The Bodyguards of Truth – Mortimer J. Adler


My serious study of philosophy began when, at Columbia University in the early twenties, I took a course in the history of philosophy taught by Professor F.J.E. Woodbridge. Just before Christmas in 1921, I received as a Christmas gift, a copy of the Oxford translation of Aristotle’s Metaphysics, with an inscription from Professor Woodbridge that read as follows: “To Mortimer Adler who has already begun to make good use of this book.”

I owe to Professor Woodbridge, for whom, as for Thomas Aquinas, Aristotle was “the Philosopher,” my early sense of the number and variety of the truths that might be found by a careful study of Aristotle’s works, as well as a recognition of the soundness of Aristotle’s approach to philosophical problems and his method of philosophizing. But I owe to Thomas Aquinas, whose Summa Theologica I discovered a few years later, the instructive example of a powerful use of that method, together with the direction and guidance one needs not only in the study of Aristotelian philosophy, but also in the application of it to problems not faced by Aristotle himself.

With one or two exceptions, all the fundamental philosophical truths that I have learned in more than fifty years, to which I am now firmly committed, I have learned from Aristotle, from Aquinas as a student of Aristotle, and from Jacques Maritain as a student of them both. I have searched my mind thoroughly and I cannot find in it a single truth that I have learned from works in modern philosophy written since the beginning of the 17th century. If anyone is outraged by this judgment about almost four hundred years of philosophical thought, let him recover from it by considering the comparable judgment that almost all modern and contemporary philosophers have made about the two thousand years of philosophical thought that preceded the 17th century. In view of the fact that philosophy, unlike science, does not advance with each succeeding generation of men at work, it should not be deemed impossible, or even unlikely, that the first two thousand years of philosophical thought discovered a body of truths to which little if anything has been added and from which much has been lost in the last four hundred years.

Principles for the Correction of Error

The pre-modern career of philosophy contains errors as well as truths. As I have already intimated, the truths, for the most part, have been contributed by Aristotle and by Aristotelians. Even the tradition of Aristotelian thought is not without faults — deficiencies and errors. In the course of my own work as a student of Aristotle and Aquinas, I have, from time to time, uncovered such faults and tried to correct them. Such efforts on my part, may I say in passing, especially essays and books that criticized the traditional theory of species, the traditional view of democracy, and traditional formulations of the proofs of God’s existence, were not universally applauded in the late thirties and early forties by my fellow-members in the American Catholic Philosophical Association. Whether, if reviewed today, they would be differently appraised, I cannot say. To win tolerance for such fault-finding, I did try to say then, as I would say now, that in every case the correction of an error or the repair of a deficiency in the philosophy of Aristotle and Aquinas rests on the underlying and controlling principles of Aristotelian and Thomistic thought. In fact, the discovery of such errors or deficiencies almost always springs from close attention and leads to a deeper understanding of those principles.

Here lies what for me is the remarkable difference between the faults I have found in modern philosophy and the faults I have found in the tradition of Aristotelian and Thomistic thought. The errors and deficiencies in this or that modern philosopher’s thought arise either from his misunderstanding or, worse, his total ignorance of insights and distinctions indispensable to getting at the truth — insights and distinctions that were so fruitful in the work of Aristotle and Aquinas, but which modern philosophers have either ignored or, misunderstanding them, have dismissed. In addition, the errors or deficiencies in the thought of this or that modern philosopher cannot be corrected by appealing to his own most fundamental principles, as is the case with Aristotle and Aquinas. On the contrary, it is usually his principles — his points of departure — that embody the little errors in the beginning which, as Aristotle and Aquinas so well knew, have such serious consequences in the end.

To say, as I have said, that I have not learned a single fundamental truth from the writings of modern philosophers is not to say that I have learned nothing at all from them. With the exception of Hegel and other post-Kantian German philosophers, I have read their works with both pleasure and profit. The pleasure has come from the perception of errors the serious consequences of which tend to reinforce my hold on the truths I have learned from Aristotle and Aquinas. The profit has come from the perception of new but genuine problems, not the pseudo-problems, perplexities, and puzzlements invented by therapeutic positivism and by linguistic or analytical philosophy in our own century.

The genuine problems to which I am referring are questions that have been generated under the cultural circumstances characteristic of modern times, especially the effect on philosophy of its gradually recognized distinction from investigative science and from dogmatic theology, as well as the effect on it of certain developments in modern science and certain revolutionary changes in the institutions of modern society.

The profit to be derived from the perception of these problems (of which Aristotle and Aquinas were not aware or were only dimly aware) is the stimulus it gives us to try to extend their thought in response to them. I have always found that I could solve such problems within the general framework and in the light of the basic principles of their thought. They may not have faced the questions that we are obliged to answer, but they nevertheless do provide us with the clues or leads needed for discovering the answers.

Many years ago, in our early days together at the University of Chicago, my friend Professor Richard McKeon once quipped that the difference between the members of the American Philosophical Association and the members of the American Catholic Philosophical Association was that philosophers in our secular universities specialized in very good and novel questions, to which the scholastic philosophers did not yet have the answers, whereas the scholastics had a rich supply of true principles and conclusions but usually failed to be aware of many important questions to the answering of which they could be applied. My own experience has confirmed the wisdom as well as the wit of that observation. Let me illustrate the point by one example drawn from some work that I have been doing recently in political and economic philosophy, which concerns the relation of liberty and of equality to justice.

The following questions have, in various forms, pervaded the thinking of the last hundred and fifty years about liberty and equality. Of these two goods, the circumstantial freedom of individuals in society and the equality of conditions under which individuals may live in society, which is the supreme or sovereign value? Should individual freedom be encroached upon to establish a complete equality of conditions? Should inequalities of condition be allowed to remain if that is necessary to maximize individual freedom? Is there some way of reconciling liberty and equality so that the ideal that each represents can be served without sacrificing the other?

So far as I know, these questions do not appear in ancient or mediaeval thought, certainly not with the clarity and explicitness with which modern thinkers have posed them. I must also say that, so far as I know, sound answers to these questions cannot be found in modern thought. Quite the contrary! Such answers as can be found there are, upon close examination, unsatisfactory — inadequate and untenable. However, recourse to the wisdom of Aristotelian and Thomistic thought provides us with two crucial insights which hold the key that will solve these modern problems. The first is that neither liberty nor equality is a supreme or sovereign value. Justice is sovereign; the pursuit of both liberty and equality must be regulated by criteria of justice. When they are so regulated, there is no irreconcilable conflict between efforts to maximize liberty on the one hand and efforts to maximize equality on the other, for neither should be maximized beyond a limit appointed by justice. We should not seek more liberty than justice allows, for beyond this limit lies not liberty, but license — actions that injure other individuals or the community as a whole. We should not seek more equality than justice requires, an equality with respect to all the external goods or conditions to which every one has a natural and, therefore, an equal right. Within these limits, both equality and liberty can be maximized without conflict.

Bodyguards of Truth

“In wartime,” Winston Churchill said, “truth is so precious that it should always be attended by a bodyguard of lies” to safeguard it against detection by the enemy. In modern times, philosophical thought also needs a bodyguard to protect it from succumbing to the errors that abound on all sides. Or perhaps I should say that, in the life of the mind, the pursuit of truth is so precarious that it needs safeguards to keep it from falling into error. These safeguards are themselves truths — a relatively small number of insights and distinctions that should underlie all our thinking to protect us from the little errors in the beginning that have such serious consequences in the end.

Let me, on this occasion, briefly state certain insights and distinctions that, in my own philosophizing, have served as the bodyguards of truth. I owe all of them to Aristotle and Aquinas or to the philosophical tradition associated with their names. To mention all the errors from which these insights and distinctions save us would extend this address far into the night. I shall content myself with brief indications of typical modern errors against which they seal the mind.

1. Psychology and theory of knowledge. Before I began carefully to study Aquinas’ Treatise on Man in the Summa, I was exposed to Locke’s Essay Concerning Human Understanding and, I should also add, I taught psychology at a time when the introspective psychology then regnant was first challenged by John B. Watson’s behaviorism. That is why I will never forget the light that swept across my mind when I first came upon the passage I shall now mention. It occurs in Article 2 of Question 85 in the Treatise on Man, where Aquinas replies to the objections of those who say that sensible and intelligible species are that which we perceive and understand.

To make the point quite clear, let me translate these mediaeval terms into the modern vernacular, by referring to both sorts of species as ideas, just as Locke did. Thus translated, the point Aquinas makes, a point totally ignored by all of modern psychology, is that ideas are not that which we apprehend, but that by which we apprehend whatever it is that we do apprehend. Perceptions, imaginations, and memories (ideas in the sensible order) are wholly the means or instrumentalities by which we apprehend sensible objects. Concepts (ideas in the intelligible order) are wholly the means or instrumentalities by which we apprehend intelligible objects.

From this it also follows that we never experience our own ideas; we experience perceived objects but never the perceptions by which we perceive them; we understand intelligible objects but we have no awareness of the concepts by which we understand them, not even when the mind reflects upon its own operations. Ideas are completely self-effacing as the means by which objects are presented to the mind. They are, therefore, totally uninspectible, unexperienceable, unapprehensible.

Please try to imagine the tortured hours I had spent teaching an introspective psychology that pretended to be directly exploring and examining the contents of our minds, and defending it against a behaviorism that regarded the contents of consciousness as mythical inventions. Please try also to imagine the intense discomfort that I suffered in being unable to avoid the consequences that Berkeley drew from Locke, the consequences that Hume drew from Berkeley and Locke, and the monstrous invention of what Professor Veatch has called the “transcendental turn,” to which Kant deemed it necessary to resort in order to get around Hume. By doing so, you may be able to form some impression of the extent to which my mind was relieved as well as enlightened by that one insight I learned from Aquinas; and how radically it was liberated from the philosophical mistakes that followed from Locke’s little error in the beginning. It actually was at the very beginning of his Essay that Locke, explaining his use of the word “idea” to cover whatever is meant by phantasm, notion, or species, said ideas are “whatsoever is the object of the understanding when a man thinks.”

That statement contains another error which has proliferated in a variety of ways, most disastrously in the nominalism of Berkeley and Hume and in much of contemporary positivism and analytic or linguistic philosophy. Just as Locke used the word “idea” to cover without distinction what Aquinas distinguished as sensible and intelligible species, so he used the word “understanding,” as others have used the word “mind,” to cover the quite different cognitive powers of the sensitive and the intellectual faculties, without clearly distinguishing the one from the other. (This is one error that Kant did not make.)

From these twin errors flow the modern failures to deal with universals and to solve the problems appropriate to a philosophy of language. Even worse, from them flow the insoluble paradoxes and puzzlements that result from regarding our subjective ideas — the ideas that each has in his own mind — as not only objects that we directly apprehend, but also as representations of the really existing things that we cannot directly apprehend, but about which, nevertheless, we seek to acquire knowledge. Those paradoxes and puzzlements can be avoided or resolved in terms of the Thomistic insight that ideas are neither objects apprehended nor representations of things unapprehended, and in terms of the Thomistic distinction between our apprehension of objects, which is neither true nor false, and our knowledge of things by judgments which are either true or false.

I would add that the modern dichotomy of things existing outside the mind (often mistakenly referred to as having objective rather than real existence) in contradistinction to ideas existing inside the mind (regarded as having subjective existence) should be replaced by the Thomistic trichotomy of the real existence of things, the intentional existence of objects, and the subjective existence of ideas.

2. Moral and political philosophy. In turning now to the safeguards of truth in the sphere of moral and political philosophy, I pass over consequential modern errors in metaphysics, comparable to those I have just mentioned in psychology and the theory of knowledge. Before Locke, the modern period has only three thinkers — Descartes, Spinoza, and Leibniz — who address themselves to questions that belong to metaphysics as the science of being, the modes of being, and the properties of being. The diverse mistakes they make with regard to substances and causes, matter and form, body and mind, do not spring from a single little error like that about ideas. I will, therefore, not attempt to analyze in detail what I think is the misdirection of their thought. After Locke, and especially after Hume and Kant, there are remarkably few modern thinkers who deal with the problems of metaphysics as those are set forth in Aristotle’s Metaphysics and Aquinas’ De Ente et Essentia. The subject-matter that is examined and illuminated in those two treatises has been terra incognita for almost three hundred years. All the while, the word “metaphysics” has been used by positivists as a term of reproach to name post-Kantian speculations which cannot be defended against their criticisms, but which are also not metaphysical in the proper sense of that term.

In political philosophy, two controlling insights serve as guardians of truth. One is the insight that enables us to understand that the state is both natural and conventional (natural in its final cause, conventional in its efficient cause). With this understood, we are saved from the necessity of imagining the origin of the state and government by recourse to the myth about men living in a state of nature. That modern myth is still in vogue, as two widely discussed recent books in political philosophy make painfully evident. Many serious errors in both books — the one by Professor Rawls and the one by Professor Nozick — might have been avoided had an understanding of human nature and the naturalness of the state not been displaced by fictions concerning the state of nature and the social contract.

The other controlling insight in political philosophy lies in an understanding of two distinct senses of the common good: on the one hand, the public good that is common because it is participated in by the members of an organized community; on the other hand, the private good that is common because it is the same in all men. The first of these common goods, the bonum commune communitatis, is the end aimed at directly by just governments; the second, the bonum commune humanis, is the temporal happiness or good human life which is man’s ultimate end on earth, and toward the achievement of which the public good and private virtue are indispensable means.

This insight saves us from the central deficiency in Mill’s utilitarianism — his inability to relate the general happiness, or the happiness of others, to the individual’s own happiness as the ultimate end of his striving. We act for our own happiness directly, but for the happiness of others we act indirectly when we act for the public good of the community, which is an indispensable condition of their being able to make good lives for themselves.

What I have just said would not be understood by a single modern thinker who has anything to say about happiness in his moral philosophy. All of them make two mistakes that an understanding of Aristotle’s Ethics would have helped them to avoid. One is their failure to distinguish between happiness as a terminal end (an end that can be reached and enjoyed at a given moment in time — or in eternity), and happiness as a normative end (an end that, being the temporal whole of an entire life well lived, can never be experienced or enjoyed at any moment in the process). Inseparable from that mistake is their misconception of happiness in purely psychological terms as the state of contentment that results from satisfying whatever desires an individual happens to have. Not a single modern philosopher, from Locke, Kant, and J. S. Mill on, conceives happiness in purely ethical terms as the quality of a whole life that results from satisfying, successively and cumulatively, not any desires, but only right desires.

The reason for this is an even deeper underlying failure — the failure to take note of the Aristotelian and Thomistic distinction between natural and elicit desires: desires common to all men because they are rooted in the specific nature and capacities of man, and desires that differ from individual to individual because they are products of individual circumstances, individual differences, and individual experiences. Let me use the terms “natural needs” and “individual wants” to name these two distinct types of human desire. The things we call good because we do in fact want them are only apparent goods; the things we ought to desire because they are in fact good are, in contradistinction, real goods. This is another distinction to be found in Aristotle which moral philosophy in modern times has ignored.

Only when this distinction is understood, can we recognize the self-evident truth of the moral imperative that we ought to desire everything that is really good for us and nothing but that which is really good. Without it, little sense can be made of Augustine’s magnificent maxim: Happy is the man who has everything he desires, provided he desire nothing amiss. Without it, and without the insight that natural rights derive from natural needs or right desires, the doctrine of natural rights ceases to give substance to the theory of general, as distinct from special, justice, which is still another distinction currently ignored.

I cannot go on without adding that my delight in Augustine’s succinct summary of the happy life is intensified by noting its correlation with Aristotle’s definition of happiness as the quality of a life lived in accordance with virtue; for moral virtue is simply the habit of desiring nothing amiss.

I have left for the last one point that would have saved moral philosophy in modern times, especially in the last hundred years, from its unsolved perplexities with regard to the grounds upon which normative judgments can claim to be true. If the only type of truth that is recognized is the truth that lies in the agreement between a judgment and the reality it describes, then normative judgments — assertions of what ought to be, not assertions of what is — cannot be either true or false. The only way to avoid the conclusion that ethics must be non-cognitive is to recognize that the truth in normative judgments is quite distinct from the truth in descriptive judgments. Aristotle and Aquinas are the only philosophers in the whole tradition of Western thought who accurately perceived the difference between what they called speculative and practical truth, which I have just called descriptive and normative truth.

The distinction is made in a single sentence in Book VI of the Nicomachean Ethics. Practical truth, Aristotle says there, is the truth of a judgment that conforms to right desire, whereas speculative truth is the truth of a judgment that agrees with the way things really are. The normative judgment that something ought to be desired because it is really good is a judgment that is true because it conforms to a right desire. In contrast, a normative judgment is false if it asserts that something which a man wants but does not need — an apparent, not a real good — ought to be desired.

The whole body of ethical truths emerges from the distinction between real and apparent goods, the distinction between natural needs and individual wants, and the insight that needs are always right desires whereas wants may be wrong desires or, at best, permissible desires — permissible because innocuous, as they are when what is wanted by an individual does not prevent him or other individuals from attaining what is needed.


Let me mention one other lesson that all later philosophers should have learned from Aristotle. It is a lesson that Aquinas learned well and honored by his observance of its precepts, but one which has not been generally honored by the practice of thinkers in modern times.

“The investigation of truth,” Aristotle tells us, “is in one way hard, in another easy,” for “no one is able to attain the truth adequately, while, on the other hand, we do not collectively fail.” The measure of mankind’s success in the collective pursuit of truth, especially philosophical truth, will depend on the degree to which philosophers follow Aristotle’s recommendation that each generation of thinkers should “call into council the views of [their] predecessors in order that [they] may profit by whatever is sound in their thought and avoid their errors.”

This recommendation certainly was not followed in the systembuilding efforts of Descartes, Spinoza, and Leibniz, each of whom engaged in philosophical thought as if he were the first philosopher on earth. Nor can it be said of other modern thinkers, especially those in our own century, for whom the great philosophical works prior to the 17th century are either closed books misread and misjudged because of the modern prejudice that anything written before the dawn of modern times cannot possibly have much, if any, truth in it. In contrast, the whole of the Summa Theologica is a sustained example of conscientious observance of this recommendation.

Source: The Aquinas Medal Acceptance Speech, Proceedings of the American Catholic Philosophical Association, 1976, pp. 125-133.

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