On Faith and Reason: A Thomistic Account, Part I

“Faith is the great cop-out, the great excuse to evade the need to think and evaluate evidence. Faith is belief in spite of, even perhaps because of, the lack of evidence” [1].

This definition of faith, from the popular “new atheist” writer Richard Dawkins, describes what has become in the contemporary world a commonly assumed understanding of religious belief. “Faith” and “reason” are viewed as diametrically opposed. One involves thinking, evidence, rationality; the other is a blind acceptance, mindless, ignorant. One involves coming to an honest conclusion based on available information; the other involves clinging to unsupported beliefs without any sort of intellectual or factual justification, even if the actual data contradicts that belief. One is about science, knowledge, and discovery; the other is about religion, myth, suspicion. Faith and reason are opposing and incompatible stances, mutually exclusive of each other.

Or, at least, that is what we are often told; and is indeed what many today, both religious and skeptical, actually think. For example, in his book The God Delusion, Richard Dawkins writes: “One of the truly bad effects of religion is that it teaches us that it is a virtue to be satisfied with not understanding” (emphasis mine) [2]. And elsewhere:

“What is really pernicious [about religion] is the practice of teaching children that faith itself is a virtue. Faith is an evil precisely because it requires no justification and brooks no argument. Teaching children that unquestioned faith is a virtue primes them — given certain other ingredients that are not hard to come by — to grow up into potentially lethal weapons for future jihads or crusades” [3].

From this understanding of the negative relationship between faith and reason has arisen the somewhat widespread notion that it is the skeptic, the unbeliever, the atheist, who is really of intelligence, who actually thinks carefully and deeply about important matters and is honest enough to admit that he doesn’t know; while those who are religious are either uneducated, ignorant, or else merely compartmentalizing their faith and their intellectual life in separate and distinct spheres of reality. On this view, to seriously think is to cease to believe.

In this post, I’d like to suggest that the supposed conflict between faith and reason is really rather a false dichotomy, a modern fiction with no basis in reality that results from a drastic misunderstanding not only of faith but also of reason.

However, the error is not merely on the part of those who hold that faith is something essentially unreasonable and irrational; it is also on the part of those serious believers, especially many apologists, who pass to the contrary extreme in contending that faith is something entirely reasonable and rational. Both positions are mistaken.

To begin our analysis, we must examine the human person, specifically to discover what exactly it is which we customarily call “reason.” The human being, as Aristotle insightfully informs us, is by nature a rational animal. He is an animal because he is living, self-moving, reproducing, and has powers of sense-perception. But he is distinct from all the other species of animals in that he has a rational principle; in his ability to reason, think, know, and understand, man is alone amongst all beasts.

But what exactly do we mean by reason? In the above quotes from Dawkins, it appears that he takes “reason” (as a noun) to be something akin to epistemic justification for a position. This would fit his definition of faith as that which lacks justification, thought, and argument or support. On this view, both faith and reason are cognitive faculties which hold some proposition as true; but faith holds this without any actual grounds or vindication, without any foundation or logical connection to reality. “Reason” on this view is whatever serves as epistemic justification, and “reasoning” would presumably be the process of reaching some conclusion on the basis of such epistemic justification.

But it seems obvious that there can be, and are, various degrees and kinds of epistemic justification. Consider, for example, the following statements:

  • A whole is greater than its part
  • The tree I see in front of me actually exists
  • All men are bipeds
  • Socrates is mortal
  • The sun will rise tomorrow
  • China (a country I have never visited) exists
  • The earth is 92.96 million miles away from the sun

Each of these propositions, arguably, has epistemic justification and hence it is reasonable or rational to affirm them as true. But the kind of justification each has is quite different; and not all of them, we will suggest, are really a result of “reason” in a strict sense.

The statement “a whole is greater than its part” is what Thomists would refer to as a first principle of thought, a self-evident truth which is known as soon as its terms are understood. In other words, as soon as one grasps what the term “whole” means, and the term “part,” it becomes self-evidently and necessarily true that “the whole is greater than its part.” One needs no real process of reasoning, no argument or demonstration, that the statement is true; one knows it immediately. A primary example of such first principles is the law of identity or of non-contradiction. These laws cannot properly be demonstrated, since any demonstration must presuppose and make use of them. And yet they are known more clearly and more certainly than any knowledge achieved by demonstration; they are indeed the foundation of all demonstrable knowledge. The epistemic justification for belief in such principles lies in our immediate intuition of their necessary truth.

Likewise, when one perceives some object in front of oneself, one believes automatically in the real existence of that object. When I see a tree out my window, I don’t go through a process of reasoning to conclude that the tree exists; I believe such immediately. There seems to be a certain analogical correspondence between the immediate intuition of first principles by the mind and the immediate intuition of external objects by the senses.

The statement “all men are bipeds” is not a direct observation of the senses, but neither is it entirely a demonstrated conclusion of premises; it is something in between these. It is a product of induction and general experience. We perceive that one man has two legs, and then another, and another; and these perceptions are all added to our memory and become experience. As Saint Thomas Aquinas states, “from remembrance many times repeated in regard to the same item but in diverse singulars arises experience, because experience seems to be nothing else than to take something from many things retained in the memory” [4]. From induction and experience we form a general or universal law, such as “all men are bipeds.”

The proposition “Socrates is mortal” is a demonstrated conclusion. From the premise that “all men are mortal,” in conjunction with the present observation that Socrates is a man, it is deductively proven or demonstrated that Socrates is mortal. For Saint Thomas, this kind of knowledge is properly called scientia, or scientific knowledge, and it is this kind of knowledge, as we shall see, to which the term “reason” truly belongs. 

We shall not go into so much detail for the remaining statements. “The sun will rise tomorrow” is again a probable conclusion of induction and experience, but one which deals specifically with application of principles to future occurrences, about which we lack any absolute certainty [5]. That China exists, though I have never personally been there, I take as fact on the overwhelming evidence of testimony or witness: books, articles, news reports, etc., from people who really have been there and who report of their own experience. And, finally, that the earth is 92.96 million miles away from the sun I accept on the basis of competent authority

A few remarks about this last point are in order. One might wonder how, exactly, it differs from the earlier proposition “Socrates is mortal,” which we labeled scientific knowledge. Is the conclusion of the distance between earth and sun not likewise scientific knowledge? In short, yes. In themselves, both propositions are instances of scientia because both are conclusions reached by reasoning from premises and principles. In particular, the proposition in question is reached by applying certain mathematical principles and calculations to physical observations. But the reason I have distinguished these two propositions is in reference to their epistemic relation to us. In theory, the knowledge which provides the basis for the conclusion concerning the distance from earth to sun is available to everyone. But, in fact, the vast majority of people do not learn this proposition by actually completing the calculations for themselves; rather, they learn it from authorities such as teachers or books or scientific articles. This is similar to our earlier observation about belief in the existence of some foreign country. For an extremely large portion of our knowledge, we rely on trusting the witness and authority of others, especially when we are young.

From our examination of these statements, a variety of different kinds of epistemic justification have emerged. There are truths which are self-evident and which we know immediately; there is knowledge which comes from sense-perception; there is induction and common experience and the general laws we form from them; conclusions arrived by reasoning from premises; and, finally, facts which we accept on the basis of witness, testimony, or competent authority.

It seems quite clear that these kinds of epistemic justification have varying degrees of certitude. For instance, knowledge of self-evident first principles is absolutely certain and cannot even in principle be doubted. However, knowledge which consists of common experience can and often does change when we gain new experiences. If, as an example, we had only ever encountered birds which fly, we might assume it a general rule that “all birds can fly.” But if we then came across birds such as penguins which are incapable of flight, we would have to alter or reject our rule to fit the new data. There is no “one size fits all” in terms of what counts as actual epistemic justification and hence rational support for a position.

But do all of these different kinds of epistemic justification actually constitute “reason”? Properly, no. Although today we often use the terms “reasonable” and “rational” to refer to a large variety of epistemically justifiable positions, in truth they have a very specific domain.

All should agree that reason seeks truth. But, in the words Pontius Pilate once proposed to Jesus of Nazareth, Quid est veritas? What is truth? Formally, truth is “adaequatio intellectus et rei” or “the conformity of thing and intellect” [6]. For instance, if my mind holds that “this car is red,” and the car in reality is actually red, then my mind has grasped something true, for it is been conformed to reality, to being. When the mind is conformed to being such that it grasps something true, there is said to be knowledge: “Knowledge of a thing is a consequence of this conformity; therefore, it is an effect of truth” [7]. As Saint Thomas further explains, truth is:

“the correspondence of being to the knowing power, for all knowing is produced by an assimilation of the knower to the thing known, so that assimilation is said to be the cause of knowledge” [8]. 

When the mind really grasps being (the way things actually are), it grasps truth; and when the mind grasps truth it has knowledge.

The “intellect” is that aspect or faculty/power of the human soul which possesses knowledge. The intellect tends toward truth as its object [9]. It is the perfection and fulfillment of the intellect to know truth, to grasp being: “The perfection of spiritual nature . . . lies in cognition of truth” [10].

As we’ve already seen, some knowledge the intellect can possess immediately, such as the first principles. This kind of knowledge we shall call understanding. Once again, this knowledge is necessary and self-evident. As soon as we read the proposition “a whole is greater than its part,” we know it is true automatically. Saint Thomas writes:

Understanding seems to indicate simple and absolute knowledge. And one is said to understand (intelligere) because in some sense he reads (legit) the truth within (intus) the very essence of the thing” [11].

In such understanding we intuit the truth of the thing [12]. Properly speaking, this process of understanding is not actually reasoning. Understanding is the perfection of the intellect; while reason, in fact, implies imperfection of intellect. For understanding is “simple and absolute knowledge,” while reasoning “denotes a transition from one thing to another by which the human soul reaches or arrives at knowledge of something else” [13]. Reason “is related to understanding as movement to rest” [14]. Reason “can arrive at perfect knowledge of truth only through a certain movement, in which they go from one thing to another, in order to reach knowledge of things unknown through those which are known” [15]. And further on Aquinas writes:

The act of reason, which is to move from one thing to another, and the act of understanding, which is to grasp truth directly, are related to each other as generation to existence and movement to rest” [16].

Reason, therefore, is a movement of the intellect from something which is already known to something as yet unknown. Hence reason implies imperfection because it requires that there is currently an absence or lack of knowledge in the intellect, and, as we’ve said, knowledge is the perfection of the intellect. 

This is precisely what argument or demonstration is. A demonstration starts from principles/premises which are already known and accepted, and from them derives new conclusions. In doing so, the demonstration effectively moves the intellect; and this is what the process of reasoning consists of. 

Consider the following example of an argument used by Aquinas in his commentary on Aristotle’s Posterior Analytics:

  1. When we observe the heavens, we see that the planets do not scintillate (twinkle), while stars do, because stars are much farther away from us than planets
  2. When I observe Venus in the sky, I notice that it does not scintillate
  3. Therefore, Venus must be a planet, not a star

At this time, the first premise would be taken as a general principle of physics or astronomy; it is known by all who study the science. However, suppose an astronomer goes out with his telescope one night and discovers a new object in the sky. At first, he does not know whether or not this new object is a star or a planet. He has an absence/lack of knowledge, an imperfection of the intellect. And yet, because he does know the principle that stars scintillate while planets do not, and because he observes that the object in question is not scintillating, he can reason to the conclusion that this object must be a planet. His intellect has thus moved from a lack of knowledge to an increase in new knowledge.

Now, according to Aristotle, there are different “grades” of reasoning depending on the certainty/strength of their premises which in turn arrive at different degrees of certainty in the conclusion. Reasoning in general requires argument; the argument which is most certain is the demonstratio or demonstration. Aristotle writes:

“It is a ‘demonstration’, when the premisses from which the reasoning starts are true and primary, or are such that our knowledge of them has originally come through premisses which are primary and true” [17].

The conclusion of a demonstratio must be certain and necessary; and such a conclusion is said to cause scientia, or “scientific knowledge.” Hence Aquinas, following Aristotle, defines a demonstration as a syllogism which produces scientific knowledge [18]. In numerous places Aquinas states that scientia is the proper “effect” of demonstratio.

Scientia is certain knowledge because, in a demonstration, if one knows that the premises are true, one will know that conclusion which follows is also true; and hence one will offer their full assent to the proposition in question. But, Aquinas notes, besides scientia there are other kinds of intellectual acts; for we cannot always reach the certainty of scientia.

A proposition is essentially a “joining or dividing” of concepts. The proposition “The car is green” joins the concept “car” with the “concept” green, affirming the latter of the former. But, as Saint Thomas says, “everything which is undetermined with reference to two things is not limited to one of them unless by something which moves it” [19]. The intellect is not necessarily determined to either affirming or denying the concept “green” of the concept “car,” because it is not a self-evident or necessary truth that every car is green. So something other than the mere proposition in itself must move the intellect in determining which extreme of the contradictory proposition it will accept, i.e. either “the car is green” or “the car is not green,” since both cannot be true.

Saint Thomas writes: 

“Sometimes, it [the intellect] does not tend toward one rather than the other, either because of a lack of evidence, as happens in those problems about which we have no reasons for either side, or because of an apparent equality of the motives for both sides. This is the state of one in doubt, who wavers between the two members of a contradictory proposition” [20].

Sometimes, we are presented with a proposition, and we do not have enough information to determine whether or not it is true. In such a case we are said to have doubt.

Aquinas continues:

Sometimes, however, the understanding tends more to one side than the other; still, that which causes the inclination does not move the understanding enough to determine it fully to one of the members. Under this influence, it accepts one member, but always has doubts about the other. This is the state of one holding an opinion, who accepts one member of the contradictory proposition with some fear that the other is true” [21].

So opinion is when evidence inclines our intellect to one side or another of an affirmation or denial of a proposition, but only slightly, and not to an extent that can be said to have actual knowledge. Suppose, for instance, a young boy is trying to figure out whether or not a girl likes him. Some signs suggest no: she does not always return his calls, she sometimes talks to other boys, etc. But some signs suggest the contrary: she often sits next to him in class, she is friendly to him, etc. In weighing the conflicting evidence, if the boy thinks both sides are about equal, he will have only doubt. But if he thinks one side is somewhat stronger, he will be of the opinion that the girl likes him; but he would hardly call it sure knowledge.

Scientia is when the intellect “is so determined that it adheres to one member without reservation” [22]. In scientia the intellect is thus determined by the “intelligible object” itself, by the recognition of the truth of the proposition either in itself or by way of demonstratio

There is one final kind of intellectual act which St. Thomas calls fides, or belief/faith. In the next post we shall explore fides and its relation to reason, to discover whether or not, contra Dawkins et al., faith can ever be rational/reasonable.




[1]. Richard Dawkins. ‘A Scientist’s Case Against God.’ Published in the Independent, 20 Apr. 1992. Quote found here: http://www.cis.org.uk/upload/Resources/Atheism/Poole_dawkins.pdf

[2]. Richard Dawkins. The God Delusion. Mariner Books 2008 edition. 152.

[3]. Ibid. 347-348.

[4]. Aquinas. Commentary on the Posterior Analytics of Aristotletranslated by Fabian R. Larcher, O.P. Re-edited and html-formated by Joseph Kenny, O.P. http://dhspriory.org/thomas/PostAnalytica.htm#220. Book II, Lectio 20.

[5]. See: Coffey, Peter. “Induction.” The Catholic Encyclopedia. Vol. 7. New York: Robert Appleton Company, 1910. 25 Jul. 2018 <http://www.newadvent.org/cathen/07779a.htm&gt;.

[6]. Aquinas. Quaestiones Disputatae de VeritateQuestions 1-9 translated by Robert W. Mulligan, S.J. Chicago: Henry Regnery Company, 1952. Html edition by Joseph Kenny, O.P. http://dhspriory.org/thomas/QDdeVer.htm. Q. 1, Art. 1.

[7]. Ibid.

[8]. Ibid.

[9]. “The true denotes that towards which the intellect tends.” Thomas Aquinas. Summa Theologiae. Translated by Fr. Laurence Shapcote, O.P. The Aquinas Institute for the Study of Sacred Doctrine, 2012. I, Q. 16, Art. 1.

[10]. Aquinas. Quaestiones Disputatae de VeritateQuestions 10-20 translated by James V. McGlynn, S.J. Chicago: Henry Regnery Company, 1953. Q. 15, Art. 1.

[11]. Ibid. 

[12]. Rahilly, Alfred. “Reason.” The Catholic Encyclopedia. Vol. 12. New York: Robert Appleton Company, 1911. 24 Jul. 2018 <http://www.newadvent.org/cathen/12673b.htm&gt;.

[13]. Aquinas. Quaestiones Disputatae de VeritateQuestions 10-20 translated by James V. McGlynn, S.J. Chicago: Henry Regnery Company, 1953. Q. 15, Art. 1.

[14]. Ibid.

[15]. Ibid.

[16]. Ibid.

[17]. McKeon, Richard, editor. The Basic Works of Aristotle. New York: Random House, Inc, 1941. Topics 1.1, 100a27-30.

[18]. Aquinas. Commentary on the Posterior Analytics of Aristotletranslated by Fabian R. Larcher, O.P. Re-edited and html-formated by Joseph Kenny. Book I, Lectio 4. 

[19]. Aquinas. Quaestiones Disputatae de VeritateQuestions 10-20 translated by James V. McGlynn, S.J. Chicago: Henry Regnery Company, 1953. Q. 14, Art. 1.

[20]. Ibid.

[21]. Ibid.

[22]. Ibid.

Other sources used: http://www.aquinasonline.com/Questions/science.html








4 thoughts on “On Faith and Reason: A Thomistic Account, Part I

    1. Yes, haven’t had much opportunity to keep up with the blog since the new semester started. I have a post almost finished, hopefully can get it posted soon and also reply to some of the comments I haven’t been able to get to


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