percept as itself what is known, rather than seeing the sensible quality as what is known, though by means of the sensation or percept, is to be imprisoned within one's sense organs and brain. The result is a radical solipsism that prohibits individuals from ever making statements about the objects of experience, leaving them to dwell in a world of their own imaginings.
The tickle may be something sensed on the surface of the skin, but that admission surely does not permit the inference that there is no movement there, or extending the argument further to hold that there is no heat in boiling water, no color in a ruby or a rose, no sound in the cry of a bird, or no odor or taste in an onion. All of these are accidents or accidental modifications of the subjects in which they are sensed. Just as those subjects have natures (inorganic, plan or animal in kind), so accidents may be said to have natures in an analogous sense. And even if we cannot know precisely the nature of heat, of color, and so on, we can at least model those natures in terms of the modalities they introduce in the components of the substantial natures in which they exist, namely the electrons, atoms, and molecules [...]

—Fr. William A. Wallace, O.P.'s The Modeling of Nature (pgs. 148-149)

With the adoption of a Thomistic philosophy, we can avoid all these sorts of philosophical and scientific methodological errors; we can interpret quantum mechanics correctly, for example; and, in short, we can prevent scientistic belief from plaguing science.