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“The Role of Dialectic in Liberal Education”


by Dr. Anthony P. Andres
Tutor, Thomas Aquinas College, California
St. Vincent de Paul Lecture & Concert Series
January 20, 2023


I would like first to thank the Lecture Committee for the honor of asking me to speak to you tonight and for giving me the opportunity to visit for the first time the beautiful New England campus of Thomas Aquinas College. I can clearly see that the tutors and students here have been entirely faithful to the founder’s vision of Catholic liberal education.

That vision of Catholic liberal education was not an invention of theirs but was the recovery of a form of education that had its beginnings in the Academy of Plato and reached its perfection in the Catholic universities of the Middle Ages. It is a tradition that dominated higher education up to the end of the 18th Century, when it was destroyed in France by the Revolution and largely destroyed in the rest of Europe because of the Napoleonic Wars.

That tradition has always included the study of the dialectical method, a study omitted from modern schemes of higher education. The purpose of my lecture tonight is to argue that dialectic plays an important role in liberal education and to explain what that role is. I will do that first by briefly explaining what both liberal education and dialectic are. Then I will look at two views about the role of dialectic in liberal education, one that I think gives it too prominent a place, and the other which neglects it altogether. Finally, I will discuss the correct and moderate view, that of Aristotle, on the place that dialectic ought to have in liberal education.

Liberal Education

The word 'liberal' comes from the Latin for free, and so it makes sense to say that a liberal education is the education appropriate to the free man. We tend to think about this freedom in a superficial way; we think that a man is free when he is not restricted by rules, not hampered by responsibilities; we think that the free man has lots of free time and can do whatever he pleases. But Aristotle, living in a society in which slavery was just as common as freedom, saw that the opposite was the case: free men were burdened with responsibilities and left with little free time.

So, if free time and a lack of restrictions are not the marks of the free man, what is it that really distinguishes him from the slave? It is that the free man lives for his own sake and directs himself in his important actions. In contrast, the slave lives for the service of another and in the important actions of his life is ruled by another man. A liberal education, then, is the education that is appropriate to a man who is free in this sense of the term.

Since learning is the point of any education, we need to ask what it is appropriate for a free man to learn. Clearly, he needs to learn those sciences which teach a man how to live well. Ethics and politics, therefore, are necessary parts of a liberal education. But since he lives for his own sake, he also wants to study those sciences which are worth knowing for their own sake, such as philosophy and Sacred Theology. Liberal education leaves aside disciplines such as engineering and agriculture; useful as they are, they are not worth knowing for their own sake, but only for the sake of the bridges that they build or the crops that they grow. Theology, philosophy, both speculative and moral, and mathematics form the chief parts of a liberal education.

But besides these the ancient tradition includes the seven liberal arts, seven disciplines that prepare the student to the study of the highest things. The seven are divided into two groups: the quadrivium, which includes arithmetic, geometry, astronomy and music; and the trivium, which includes grammar, rhetoric and logic. Logic is the most important discipline in the trivium, and dialectic has a prominent place in the study of logic. In fact, in some versions of the tradition, dialectic was thought to be the most important part of logic, so much so that the name ‘dialectic’ replaced the name ‘logic’ in some lists of the liberal arts.


The word ‘dialectic’, which is related to the word ‘dialogue,’ names a method of proceeding in intellectual inquiry. Let’s look at one of Plato’s dialogues, the Meno, and count out the main features of Socrates’s method.

The Meno begins, you might recall, with Meno challenging Socrates to tell him whether virtue is teachable. Socrates replies that he does not even know what virtue is, an admission that shocks Meno, and prompts him to offer his own definition. Socrates then questions him about his definition, and Meno is forced to modify his definition again and again until he finally admits, not that he does not know what virtue is, but that for the moment he is unable to explain it to Socrates. What I want to point out here is that this dialogue shows us all the main features of the dialectical method.

Feature #1: Socrates does not make assertions, does not explain his own views, does not answer questions; Socrates asks questions. But his questions are neither random nor open-ended; he asks an orderly series of yes-no questions for which he expects particular answers. The following is a typical example: (73a-73c)

SOCRATES: Were you not saying that the virtue of a man was to order a state, and the virtue of a woman was to order a house

MENO: I did say so.

SOCRATES: And can either house or state or anything be well ordered without temperance and without justice?

MENO: Certainly not.

SOCRATES: Then they who order a state or a house temperately or justly order them with temperance and justice?

MENO: Certainly.

SOCRATES: Then both men and women, if they are to be good men and women, must have the same virtues of temperance and justice?

MENO: True.

SOCRATES: And can either a young man or an elder one be good, if they are intemperate and unjust?

MENO: They cannot.

SOCRATES: They must be temperate and just?

MENO: Yes.

SOCRATES: Then all men are good in the same way, and by participation in the same virtues?

MENO: It seems so.

But how can Socrates anticipate what the answers will be? The answers are all in accord with the opinions men commonly hold on these matters. It would be ridiculous to say the opposite: it would be ridiculous to say that men direct the city well, but not justly; it would be even more ridiculous to say that they direct it justly despite not being just; and it would be most ridiculous to say that men and women were not good in the same way despite the fact that they become good by sharing the same qualities. So the secret to Socrates’s success is like that of a good lawyer: he only asks questions that he already knows the answers to. And he can do this because he is asking Meno to agree to common opinions about the matter at hand.

Feature #2: Socrates does not first aim to prove propositions, but more to refute them. For example, once Meno is convinced that the definition of virtue needs to be one, he offers the following account: “virtue is desiring fine things and being able to acquire them” (77b). Socrates then asks Meno a series of questions, and by the end he complains to Meno: “So it follows from your own statements that to act with a part of virtue is virtue.” That is, he is pointing out to Meno that his definition is circular. By asking the right series of questions he has elicited from Meno a series of statements which, when put in order, provide a refutation of Meno’s initial position.

Feature #3: Socrates is especially concerned with definitions. For example, the dialogue begins with Meno asking a question: “Can you tell me Socrates, is virtue something that can be taught?” Socrates deflects the question is a way that surprises Meno: he admits that, far from knowing whether virtue can be taught, he does not even know what it is. And he asks, “How can I know the property of something when I don’t even know what it is?” Socrates here makes the point that the knowledge of the nature of a thing is prior to the knowledge of its properties. And since the nature is expressed by a definition, when he asks Meno what virtue is, he is asking him for the definition of virtue. This question from Socrates, which begins the real business of the dialogue, is the only open-ended question that he asks, and its answer, a definition, is the target of the refutation which the method of Socrates produces.

Feature #4: Socrates can argue to both sides of a question. After he has convinced Meno that it is not pointless to seek to learn, Meno insists that Socrates take up his initial question of whether virtue can be taught. Socrates reluctantly agrees, and first asks a series of questions which ends with the conclusion that virtue can be taught. But Socrates is uneasy and consequently initiates another series of questions which leads to the conclusion that virtue cannot be taught. And this makes it manifest that the dialectical method can be used to argue to both sides of a disputed position.

So, let’s sum up the chief features of the dialectical method as displayed in the Meno. First, the user of the dialectical method asks questions. He does not ask just any questions, but those questions whose answers are the common opinions of mankind. Second, most often he uses those answers to construct a refutation of the initial opinion of his partner in conversation. Third, he refutes definitions, especially the definitions concerned with our most important conceptions about life and reality. Fourth, when he does argue for a position, he can also use his method to argue against it. These are the four features constitute our first account of the nature of the dialectical method.

And so we come to our next question: How important is the use of the dialectical method in liberal education? Is it all important, as Plato seems to think? Is it not important at all, as the modern philosophers, Bacon and Descartes, think? Or does its importance rank somewhere in between? To start to answer this question, let’s look first at Plato, then at Descartes, and see what role they think dialectic plays in the intellectual life and, most importantly, the role they think that it plays in philosophy.

Two Extremes

At one extreme is Plato, who almost identifies dialectic and philosophy. In the Republic he writes:

In the same way, whenever someone tries through argument and apart from all sense perceptions to find the being itself of each thing and doesn’t give up until he grasps the good itself with understanding itself, he reaches the end of the intelligible. . . . And what about this journey? Don’t you call it dialectic?[1]

Here Plato is telling us that dialectic is the journey of the soul, the road over which the soul travels, when it leaves behind the senses and grasps more and more intelligible realities until it reaches the ultimate intelligible reality, the form of the good. And when Plato compares dialectic to the other subjects studied by the guardians of the Republic, he concludes that “dialectic is placed at the top of the other subjects like a coping stone, and no other subject can rightly be placed above it.”[2] Plato makes dialectic identical with philosophy.

If that is correct, then wisdom cannot possibly be grasped without using dialectic, and a dialectical inquiry is all anyone needs to achieve wisdom. Thus by Plato’s account dialectic is both a necessary and a sufficient method for the study of philosophy.

The great modern mathematician and philosopher, Descartes, not only denied that dialectic was sufficient, he also denied that it was even necessary. In fact, he argued that dialect is an obstacle to philosophy, that the dialectical method should be banished. In his Rules for the Direction of the Mind he writes:

In the subjects we propose to investigate [and this includes philosophy], our inquiries should be directed, not to what others have thought, nor to what we ourselves conjecture, but to what we can clearly and perspicuously perceive and with certainty deduce; for knowledge is not won in any other way.[3]

Descartes here is telling us that an inquiry beginning with what others tend to think, what we naturally tend to think, can never help us acquire knowledge. Only an inquiry beginning with the clear grasp of definitions, postulates and common notions and deducing unshakeable conclusions is a way to knowledge. Only the mathematical method, which we see used by Euclid, succeeds, while Plato’s dialectical method fails, and so dialectic should be banished from philosophy.

Aristotle on the Dialectical Syllogism

Aristotle, we are going to see, takes a middle road with respect to the dialectical method. We can begin to see this by noticing that Aristotle wrote five treatises in the branch of philosophy we now call logic: Categories, On Interpretation, Prior Analytics, Posterior Analytics, Topics, and Sophistical Refutations. Those five constitute over 15% of his extant works, and the longest among them is the Topics, his treatise on the dialectical method. So clearly Aristotle did not banish the dialectical method from philosophy.

Yet it is also clear that he did not regard the dialectical method as the principal philosophical method. In the Prior Analytics Aristotle explains what he means be a syllogism: “a syllogism is discourse in which, certain things being stated, something other than what is stated follows of necessity from their being so.” And then at the beginning of the Posterior Analytics Aristotle tells us that one kind of syllogism, the demonstrative syllogism, is the principal method of obtaining philosophical knowledge: “What I now assert is that at all events we do know by demonstration. By demonstration I mean a syllogism productive of scientific knowledge, a syllogism, that is, the grasp of which is in itself such knowledge.” And at the beginning of the Topics Aristotle makes a sharp distinction between the demonstrative syllogism and the dialectical one. He writes:

Now syllogism is discourse in which, certain things being laid down, something other than these necessarily comes about through them. It is demonstration when the premises of the syllogism are true and primary or are such that our knowledge of them has come through premises which are true and primary. A syllogism, on the other hand, is dialectical if it reasons from opinions that are generally accepted.

He further distinguishes the premises of demonstration from those of dialectic as follows:

Premises are true and primary which are believed on the strength, not of anything else, but of themselves. . .. Each of the first principles should command belief in itself. On the other hand, the generally accepted are those accepted by all, by most, or by the wise, and another these, by all, most or the most notable of them.

And finally, in the Prior Analytics Aristotle notes a further difference between the dialectical and demonstrative premise:

The demonstrative premise differs from the dialectical because the demonstrative premise is the assertion of one of two contradictory statements. The demonstrator does not ask for his premise but lays it down, whereas the dialectical premise is an asking for one of two contradictories.

So, we can sum up his view of dialectic as follows. Both dialectic and demonstration use a syllogism as defined in the Prior Analytics, discourse in which, certain premises being given, the conclusion follows by necessity because of them, but the character of the premises and the conclusion differ. Demonstration lays down premises that are true and primary, that is, such that they command belief in themselves. It then produces scientific knowledge of its conclusion. In fact, Aristotle goes so far as to say that the grasp of the syllogism in itself constitutes scientific knowing. Thus, demonstration is clearly the philosophical method par excellence.

Dialectic, in contrast, has to ask for its premises, and the premises that it receives do not command assent in themselves, but only because they are generally accepted opinions, either of all men, or most, or the wise. And so our grasp of the conclusion of a dialectical demonstration does not constitute knowledge. Rather, at best the dialectical syllogism produces an opinion.

So Aristotle, like Descartes, points out for us a method other than dialectic for obtaining true philosophical knowledge. His method does not ask for assent to its premises, but simply lays them down; his does not seek refutation, but chiefly seeks to establish conclusions; and his does not argue to both sides of a question, but only to the true side. Yet, unlike Descartes, Aristotle does not banish the dialectical method from philosophy, but instead writes a long book, the Topics, that aims to bring that method to perfection. Our next task is to see why he does so.

The Uses of Dialectic

Aristotle identifies three things for which the study of the Topics is useful. Dialectical reasoning, although it falls short of demonstration, is still an exercise that sharpens the mind, and the exercise becomes more beneficial when we have a method of carrying it out, a method this treatise supplies. The method also makes the student better able to engage in discussion because it enables him to meet his interlocutor on the interlocutor’s own ground. But most importantly, Aristotle maintains that the method laid out in this treatise is useful to the philosophical sciences.

How can a method which does not give knowledge be helpful to philosophy? Aristotle lays out two ways. First, the student trained in dialectical reasoning is able to raise difficulties on both sides of any question, and the one who sees the difficulties is better able to discern which side is true and which false. Second, the student of dialectic is better able to discuss the first principles of the sciences. Aristotle writes:

Dialectic has a further use in relation to the first principles of each science. For it is impossible to discuss the principles at all from what is proper to the science, since the principles are the first of all things. It is through what is generally accepted that the principles have to be discussed, and this is proper and belongs most of all to dialectic. For dialectic is a process of criticism wherein lies the path to the principles of all sciences.

Aristotle points out, quite rightly, that no science can dispute about its own principles. The reason is that a disputation requires an appeal to premises which are prior to the issue under debate. But the first principles of a science have nothing that come before them. Therefore, a science can dispute about its principles.

Dialectic, however, takes as its quasi-principles, not the true first principles of some science, but what is generally accepted, that is, the opinions men commonly hold on such matters. Therefore, in dialectic there is something that comes before the first principles, commonly held opinions. And so the dialectical method can be used to argue about the first principles.

We saw just above that Aristotle has said that we can use dialectic to discuss and dispute about the first principles of demonstration in the sciences. But before that he said that the first principles of the sciences command assent in themselves, not as the result of any kind of reasoning. That is, on the one hand he has said that the first principles are self-evident, and on the other that the first principles need to be disputed about. And what is worse, the disputation about the self-evident principles uses a method whose premises are only opinions, and so are far less certain than the first principles themselves. If this is the main use of dialectic in philosophy, dialectic does look almost useless, and Descartes seems to have been right to discard it.

More Intelligible in Itself and to Us

I think that the key to solving this problem is found by examining an unresolved difficulty posed by Aristotle in the second chapter of the Posterior Analytics. Demonstration, he notes, takes as premises statements which are true, primary, immediate, better known than and prior to the conclusion. But there is a difficulty:

Prior and better known are ambiguous terms, for there is a difference between what is prior and better known by nature and what is prior and better known to us. I mean that the objects that are nearer to sense are prior and better known to us, but what is prior and better known simply are those further from sense. Now the most universal causes are furthest from sense and particular causes are nearest to sense, and they are thus exactly opposed to one another.

And Aristotle sharpens the problem a little later in the same chapter:

Now since the required ground of our knowledge, of our conviction, of a fact is the possession of such a syllogism as we call demonstration, and the ground of the syllogism is the facts constituting the premises, we must not only know the primary premises beforehand, but know them better than the conclusion.

We can then restate the problem as follows. The premises of a demonstration must be prior and better known than the conclusion simply speaking. But our knowledge of the conclusion requires that the premises be prior and better known to us, since they are the cause of our knowledge of the conclusion. But what is prior and better known simply is opposed to what is prior and better known to us, because the former is farther from the senses and the latter is closer. Therefore, demonstration simply speaking seems to be impossible for human nature. If demonstration should turn out to be impossible, then our worries about the dialectical method would be pointless: knowledge would be impossible anyway.

Aristotle, I think, overcomes the difficulty in Book VI of the Topics. There he lays out the rules for refuting a definition, and the chief rule is this: “First of all, see if he has failed to make the definition through terms that are prior and better known.” That is, Aristotle is saying that a proposed definition can be refuted if the terms of the definition are not prior to and better known than the conclusion. That is because the chief task of the definition is to make its subject more known. A definition which is constructed from what is not prior and better known is a bad definition.

But in what sense are the parts of the definition supposed to be prior and better known than the subject defined, prior and better known to us or prior and better known by nature? Aristotle asserts: “It is clear, then, that the right way to define is not through terms of that kind [that is, more known to us], but through what is simply speaking more known: for only in this way could the definition come always to be one and the same.” That is, the terms in the definition must be prior and better known by nature than the term being defined.

We might think that this requirement makes definition impossible; Aristotle thinks otherwise. To solve the difficulty he makes a analogy between a sound state of understanding and a sound state of health: “Perhaps also, what is intelligible simply is what is intelligible, not to all, but to those who are in a sound state of understanding, just as what is healthy simply is healthy to those in a sound state of body.”

Let me draw out the analogy. Vigorous exercise is healthy simply speaking because it preserves the health of a body in good condition. But for a body in poor condition, vigorous exercise can be harmful. That is, what is healthy simply speaking is healthy to the sound body, but not to the sick one. Similarly, what is more intelligible in itself is also more intelligible to someone of sound understanding, to someone is “sharp witted,” but to someone whose understanding is not sound, what is more intelligible in itself is less intelligible to him.

Health and being sound-minded, however, differ in this way: most men are born with health and later fall into sickness, but no man starts out with a sound understanding and falls into weak-mindedness. Rather, for all men, what is more intelligible to them is first what is less intelligible by nature. Most men begin life unable to acquire scientific knowledge.

But the case is not hopeless. Aristotle also notes: “To the same people at different times different things are more intelligible, first of all the objects of sense; then, as they become more sharp-witted, the converse.” That is, Aristotle does not think that what is more intelligible, more known, to any particular man is necessarily always the same. Rather, he thinks that as a result of intellectual development what is more known by nature can become more known also to some particular man. Every man begins with an unsound mind, but some come to possess the sound mind for which what is more intelligible in itself is more intelligible to that mind.

Let’s see how this might happen in a couple of simple examples, first in a definition. It’s easy enough to define a triangle as Euclid does, through genus and specific difference, as a plane figure bounded by three straight lines. Most men, however, never reach such a distinct conception of the triangle, a conception of it through the principles of its intelligibility. Rather, their conception of the triangle is dominated by the sensible image of a triangle. Their intellects do not use the image; rather, their use of the word ‘triangle’ and the judgments that they make about triangles are governed by the phantasm contained in the imagination. But since the intelligible content is always there, it is possible by an exertion of the mind to reverse the situation, to use its images to conceive of the species through its genus and difference. And in this way what is more intelligible in itself becomes more intelligible to some particular man.

This is also true in the case of the propositions which are the first principles of science. We can begin to see that this is so by looking at the last common notion in Euclid, that the whole is greater than the part. Nothing could be more self-evident; even a toddler knows that it’s true. And yet, think about how the toddler knows it. He has never articulated the proposition “the whole is greater than the part,” and he wouldn’t understand you if you told it to him. What he really knows is that the whole slice of cake is better than part of one, that the whole candy bar is better than one bite of it. He does know the truth, but he only conceives of it in its particular application, it is always mixed up with his judgments about particular sensible objects. The toddler’s knowledge of the last common notion is not distinct and abstract enough to give it scientific vigor, to make it one of the true and primary principles of demonstration.

But after even just one semester of Euclid, that proposition, the whole is greater than the part, in its geometrical application, is luminously self-evident to you and possesses scientific vigor. How did this happen? Recall your first several Euclid classes. You discussed, you even argued about these primary premises. On what basis did you make your arguments? You could not have based them upon the principles of geometry; that is exactly what you were trying to understand. Rather, the bases of your arguments were probable opinions, things which you were naturally inclined to assert even though you did not have proof for them. In other words, you began the study of geometry with a dialectical consideration of its first principles.

And this solves the problem of the Posterior Analytics as well. The first principles of the sciences, when conceived through their principles of intelligibility, command assent in themselves. But these principles are either definitions, and so become intelligible in the same way that the definition does, or are known as soon as the terms are understood, and so their conception follows upon the conception of the definitions of the terms. In either case, the problem concerning our knowledge of the first principles is solved when we understand how, when something is defined, what is more intelligible in itself becomes more intelligible to the man of sound mind. It is because the man of sound mind can understand the definitions.

As I noted above, it seems appropriate that the solution to this problem is found, not in the Posterior Analytics, but in the Topics, because it is the job of the dialectician to refute proposed definitions through premises which are the commonly accepted opinions of men. The commonly accepted opinions of men are not more intelligible in themselves, but they are more intelligible to most men, closer to the senses, and thus the most appropriate starting point for pre-scientific inquiry. Dialectic tests definitions by trying to refute them and in the process uncovers the intelligible principles of the subject being defined. Thus, the exercise of dialectic is what strengthens the mind of a man so that it achieves that sound state of understanding in which what is more intelligible to him is more intelligible in itself. And so dialectic, far from being useless in philosophy, is chief preparation for it. In fact, most of your liberal education is undertaken according to a dialectical rather than a demonstrative method. So, far from being banished dialectic from liberal education, dialectic turns out to be the greatest, though not most important, part of it.


In conclusion, we can now sum up what role dialectic should play in a liberal education. The liberally educated man aims at scientific knowledge and wisdom, and demonstration is the method by which one attains these in their perfection. But the liberally educated man, as such, is one who has made a beginning in these things and has not necessarily achieved wisdom in its perfection. And the beginning of acquiring these things is made through a training of the mind by which it is strengthened, so that it frees itself from its domination by the sensible image and begins to conceive of things through their proper intelligibility. That is, the liberally educated man is one for whom what is more intelligible in itself has begun to be more intelligible to him. And since that happens through the use of the dialectical method, then dialectic must have a prominent place in a liberal education. Thank you for your attention.


[1] Republic VII, 532b

[2] 534e

[3] Rule III, p. 3


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