On St. Albert the Great's Feast Day: Magisterium on the True Scientific Method

Pope Leo XIII says in his 4 August 1879 encyclical on the restoration of Christian philosophy, Æterni Patris:

30. And here it is well to note that our philosophy can only by the grossest injustice be accused of being opposed to the advance and development of natural science. For, when the Scholastics, following the opinion of the holy Fathers, always held in anthropology that the human intelligence is only led to the knowledge of things without body and matter by things sensible, they well understood that nothing was of greater use to the philosopher than diligently to search into the mysteries of nature and to be earnest and constant in the study of physical things. And this they confirmed by their own example; for St. Thomas, Blessed [now Saint] Albertus Magnus, and other leaders of the Scholastics were never so wholly rapt in the study of philosophy as not to give large attention to the knowledge of natural things; and, indeed, the number of their sayings and writings on these subjects, which recent professors approve of and admit to harmonize with truth, is by no means small. Moreover, in this very age many illustrious professors of the physical sciences openly testify that between certain and accepted conclusions of modern physics and the philosophic principles of the schools there is no conflict worthy of the name.

Happy feast day today of St. Albert the Great!

Science, Truth, & Morality

Just as Einstein noted that a physicist must not restrict himself solely to physics but must also be a philosopher so that he can "make clear in his own mind just how far the concepts which he uses are justified, and are necessities," Pope Benedict XVI, in his 2009 encyclical letter Caritas in Veritate ("Charity in Truth"), relates the importance of combating a segmentation of knowledge to that of economic prosperity (my emphasis and [comments]):

30. In this context, the theme of integral human development takes on an even broader range of meanings: the correlation between its multiple elements requires a commitment to foster the interaction of the different levels of human knowledge in order to promote the authentic development of peoples. Often it is thought that development, or the socio-economic measures that go with it, merely require to be implemented through joint action. This joint action, however, needs to be given direction, because “all social action involves a doctrine”. In view of the complexity of the issues, it is obvious that the various disciplines have to work together through an orderly interdisciplinary exchange. Charity does not exclude knowledge, but rather requires, promotes, and animates it from within. Knowledge is never purely the work of the intellect. It can certainly be reduced to calculation and experiment, but if it aspires to be wisdom capable of directing man in the light of his first beginnings and his final ends, it must be “seasoned” with the “salt” of charity. Deeds without knowledge are blind, and knowledge without love is sterile. [Summa Theologiæ, Iª q. 12 a. 13 ad 3: "[Faith is] a kind of knowledge, inasmuch as the intellect is determined by faith to some knowable object." Cf. this.] Indeed, “the individual who is animated by true charity labours skilfully to discover the causes of misery, to find the means to combat it, to overcome it resolutely”. Faced with the phenomena that lie before us, charity in truth requires first of all that we know and understand, acknowledging and respecting the specific competence of every level of knowledge. Charity is not an added extra, like an appendix to work already concluded in each of the various disciplines: it engages them in dialogue from the very beginning. The demands of love do not contradict those of reason. Human knowledge is insufficient and the conclusions of science cannot indicate by themselves the path towards integral human development. There is always a need to push further ahead [This is what Einstein means, too, by saying: "At a time like the present, when experience forces us to seek a newer and more solid foundation..."]: this is what is required by charity in truth. Going beyond, however, never means prescinding from the conclusions of reason, nor contradicting its results. Intelligence and love are not in separate compartments: love is rich in intelligence and intelligence is full of love.

31. This means that moral evaluation and scientific research must go hand in hand [Morality involves determining what the greatest good is in a given situation. It involves much more than resolving never to kill anybody, to "be nice," etc. It guides even questions in science such as "How should I approach this problem?", "What methodology should I use?", "Where is it taking me?", "It is worth it?", etc.; consequently, morality is vitally important for those who seek truth (cf. Veritatis Splendor).], and that charity must animate them in a harmonious interdisciplinary whole, marked by unity and distinction. The Church's social doctrine, which has “an important interdisciplinary dimension”, can exercise, in this perspective, a function of extraordinary effectiveness. It allows faith, theology, metaphysics and science to come together in a collaborative effort in the service of humanity. It is here above all that the Church's social doctrine displays its dimension of wisdom. Paul VI had seen clearly that among the causes of underdevelopment there is a lack of wisdom and reflection, a lack of thinking capable of formulating a guiding synthesis, for which “a clear vision of all economic, social, cultural and spiritual aspects” is required. The excessive segmentation of knowledge [Cf. John Paul II, Encyclical LetterFides et Ratio (14 September 1998), 85: AAS 91 (1999), 72-73.], the rejection of metaphysics by the human sciences [Cf. ibid., 83: loc. cit., 70-71.], the difficulties encountered by dialogue between science and theology are damaging not only to the development of knowledge, but also to the development of peoples, because these things make it harder to see the integral good of man in its various dimensions. The “broadening [of] our concept of reason and its application” [Benedict XVI, Address at the University of Regensburg, 12 September 2006.] is indispensable if we are to succeed in adequately weighing all the elements involved in the question of development and in the solution of socio-economic problems.

An excellent book that tackles this problem is The Way toward Wisdom (vide this excerpt and this article) by Benedict Ashley, O.P., a proponent of River Forest Thomism.

"Faith, Reason, and Science" by Clifford Simske, MD

From the Tucson Catholic Physician Guild's September 2011 meeting:

Click here to download an OCRed version Dr. Simske's notes.

Physicsts Must Also Be Philosophers.

Einstein, in his Physics & Reality, says that physicists must also be philosophers:

It has often been said, and certainly not without justification, that the man of science is a poor philosopher. Why then should it not be the right thing for the physicist to let the philosopher do the philosophizing? Such might indeed be the right thing at a time when the physicist believes he has at his disposal a rigid system of fundamental concepts and fundamental laws which are so well established that waves of doubt can not reach them; but it can not be right at a time when the very foundations of physics itself have become problematic as they are now. At a time like the present, when experience forces us to seek a newer and more solid foundation, the physicist cannot simply surrender to the philosopher the critical contemplation of the theoretical foundations; for, he himself knows best, and feels more surely where the shoe pinches. In looking for a new foundation, he must try to make clear in his own mind just how far the concepts which he uses are justified, and are necessities.

And by being its philosophers, he does not mean being its undertakers; for, as Étienne Gilson observed, philosophy "always buries its undertakers." Hence the necessity for a Thomistic revival in modern mathematical physics, Thomism being the philosophical foundation of modern science.

The Truth of Science for Justice and Peace

Monsignor Marcelo Sánchez Sorondo, who graduated from the Angelicum magna cum laude and is chancellor of both the Pontifical Academy of the Sciences and the Pontifical Academy of the Social Sciences, gave the keynote speech for Arizona State University (ASU)'s Consortium of Science, Policy, & Outcomes entitled "The Truth of Science for Justice and Peace" on May 18, 2010. It included many references to St. Thomas Aquinas. Here is an excerpt of the interview afterwards:

The transcript and full presentation slides:

And a commentary by the ASU philosopher Farzad Mahootian:

Other enlightening reactions to the Monsignor's speech include those of Heather Douglas, Associate Professor, Philosophy, University of Tennessee and Carl Mitcham, Professor, Liberal Arts and International Studies, Colorado School of Mines.

Heather Douglas's article quotes this by St. Bernard of Clairvoux, which the Monsignor quoted in his speech:

“There are people who only wish to know for the sake of knowing: this is base curiosity. Others wish to know in order that they themselves may be known: this is shameful vanity, and such people cannot escape the mockery of the satirical poet who said about their likes: ‘For you, knowing is nothing unless someone else knows that you know.’ Then there are those who acquire knowledge in order to re-sell it, and for example to make money or gain honours from it: their motive is distasteful. But some wish to know in order to edify: this is charity. Others in order to be edified: this is wisdom. Only those who belong to these last two categories do not misuse knowledge, since they only seek to understand in order to do good.” (Quoted on pp. 5-6, from St. Bernardus, Sermo XXXVI in Cantica, PL, CLXXXIII, 968.)

The science before science

Galileo Truly Recanted.

Was Galileo really a martyr of modern science, the theories and explanations of which are in a constant state of flux, or did he ultimately seek an absolute, unchanging, objective Truth and recant of holding a changeable scientific theory to be objectively true? Galileo wrote to Francesco Rinuccini, Arcetri, 29 March 1641, the year before his death:

The falsity of the Copernican system needs not be called into doubt, and especially by us Catholics, having the irrefragable authority of Sacred Scripture, interpreted by the supreme masters in Theology, whose concordant consensus renders us certain of the stability of the Earth placed in the center, and of the mobility of the Sun around it. The conjectures then for which Copernicus and his other followers have professed the contrary, are all lifted with that most solid argument of the Omnipotence of God, Who can do in diverse—rather, in infinite ways—that to our opinion and observation seem done in one particular way; we should not want to shorten the hand of God and tenaciously sustain that in which we can be deceived.

—Le opere di Galileo Galilei, vol. 7 edited by Vincenzio Viviani [my translation]

Galileo, were he alive in the 19th and 20th centuries, respectively, would agree with these statements:

[...] if writers on physics travel outside the boundaries of their own branch, and carry their erroneous teaching into the domain of philosophy, let them be handed over to philosophers for refutation.

—Pope Leo XIII's Providentissimus Deus

Human science gains greatly from revelation, for the latter opens out new horizons and makes known sooner other truths of the natural order, and because it opens the true road to investigation and keeps it safe from errors of application and of method. Thus does the lighthouse show many things they otherwise would not see, while it points out the rocks on which the vessel would suffer shipwreck.

—Pope St. Pius X's Iucunda Sane

Believe, that you may understand.

Atheist scientists frequently contend that doubt, which is opposed to faith, and skepticism are the most necessary virtues for a scientist. They argue that because we are, as Carl Sagan put it, stardust living on a "pale blue dot," we have no right hubristically to value human life over anything else; we must remain "humble." Consequently, they oppose any form of dogmatism that impedes free inquiry and unrestricted academic freedom.

Even King David, after beholding "the moon and the stars," humbly asks their Creator: "What is man that thou art mindful of him?" (Psalm 8:4-5). And even St. Thomas the Apostle ("Doubting Thomas") was the first doubting scientist:

Now Thomas, one of the twelve, who is called Didymus, was not with them when Jesus came. The other disciples therefore said to him: We have seen the Lord. But he said to them: Except I shall see in his hands the print of the nails, and put my finger into the place of the nails, and put my hand into his side, I will not believe. And after eight days again his disciples were within, and Thomas with them. Jesus cometh, the doors being shut, and stood in the midst, and said: Peace be to you. Then he saith to Thomas: Put in thy finger hither, and see my hands; and bring hither thy hand, and put it into my side; and be not faithless, but believing. Thomas answered, and said to him: My Lord, and my God. Jesus saith to him: Because thou hast seen me, Thomas, thou hast believed: blessed are they that have not seen, and have believed.

—John 20:24-29

—The Incredulity of St. Thomas the Apostle by Michelangelo Caravaggio (c. 1571-1610)

How can we make sense of this? Does it apply to understanding everything? What does St. Anselm mean when he says "faith seeking understanding" (fides quærens intellectum) and "Nor do I seek to understand that I may believe, but I believe that I may understand [credo ut intelligam]. For this too I believe, that unless I first believe, I shall not understand [«nisi credidero, non intelligam», St. Augustine Sermo 43 7,9; cf. Isaias 7:9]." (Proslogion I)? St. Augustine—the 5th century saint whose theory of time is frequently quoted in the quantum cosmology literature, e.g., in Rev. Mod. Phys. 61, 1 (1989) pg. 15—says:

7. [...]

What were we arguing about? You were saying “Let me understand in order to believe”; I was saying “In order to understand, believe.” An argument has arisen, let us put it before a judge, let a prophet judge, or rather let God judge through a prophet. Let's both of us keep silent. What we have each said has been heard: “Let me understand,” you say, “in order to believe.” “Believe,” say I, “in order to understand.” Let the prophet make his reply: “Unless you believe, you shall not understand” (Is 7:9).

[...]

9. Just now when the gospel was being read, you heard If you can believe—the Lord Jesus said to the boy's father, If you can believe, all things are possible to one who believes (Mk 9:23). And the man took a look at himself, and standing in front of himself, not in a spirit of brash self-satisfaction but first examining his conscience, he saw that he did have some faith in him, and he also saw that it was tottering. He saw both things. He confessed he had one, and he begged for help for the other. I believe, Lord, he says. What was to follow, if not “Help my faith”? That's not what he said. “I believe, Lord. I can see this something in me, which I'm not lying about. I believe; I'm telling the truth. But I also see this other heaven knows what, and I don't like it. I want to stand, I'm still staggering. I'm standing and speaking, I haven't fallen, because I believe. But yet I'm still staggering: Help my unbelief” (Mk 9:24).

And so, beloved, that other man too whom I set up against myself, calling in the prophet as referee because of the argument that arose between us, he too isn't saying just nothing when he says “Let me understand, in order to believe.” Of course, what I am now saying, I am saying to help those people believe who do not yet believe. And yet, unless they understand what I am saying, they cannot believe. So what this person says is partly true—“Let me understand, in order to believe”; and I on my side, when I say, just as the prophet says, “On the contrary, believe, in order to understand,” am speaking the truth. Let's come to an agreement, then. So: understand, in order to believe; believe, in order to understand. I'll put it in a nutshell, how we can accept both without argument: Understand, in order to believe, my word; believe, in order to understand, the word of God.

—St. Augustine's Sermo 43 7,9

So, many modern atheist scientists are missing faith, one of the "two wings on which the human spirit rises to the contemplation of truth," which are faith and reason (Fides et Ratio 1.). As a result, doubt hinders the full contemplation of the absolute truths.

Obviously, though, atheists would object to most of what has been said, e.g., the invoking of God and absolutes. They might say:

Why is any of this necessary for science, which just studies contingent—viz., non-necessary—things? It is untrue that "faith purifies reason" (fides purificat rationem) and "liberates [it] from presumption" ([fides] rationem a nimia confidentia exsolvit), no (Fides et Ratio 76.)? Faith, especially that of organized religions, has destroyed science by enslaving it to outdated, primitive presumptions, e.g., that the universe and everything in it was created in a week. [To which I would immediately respond, due to their misunderstanding: "St. Augustine, e.g., wrote that the Genesis 'day' is not necessarily 24 hours. In fact, before the earth and sun were created, how could one even define 'day' anyways?"] Modern science has enlightened us now. We no longer need blind religion or anything else besides our intellects and reason for our guide.

The problem with this sort of Cartesian "Cogito, ergo sum" ("I think; therefore, I am.") is that it denies an objective reality and makes us our own authorities even on matters of which we are often unqualified to judge; this is extreme Protestantism. The atheist scientists might maintain that truth is relative but they have no way of scientifically justifying this. In a sense, what they have faith in is what is most detrimental to science: agnosticism, in the sense that the human intellect can never know anything with certainty, even the basic premises of logic such as the law of non-contradiction or the syllogism, and that which follows from it: extreme doubt, skepticism, and nihilism. Even the pagan Aristotle realized—almost á la Kurt Gödel and his Incompleteness Theorem—that, although there is scientific knowledge, not all truths are demonstrable as through a syllogism or science experiment; Aristotle was therefore one of the first anti-positivists (on positivism, cf. Card. Schönborn's "The Designs of Science"). We quote first his Posterior Analytics—a book that even Galileo faithfuflly followed despite his disagreements with Aristotle's physics—on "The erroneous views of scientific knowledge" and "The futility of circular demonstration," both of which I believe many atheist scientists are culpable, then we follow it by St. Thomas Aquinas's commentary, which more illuminates Aristotle's work in the present context of "crede, ut intelligas:"

3

Some hold that, owing to the necessity of knowing the primary premisses, there is no scientific knowledge. Others think there is, but that all truths are demonstrable. Neither doctrine is either true or a necessary deduction from the premisses. The first school, assuming that there is no way of knowing other than by demonstration, maintain that an infinite regress is involved, on the ground that if behind the prior stands no primary, we could not know the posterior through the prior (wherein they are right, for one cannot traverse an infinite series): if on the other hand—they say—the series terminates and there are primary premisses, yet these are unknowable because incapable of demonstration, which according to them is the only form of knowledge. And since thus one cannot know the primary premisses, knowledge of the conclusions which follow from them is not pure scientific knowledge nor properly knowing at all, but rests on the mere supposition that the premisses are true. The other party agree with them as regards knowing, holding that it is only possible by demonstration, but they see no difficulty in holding that all truths are demonstrated, on the ground that demonstration may be circular and reciprocal.

Our own doctrine is that not all knowledge is demonstrative: on the contrary, knowledge of the immediate premisses is independent of demonstration. (The necessity of this is obvious; for since we must know the prior premisses from which the demonstration is drawn, and since the regress must end in immediate truths, those truths must be indemonstrable.) Such, then, is our doctrine, and in addition we maintain that besides scientific knowledge there is its originative source which enables us to recognize the definitions.

Now demonstration must be based on premisses prior to and better known than the conclusion; and the same things cannot simultaneously be both prior and posterior to one another: so circular demonstration is clearly not possible in the unqualified sense of ‘demonstration’, but only possible if ‘demonstration’ be extended to include that other method of argument which rests on a distinction between truths prior to us and truths without qualification prior, i.e. the method by which induction produces knowledge. But if we accept this extension of its meaning, our definition of unqualified knowledge will prove faulty; for there seem to be two kinds of it. Perhaps, however, the second form of demonstration, that which proceeds from truths better known to us, is not demonstration in the unqualified sense of the term.

The advocates of circular demonstration are not only faced with the difficulty we have just stated: in addition their theory reduces to the mere statement that if a thing exists, then it does exist—an easy way of proving anything. That this is so can be clearly shown by taking three terms, for to constitute the circle it makes no difference whether many terms or few or even only two are taken. Thus by direct proof, if A is, B must be; if B is, C must be; therefore if A is, C must be. Since then—by the circular proof—if A is, B must be, and if B is, A must be, A may be substituted for C above. Then ‘if B is, A must be’=’if B is, C must be’, which above gave the conclusion ‘if A is, C must be’: but C and A have been identified. Consequently the upholders of circular demonstration are in the position of saying that if A is, A must be—a simple way of proving anything. Moreover, even such circular demonstration is impossible except in the case of attributes that imply one another, viz. ‘peculiar’ properties.

Now, it has been shown that the positing of one thing—be it one term or one premiss—never involves a necessary consequent: two premisses constitute the first and smallest foundation for drawing a conclusion at all and therefore a fortiori for the demonstrative syllogism of science. If, then, A is implied in B and C, and B and C are reciprocally implied in one another and in A, it is possible, as has been shown in my writings on the syllogism, to prove all the assumptions on which the original conclusion rested, by circular demonstration in the first figure. But it has also been shown that in the other figures either no conclusion is possible, or at least none which proves both the original premisses. Propositions the terms of which are not convertible cannot be circularly demonstrated at all, and since convertible terms occur rarely in actual demonstrations, it is clearly frivolous and impossible to say that demonstration is reciprocal and that therefore everything can be demonstrated.

4

Since the object of pure scientific knowledge cannot be other than it is, the truth obtained by demonstrative knowledge will be necessary. And since demonstrative knowledge is only present when we have a demonstration, it follows that demonstration is an inference from necessary premisses.

—Aristotle's Posterior Analytics bk. 1 ch. 3-4 (72^b5-24)

Lecture 7
(72b5-24)
DISCUSSION OF TWO ERRORS—EXCLUSION OF THE FIRST ONE

b5. Some hold that, owing— b8. The first school— b15. The other party agree— b18. Our own doctrine is that

After determining about the knowledge of the principles of demonstration, the Philosopher now excludes the errors which have arisen from these determinations. Concerning this he does three things. First, he states the errors. Secondly, the reasons they erred (72b8). Thirdly, he removes the roots of these reasons (72b 18).

He says therefore first (72b5), that two contrary errors have arisen from one of the truths established above. For it has been established above that the principles of demonstration must be known and must be even better known. But the first of these is sufficient for our purpose. For some, basing themselves on this first statement, have come to believe that there is no science of anything, whereas others believe that there is science, even to the extent of believing that there is science of everything through demonstration. But neither of these positions is true and neither follows necessarily from their reasons.

Then (72b8) he presents the reasons why they have fallen into these errors. And first of all he presents the reason given by those who say that there is no science, and it is this: The principles of demonstration either proceed to infinity or there is a halt somewhere. But if there is a process to infinity, nothing in that process can be taken as being first, because one cannot exhaust an infinite series and reach what is first. Consequently, it is not possible to know what is first. (They are correct in thus arguing, for the later things cannot be known unless the prior ones are known).

On the other hand, if there is a halt in the principles, then even so, the first things are still not known, if the only way to know scientifically is through demonstration. For first things do not have prior principles through which they are demonstrated. But if the first things are not known, it follows again that the later things are not known in the strict and proper sense, but only on condition that there are principles. For it is not possible for something to be known in virtue of something not known, except on condition that that unknown be a principle. So in either case, whether the principles stop or go on to infinity, it follows that there is no science of anything.

Secondly (72b15), he presents the reasoning of those who say that there is science of everything through demonstration, because to their basic premise—the only way to know scientifically is by demonstration—they added another, namely, that one may demonstrate circularly. From these premises it followed that even if a limit is reached in the series of the principles of demonstration, the first principles are still known through demonstration, because, they said, those principles were demonstrated by previous ones. For a circular demonstration is one which is reciprocal, i.e., something which was first a principle is later a conclusion, and vice versa.

Then (72b18) he cuts away the false bases of these arguments. First, their supposition that the only way to know scientifically is by demonstration. Secondly, their statement that it is legitimate to demonstrate circularly (72b25).

He says therefore first (72b18), that not all scientific knowledge is demonstrative, i.e., obtained through demonstration, but the scientific knowledge of immediate principles is indemonstrable, i.e., not obtained by demonstration. However, it should be noted that Aristotle is here taking science in a wide sense to include any knowledge that is certain, and not in the sense in which science is set off against understanding, according to the dictum that science deals with conclusions and understanding [intuition] with principles.

But that it is necessary for some things to be held as certain without demonstration he proves in the following way: It is necessary that the prior things from which a demonstration proceeds be known in a scientific way. Furthermore, these must be ultimately reduced to something immediate; otherwise one would be forced to admit that there is an actual infinitude of middles between two extremes—in this case between the subject and predicate. Again, one would have to admit that no two extremes could be found between which there would not be an infinitude of middles. But as it is, the middles are such that it is possible to find two things which are immediate. But immediate principles, being prior, must be indemonstrable. Thus it is clear that it is necessary for some things to be scientifically known without demonstration.

Therefore, if someone were to ask how the science of immediate principles is possessed, the answer would be that not only are they known in a scientific manner, but knowledge of them is the source of a science. For one passes from the knowledge of principles to a demonstration of conclusion on which science, properly speaking, bears. But those immediate principles are not made known through an additional middle but through an understanding of their own terms. For as soon as it is known what a whole is and what a part is, it is known that every whole is greater than its part, because in such a proposition, as has been stated above, the predicate is included in the very notion of the subject. And therefore it is reasonable that the knowledge of these principles is the cause of the knowledge of conclusions, because always, that which exists in virtue of itself is the cause of that which exists in virtue of something else.

Lecture 8
(72b-73a20)
THE SECOND ERROR IS EXCLUDED BY SHOWING THAT CIRCULAR DEMONSTRATION IS NOT ACCEPTABLE

b25. Now demonstration must— b33. The advocates of circular— b38. Thus by direct proof— a1. Since then— a6. Moreover, even such

After excluding one false basis by showing that not all science depends on demonstration, the Philosopher now excludes another by showing that it is not possible to demonstrate circularly.

To understand this it should be noted that a demonstration is circular when the conclusion and one of the premises (in converted form) of a syllogism are used to prove the other premise. For example, we might form the following syllogism:

Every rational mortal animal is risible;

Every man is a rational mortal animal:

Therefore, every man is risible.

Now if the conclusion were to be used as one principle and the minor in converted form as the other, we would get:

Every man is risible;

Every rational mortal animal is a man:

Therefore, every rational mortal animal is risible—which was the major of the first syllogism.

Accordingly, he presents three arguments to show that it is not possible to demonstrate circularly. The first of these (72b25) is this: In a circular syllogism the same thing is at once a conclusion and a principle. But a principle of a demonstration is prior to and better known than the conclusion, as has been shown above. Therefore, it follows that a same thing is both prior to and subsequent to one same thing, and also more known and less known. But this is impossible. Therefore, it is impossible to demonstrate circularly.

But someone might say that a same thing can be both prior and subsequent, although not in the same way. For example, this might be prior in reference to us, but that prior absolutely. Thus singulars are prior in reference to us and subsequent absolutely: and conversely for universals. Again, induction makes something known in one way and demonstration in another way. For demonstration proceeds from things that are prior absolutely, but induction from things that are prior in reference to us.

Now if a circular demonstration were so constructed that something is first concluded from things that are absolutely prior, and then from things that are prior in reference to us, it would follow that our doctrine on scientific knowing was not well established. For we stated that to know scientifically is to know the cause of a thing. From this it followed that a demonstration which causes scientific knowledge must proceed from the absolutely prior. But if demonstration were at one time to proceed from the absolutely prior and at another time from things which are prior in reference to us, we would be forced to admit that scientific knowing is not confined to knowing the cause of a thing, but that there is another, namely, that form of knowing which proceeds from what is later. Therefore, one must either admit both or admit that the second form, namely, the demonstration which proceeds from what is better known to us is not a demonstration in the absolute sense.

The aforesaid also reveals why a dialectical syllogism can be circular. For it proceeds from things which are probable. But things are said to be probable if they are better known to the wise or to a great number of persons. Consequently, a dialectical syllogism proceeds from things that are better known to us. However, it happens that a same thing is better known to some and less known to others. Consequently, there is nothing to hinder a dialectical syllogism from being circular. But a demonstration is formed from things that are absolutely prior. Therefore, as we have already stated, there cannot be circular demonstration.

Then he sets forth the second argument (72b33) and it is this: If there were circular demonstration, it would follow that a same thing is demonstrated by the same thing, as if I were to say: If it is this, it is this. In this way it is easy for anyone to demonstrate everything, for anyone, wise or ignorant, will be able to do this. Accordingly, science is not acquired through demonstration. But this is against the definition of demonstration. Therefore, there cannot be circular demonstration.

He proves the truth of the first consequence in the following way: It is obvious, first of all, that with a circular demonstration the same thing is proved by a same thing, as has been stated above, i.e., if only three terms are employed; although it makes no difference whether the reflexion be made with fewer terms or more. (By reflexion he means the process whereby one goes from principle to conclusion in a demonstration, and then from conclusion to principle). In such a reflexion it makes no difference, so far as the force of the argument is concerned, whether it involves several or fewer terms or even two. For an argument has the same force if one proceeds thus: “If it is A, it is B, and if it is B, it is C, and if it is C, it is D,” and then by reflecting continues, “If it is D, it is C, and if it is C, it is B, and if it is B, it is A”; or if he proceeds by reflecting at the very start, saying: “If it is A, it is B, and if it is B, it is A.” (Although he spoke above of three terms, he restricted himself to two terms in this example, because in the deduction he is about to make he will use a third term, which is the same as the first).

Then (72b38) he gives the form of the argument in three terms, namely: “If it is A, it is B, and if it is B, it is C; therefore, if it is A, it is of necessity C.”

Then (73a1) he shows by the aforesaid form of arguing that in a circular demonstration a same thing is proved by a same thing, using only two terms. For it consists in saying, “If it is A, it is B,” and then reflecting, “If it is B, it is A”—which is a circular demonstration. Now according to the above given form it follows from these two, that “if it is A, it is A.”

That it does follow is obvious: for just as in the first deduction which involved three terms’ C followed from B, so in the reflex deduction of two terms, A followed from B. Let us suppose, then, that the A of the second deduction, i.e., the reflex, signifies the same thing that C signified in the first, i.e., in the direct deduction which was composed of three terms. Therefore, to state in the second deduction that “if it is B it is A” is to state the same thing as was stated in the first deduction, namely, that “if it is B, it is C.” But when it was stated in the first deduction that “if it is B, it is C,” it followed that “if it is A, it is C.” Therefore, in the circular deduction it follows that “if it is A, it is A,” since C is assumed to be the same as A. In this way, it will be easy to demonstrate all things, as has been said.

Then he presents the third argument (73a6) which is this: Those who suppose that everything can be known through demonstration on the ground that demonstration is circular, must grant that anything can be demonstrated by a circular demonstration and, as a consequence, grant that in a circular demonstration each of the premises can be concluded from the conclusion. However, the only cases in which this can be done are those in which mutual conversion is possible, i.e., in things that are convertible, as properties. But not all things are so related. Therefore, it is ridiculous to say that everything can be demonstrated on the ground that there are such things as circular demonstrations.

Now the reason is obvious why in a circular demonstration all the propositions must be convertible. For it has been shown in the book of Prior Analytics that if one thing is laid down, another does not follow of necessity, whether the thing laid down be one term or one proposition. For every syllogism must start with three terms and two propositions as a minimum. Therefore, in a circular demonstration three terms which are convertible must be taken, namely, A, B, C, such that A is in every B and in every C, and these, namely, B and C, must inhere in each other, so that every B is C and every C is B, and also inhere in A so that every A is B and every A is C. And so, the terms being thus related, it is possible, when using the first figure, to derive any one from any two circularly, i.e., the conclusion from two premises and each premise from the conclusion and the remaining premise, as we pointed out in the Prior Analytics, where we treated the syllogism formally.

The way it is done is this: take the three convertible terms, “risible,” “rational mortal animal” and “man,” and form the syllogism:

Every rational mortal animal is risible;

Every man is a rational mortal animal:

Therefore, every man is risible.

Then from the conclusion it is possible to conclude both the major and the minor; the major thus:

Every man is risible;

But every rational mortal animal is a man:

Therefore, every rational mortal animal is risible

and the minor thus:

Every risible is a rational mortal animal;

But every man is risible:

Therefore, every man is a rational mortal animal.

However, it has also been proved in the Prior Analytics that in figures other than the first, namely, in the second and third, one cannot form a circular syllogism, i.e., one through which each of the premises can be syllogized from the conclusion; or if one is formed, it is done not by using the premises already used but by using propositions other than those which appear in the first syllogism.

That this is so is obvious. For the second figure always yields a negative conclusion. Consequently, one premise must be affirmative and the other negative. However, it is true that if both are negative, nothing can be concluded; and if both are affirmative, a negative conclusion cannot follow. Therefore, it is not possible to use the negative conclusion and the negative premise to obtain the affirmative premise as a conclusion. Hence, if this affirmative is to be proved, it must be proved through propositions other than the ones originally used. Again, in the third figure the only conclusion ever obtained is particular. However, at least one premise must be universal; furthermore, if either premise is particular, a universal cannot be concluded. Hence it cannot occur that in the third figure each of the premises can be syllogized from the conclusion and the remaining premise.

For the same reasons it is obvious that such a circular syllogism (through which each premise could be concluded) cannot be formed in the first figure except in the first mode, which is the only one that concludes to a universal affirmative. Furthermore, even in this mode the only case in which a circular syllogism could be formed such that each of the premises could be concluded, is when the three terms employed are equal, i.e., convertible. The proof is this: The premise must be concluded from the conclusion and the converse of the other premise, as has been stated. But such a conversion of each premise is impossible (for each is universal), except when the terms happen to be equal.

—St. Thomas Aquinas's Expositio Posteriorum, lib. 1 l. 7 et 8

Therefore, contrary to the atheist scientists who nihilistically think doubt is the supreme intellectual virtue—even though they are correct that humility is good, just not the sort they conceive as devaluing human life, which is really denying the reality of the sacredness of life—we can see the necessity of belief in the ultimate principles upon which science bases itself. If "faith is more certain than science and the other intellectual virtues" (Summa Theologica IIª-IIae q. 4 a. 8), then science—especially the supreme science of theology that unifies all others—is possible because "demonstration must be based on premisses prior to and better known than the conclusion," as Aristotle said above.

I have claimed that science, a handmaiden of theology, is grounded not only by reason but also by faith—i.e., faith that knowledge of God from the created world (Romans 1:20) is possible through the senses because God's grace builds on our human nature. "[F]aith is the substance of things to be hoped for, the evidence of things that appear not" (Hebrews 11:1); it is an intellectual assent; it "is a kind of knowledge, inasmuch as the intellect is determined by faith to some knowable object" (Summa Theologica Iª q. 12 a. 13 ad 3). I do not mean that with sola fide (faith alone) one obtains intellectual knowledge as a fideist, one who agnostically "affirms that the fundamental act of human knowledge consists in an act of faith" and "denies intellectual knowledge," maintains (Sauvage, G.); no, intellectual knowledge comes from the senses (Nihil est in intellectu quod non prius in sensu.). St. Thomas the Apostle, through his desire to know, had faith that he could, and Christ, knowing that humans obtain intellectual knowledge via the senses, told him physically to touch Him, and he believed. For the same reason, Christ instituted the sacraments, physical signs of an invisible reality.

If, however, the lower sciences are indeed handmaidens of theology (Summa Theologica Iª q. 1 a. 5 s.c.), unified in this study of God, the supreme science, and if the "articles of faith" afford knowledge of God and His revealed truths for theology to adopt as its principles (Summa Theologica Iª q. 1 a. 7 c.), then why does it seem the truths of theology do not help the lower sciences like physics, chemistry, and biology, or vice versa? If they would—were modern science, far from being true science, not generally atheistic—then the ultimate source of all the sciences' principles would be the "deposit of faith," Revelation. But how? How do these truths from Revelation come to us as a result of having faith? They still come through the senses, except in very rare visions "accompanied by abstraction from the senses" (Summa Theologica IIª-IIae q. 173 a. 3).

On the necessity of believing things which can be proven by natural reason, St. Thomas says

It is necessary for man to accept by faith not only things which are above reason, but also those which can be known by reason: and this for three motives. First, in order that man may arrive more quickly at the knowledge of Divine truth. Because the science to whose province it belongs to prove the existence of God, is the last of all to offer itself to human research, since it presupposes many other sciences: so that it would not be until late in life that man would arrive at the knowledge of God. The second reason is, in order that the knowledge of God may be more general. For many are unable to make progress in the study of science, either through dullness of mind, or through having a number of occupations, and temporal needs, or even through laziness in learning, all of whom would be altogether deprived of the knowledge of God, unless Divine things were brought to their knowledge under the guise of faith. The third reason is for the sake of certitude. For human reason is very deficient in things concerning God. A sign of this is that philosophers in their researches, by natural investigation, into human affairs, have fallen into many errors, and have disagreed among themselves. And consequently, in order that men might have knowledge of God, free of doubt and uncertainty, it was necessary for Divine matters to be delivered to them by way of faith, being told to them, as it were, by God Himself Who cannot lie.

—Summa Theologica IIª-IIae q. 2 a. 4 co.

The Italian writer and apologist Alessandro Manzoni (1785-1873) said this about faith, which really reminds me of what is happening in science where it meets with Catholic morality; true science always conforms to true faith:

Have you examined all these objections [against Revelation]? Objections of fact, of chronology, of history, of natural history, of morals etc. Have you discussed all the arguments of the adversaries, have you recognized their falsity, unfoundedness?... this is not enough to have faith in Scripture. It is possible, it is unfortunately possible that in the generations to come... there will be some men who will study new arguments against the truths of the Scriptures; they will rummage through history, ... they will pretend to have discovered truth of fact for which the things affirmed in the Scriptures have to appear false. Now you must swear that these arguments that are not yet found, will be false, that these books that are not yet written, will be full of error: do you swear it? If you deny it, you admit to not having faith.

—Alessandro Manzoni's Morale cattolica, vol. II, pp. 544-545 [my translation]

If one understands this, then one can understand why Pope Paul VI—the pope of the controversial encyclical Humanæ Vitæ which correctly condemned as immoral any form of contraception—would advocate St. Thomas Aquinas's "perennial philosophy" for anyone seeking truth, including, e.g., modern physicists:

[...] to be a faithful disciple of St. Thomas today, it is not enough to want to do in our time and with the means available today that which he did in his. Contenting oneself with imitating him, like walking on a parallel street without anything to draw from him, one would with difficulty arrive at a positive result or, at least, offer to the Church and to the world that contribution of wisdom which they need. One cannot, in fact, speak of true and fecund loyalty if one does not receive, almost from his own hands, his principles which also illuminate the most important problems of philosophy and, to be more precise, to understand better the faith in these our times and, similarly, the fundamental notions of his system and the force of his ideas. Only so, the thought of the Angelic Doctor, confronted always with new contributions of profane science, will meet—through a sort of mutual osmosis—a new, thriving, lively development.

—Pope Paul VI's 1974 letter Lumen ecclesiæ 29. [my translation]

Hence, in light of all we have said, one must indeed have faith in order to come to a fuller understanding.

Government Intervention & True Science

Science is not as objective as those "Blinded by Scientism" may think or those who are "Recovering Sight After Scientism" are beginning to think. What it can understand is limited—either beneficially or not—by its premises and underlying philosophy (Parvus error in principio magnus est in fine.). Government intervention can adversely affect science, too. This is an example of how false premises, philosophies, and government intervention can hurt true science:

In February 2003, Dr. Louise Brinton, the National Cancer Institute's chief of the Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, served as chairperson at an NCI workshop in Bethesda, Md., to assess whether abortion was implicated as a breast cancer risk.

In the opinion of "over 100 of the world's leading experts," said the subsequent NCI report, including Dr. Brinton, the answer was no.

One expert disallowed from participating was Dr. Joel Brind, a biology and endocrinology professor who had co-authored a meta-analysis demonstrating an abortion/breast cancer (ABC) link.

Brind protested that the outcome was predetermined by "experts" handpicked by Dr. Brinton who either were not really experts, were dependent on the NCI or other government agencies for grants, or were pro-abortion extremists, such as two who had previously provided paid "expert" court testimony on behalf of abortionists.

Studies concluding there was not an ABC link were included in the workshop analysis; studies concluding there was were not.

At the time, 29 out of 38 studies conducted worldwide over 40 years showed an increased ABC risk, but the NCI workshop nevertheless concluded it was "well established" that "induced abortion is not associated with an increase in breast cancer risk."

Brind went on to write a minority report NCI alludes to on its website without publishing or listing its author and did not even mention in its workshop summary report.

Life went on, except for post-abortive women inflicted with breast cancer anyway.

But six years later something happened. Dr. Brinton either flipped her lid, flipped ideologies, restudied the evidence and decided to recant, or couldn't sleep at night – and she began righting her wrong.

In April 2009, Brinton co-authored a research paper published in the prestigious journal Cancer Epidemiology, Biomarkers and Prevention, which concluded that the risk of a particularly deadly form of breast cancer that attacks women under 40 raises 40 percent if a woman has had an abortion.

The paper's subtitle listed Brinton's position at NCI.

Curiously, the paper included as corroboration two studies Brinton's 2003 NCI "experts" had rejected. More curiously, it turns out Brinton co-authored one of those two studies.

For nine months, that little bombshell of a disaster for pro-abortion ideology was published without the NCI acknowledging it or changing its stance.

Then this month, Brind spotted and wrote about Brinton's concession and NCI's hypocrisy.

Now that the mainstream media's interest has been slightly piqued, NCI and Brinton are on the hot seat.

The Globe and Mail, Ontario's liberal news source, wrote Jan. 8:

An e-mail to Dr. Brinton on Friday was returned by an Institute spokesman named Michael Miller who said: "NCI has no comment on this study. Our statement and other information on this issue can be found at http://www.cancer.gov/cancertopics/ere." That link turns up a 2003 document that says a workshop of more than 100 leading experts concluded that having an abortion or miscarriage does not increase a woman's subsequent risk of developing breast cancer.

Requests for an explanation of the apparent discrepancy between that position and the information contained in the study released last spring went unanswered by NCI. …

[T]rying to prevent abortions by scaring women with breast cancer would truly be wrong. But so too would be suppressing the risks of abortion or any medical procedure.

A blogger at About.com, owned by the New York Times Company, wrote Jan. 8:

… Brinton admits that abortion raises breast cancer risk by 40 percent. Brinton spearheaded the 2003 NCI workshop about the abortion-breast cancer link. … That workshop made every effort to assure women that having induced abortions was not linked to an increased risk of breast cancer, and that research did not support an ABC link. Now NCI, usually a trusted institution, is telling us that there is a 40 percent risk increase for women who have had abortions. …

I just wish agencies like the NCI would get their story straight, so we have as much information as possible, to reduce our risk of breast cancer.

Pro-aborts are understandably mum about Brinton's concession. Confirmation of the ABC link would eviscerate public acceptance and participation in abortion. Exposure of a long-term cover-up would eviscerate the savings accounts of abortionists and the abortion industry following lawsuit losses of a magnitude as great as or greater than the class-action lawsuits against tobacco companies.

Only pro-abortion blogger RabbleProChoice dared to consider the ramifications, writing after reading Brind's revelation she was "shaken" after considering "what it could mean for the pro-choice movement." Rabble went on to "spen[d] almost my entire day" looking for reassurance, finding it at the American Cancer Society's website – the 2003 NCI workshop results!

Rabble nonsensically concluded that Brinton's 2009 study was "[j]ust more bad science from the anti-choice media machine."

Rather, it has been, all along, the pro-abortion media machine spewing out bad science to prop abortion.

Finally, someone has thrown a long overdue monkey wrench into the denial machinery.

—Jill Stanek's "Top scientist finally admits abortion-breast cancer link"

Existentialism Yields False Science

[...] when a learned man is presented with any statement in an ancient author, the one question he never asks is whether it is true. He asks who influenced the ancient writer, and how far the statement is consistent with what he said in other books, and what phase in the writer's development, or in the general history of thought, it illustrates, and how it affected other writers.

—C. S. Lewis, The Screwtape Letters

Is this how we perceive the writings of ancient scientists? In their historical context? Were they not striving to attain an absolute truth about the universe, or only a truth bound-up in the milieu of their era and Kuhnian paradigms? The latter would be true if one adopted the philosophy of evolutionism, viz., as Sartre said in his Existentialism is a Humanism lecture, "that man first of all exists, encounters himself, surges up in the world—and defines himself afterwards," irrespective of a guiding authority for judging truth. This conception of man is untrue since we do not invent truth and arbitrarily assign it a meaning ourselves; an objective, unchanging Reality exists outside ourselves in which is unified all truth into an infinitely simple Unity. This Reality is God, and only God gives us our meaning and dignity.

Four years after Sartre's lecture, Pope Pius XII wrote Humani Generis saying this about existentialism and how it leads to "false science":

Such fictitious tenets of evolution which repudiate all that is absolute, firm and immutable, have paved the way for the new erroneous philosophy which, rivaling idealism, immanentism and pragmatism, has assumed the name of existentialism, since it concerns itself only with existence of individual things and neglects all consideration of their immutable essences. [...] [The] Teaching Authority [of the Church] is represented by them [e.g., the existentialists] as a hindrance to progress and an obstacle in the way of science. [...] [And] [t]hese and like errors, it is clear, have crept in among certain of Our sons who are deceived by imprudent zeal for souls or by false science.

So, existentialism "concerns itself only with existence of individual things and neglects all consideration of their immutable essences." What scientists would reject, e.g., that the fundamental nature of proton seconds after the Big Bang is entirely different than it is now? Sure, physical constants could change over time, but unless there is some immutable kernel—such as the rational soul is for a human—you cannot have a coherent understanding of nature thus neither a coherent science. A proton a thousand years ago could be what we now call a unicorn.

Maintaining Catholic values amidst a culture so opposed to these values is the biggest challenge today facing not only scientists but everyone. Myriads of conflicting ideologies inundate us, and existentialists see the Catholic faith as just one of many seemingly equally true belief systems that man invented. Yet, man did not invent the Catholic Church, the most trustworthy, true, and immutable religion. God Himself, the immutable Word Incarnate, founded it out of love for us. Thus, the Catholic faith is a steady rock in the torrential sea of ideologies on which we can find hope, deepen our faith, and ultimately be charitable to both neighbor and God.

Those who seek a "Grand Unified Theory" of the universe ultimately seek to know God, who "became all things to all men" (1 Cor. 9:22) to "give testimony to the truth" (Jn. 18:37) so we can "have the unction from the Holy One, and know all things." (1 Jn. 2:20).

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.