Mortimer J. Adler
Mortimer J. Adler; drawing by David Levine

Particular academic disciplines do not institute bodies formally charged with the maintenance of ethical standards, as do such professions as medicine and law whose services have a more immediate practical interest. But they do develop some sort of agreement about the line between respectable and less respectable ways of practicing the discipline in question. (At times there is the unfortunate situation of competing doctrinal schools each trying to draw the line so as to put all who are outside the school on the wrong side of it.) This agreement will not exert itself through an explicit apparatus of courts and condemnations. But it has sanctions at its disposal; exclusion from posts, a unanimously dismissive style of reviewing, the conspiracy of silence.

There are three main offenses against academic respectability and they are found and penalized more often, for obvious reasons, in the humanities. They are the pursuit of money, the propagation of ideology (political or religious), and over-weeningness, in other words, biting off more than any ordinary scholar would regard as possible to chew. Money is best pursued by popularization, the enlargement of the market. The offense here is to conform, against one’s better judgment, to the expectations of the herd, to eliminate the intrinsic difficulty of a subject, to make it congenial and attractive at the possible expense of its proper intellectual values. Sir Arthur Bryant, Gilbert Highet, and the late C.E.M. Joad have been subjected to attack on these lines. In recent years the possibilities in this area have been much enlarged by the industrialization of popular enlightenment with large illustrated volumes for the coffee table, encyclopedic works issued in weekly parts with their munificent “editorships” for men of proved academic distinction, or, at any rate, reputation. But this, as the case of A.J.P. Taylor shows, can be survived. It is, after all, a mode of enrichment that can be indulged in on a part-time basis. It is permissible to pick up some money on the side but not to make it the predominant object of one’s efforts.

The offense of ideological commitment is less disastrous, provided that it is not combined with employment by an ideological institution, a church, or a political party. Philosophy is obviously relevant to religion, history and social science to politics; literary study stands in a slightly more remote relation to both. Philosopher-priests are most respected when they avoid the philosophy of religion, politician-historians when they stick to the study of the reasonably remote past. Over-weeningness, even more than ideology, tends to be associated with the achievement of financial success, even if not with its deliberate pursuit. It must be their status as best-sellers that has exposed Toynbee and Teilhard de Chardin to such aggressive comment. In a way there is something disarming about the explicit pursuit of money. The dun-colored and respectable, secure in the armor of their cloistered virtue, can afford to dismiss straight money-makers with moderately indulgent raised eyebrows. Those who achieve wordly success apparently without having aimed at it evoke a stronger reaction.

Mortimer J. Adler would, I imagine, be regarded by most professional philosophers as at best a denizen of the twilight zone. To start with he has been identified with a definite ideological position; orthodox Catholic Christianity and political conservatism. This was the theme of his association during his time at Chicago between 1930 and 1952 with Robert M. Hutchins. The Great Books program that they devised served the interests of traditional Christian philosophy, more specifically Catholic scholasticism, and involved a rejection of the social and educational ideals of the American version of secular rationalism, which is roughly to say John Dewey. Adler defended philosophical deduction against inductive science, tradition (as incarnated in the Great Books) against progressive innovation, the wisdom of traditional institutions, such as the church, against individual human reason.

But with the passage of time a discernibly commercial aspect, calculated to modify the style of respectable hostility, has come over his activities. There is a Jack Benny situation in which Benny says to a visitor who has admired some article of furniture “would you like it then” and opens a cupboard to reveal a large roll of wrapping paper and a cash register. Adler’s remark, toward the end of The Conditions of Philosophy, “I am going to risk what looks like special pleading. I hope I may be pardoned for referring here to the program of the Institute for Philosophical Research…” has something of the same gently comical quality. The Great Books themselves and the Syntopicon, a large analytical index that Adler has attached to them, have been the subjects of an energetic marketing campaign. I once sent in a coupon from TV Guide in order to get a 64-page free colored brochure about them. I received instead a visit from a man in a station wagon who reminded me of the hero of John Updike’s Rabbit Run. He could not be induced to sell me the Syntopicon unless I bought the Hundred Great Books as well.


In 1952 Adler founded the Institute for Philosophical Research and has since been its director. It is a body of anonymous toilers who sift from the corpus of philosophical literature all references to some of the leading ideas among the 102 given canonical status in the Syntopicon. Its first bulky fruit was a two-volume study The Idea of Freedom (1958, 1961). More recently briefer studies of the ideas of happiness, justice, love, and progress have appeared. Adler labels the work of his Institute “dialectical.” It resembles the preparation of memoranda for the higher executives of a bureaucracy. It seeks “to take stock of the whole accumulation of philosophical opinions on a given subject” with a view to constructing from these materials a rational debate about the issue in question. Adler’s assiduous dialecticians are under-laborers whose task is to make things easier for those capable of creative philosophical thought. With 97 of the Syntopicon’s great ideas still to be dialectically explored the Institute has plenty of work before it.

At various points in The Conditions of Philosophy and The Difference of Man and the Difference It Makes the churning noises of this large industrial undertaking are audible, but Adler does not come before the reader of these books as a philosophical entrepreneur. They are substantial treatises on topics of primary philosophical interest, organized in the ordinary argumentative fashion and not “dialectically,” although some of the bibliographical notes testify to the Institute’s resources in the way of information retrieval. In the first book Adler lays down the conditions that philosophy must satisfy if it is to recover the general respect that is now accorded to science and history but no longer to it. Mistaken views about the proper conduct of the discipline are criticized. Elements of virtue are discerned in styles of philosophizing that are otherwise deficient. The main controversial issue, the English-speaking philosophical environment being what it is, is Adler’s insistence that philosophy cannot be simply a second-order, critical or analytic activity, occupied with the clarification of other, substantive varieties of knowledge. It must be a first-order discipline with a subject matter of its own.

The more recent book surveys a good deal of philosophical and scientific thinking, but its main aim is to bring out the essentials of the dispute between those who see man as a part of nature and those who do not. Adler prefaces his inquiry into the existence of a radical difference of kind between men and other things with a general theory about the nature, of difference. He concludes that reasoning alone cannot effectively settle the dispute. It hinges on the truth or falsity of the prediction that men will be able to construct a machine which can converse with them as they converse with one another. Adler stakes his implied preference for the view that men are radically different from other things on the prediction that this technological feat will not be accomplished.

The first thing to say about these books is that they are plainly the work of an intelligent and well-informed man. They are written with great lucidity. As far as the main argument is concerned, all the author’s cards are laid unequivocally on the table. It is possible to doubt whether Adler’s neutrality in the dispute discussed in the second book about the difference between men and other things is as complete as his manner of handling it there seems to suggest. But stating the problem as he does as one of determining just what is in dispute about the uniqueness of man and just what would be needed to resolve it, he is altogether within his rights in adopting the rather unearthly detached manner that he does. He is particularly conscientious about making the logic of his reasoning explicit. He nowhere relies on allusion, rhetoric, or the probable preconceptions of the reader. Considered simply as expositions of rather elaborate trains of abstract reasoning, these books have much to commend them. The style is plain and effective rather than elegant or memorable. There are occasional lapses into malapropism: “denumerable” for “innumerable,” “hypothecate” for “hypothesize,” “protagonist” for “supporter.”

Adler has done a good deal of homework, particularly in the second book where it is more needed, in both philosophy and science. As well as arguments and theories in the philosophy of mind, ancient and modern, he has carefully assembled material from evolutionary biology, paleontology, ethology, experimental psychology, neurology, and cybernetics. I am not qualified to pronounce on the thoroughness and representativeness of his selection of scientific material, but in philosophy he covers the available contributions adequately, with one serious exception. This is that he says nothing about the Wittgensteinian philosophy of mind (as expounded by Wittgenstein himself, Malcolm, Shoemaker, Anscombe, and Melden). Yet in no philosophical school is the attribution of man’s uniqueness to the fact that he alone is a language-user more emphatic. It may be that the Wittgensteinians’ denial of the relevance of science explains his neglect of their ideas. He does tend to skirt around technical complexities (such as the tangled issue of intentionality) which it would be hard to treat with the degree of lucidity he has imposed on himself. But this does not obviously impair the force of what he has to say. So in whatever relation these two books stand to the vigorous corporate enterprise that markets the Great Books and the Great Ideas, they deserve consideration in their own right as contributions to philosophical debate.


The Conditions of Philosophy begins by laying down the requirements that philosophy must satisfy if it is to regain a status alongside, or even a little above, that of science and history. The more controversial and interesting of these are that philosophy should aim at knowledge in the sense of well-founded belief (doxa) and not at demonstrative certainty (episteme), that it should be carried on as a public, cooperative enterprise, and that it should be substantive, that is, it should be not merely critical, but should have a first-order subject matter of its own. As Adler sees it, existentialism deals with first order questions but in an idiosyncratic, more or less poetic way, while analytic philosophy, although a rational, public undertaking, refuses to address itself to substantive problems of the first order; analytic philosophy studies not the world but our knowledge of or discourse about it.

The requirement of first-order subject matter for philosophy in effect asserts the possibility of metaphysics, a position which was polemically denied by the positivists of the 1930s. But in fact Adler himself rejects the kind of metaphysics the positivists wished to eliminate: the establishment by purely demonstrative means of a general theory of the world. His position is determined by the requirement that philosophy should be well-founded belief, not demonstrative certainty. He agrees with the analytic philosophers that substantive knowledge of the world must be corrigible and rest on experience. But where they say philosophy can be demonstrative because it is conceptual not empirical, he maintains that its fundamental part, because substantive, must be empirical. His requirements of substantiveness and corrigibility go together.

One is tempted to ask why philosophy must have a first-order subject matter. What is so disreputable about knowledge about knowledge as compared with knowledge about matter or life or the human past? There is a hint in Adler’s demand for substantiveness of the kind of inverted proletarian snobbery which denies that anything but manual work is really work, or that anything but manufacture is really productive. Do they not also serve who only sit and analyze? But there are other, less rhetorical objections.

To start with he tells us surprisingly little about the detailed content of philosophy’s proprietary subject matter. There is a list of problems on page 43, and thereafter, whenever it becomes appropriate to be at all specific about the requirement of substantiveness, he refers back to this brief and unelucidated catalogue. Substantive questions are of two kinds: speculative questions about what is and happens in the world and practical questions about what men should do and seek. Among the list of speculative questions, which is shorter than it looks because of thinly disguised repetitions, are “the nature of being and existence,” “change itself and the types of change,” “causation and the types of causes,” “necessity and contingency,” “the material and the immaterial,” “freedom and indeterminacy.” But Adler does not seem aware that every problem in the list can easily be given a second-order, conceptual, interpretation: How should the concepts of existence, change, cause, etc. be analyzed? What is more, the most obvious method for dealing with the problems in Adler’s list is conceptual. What clear sense can be given to the problem of the “modes of being” other than by raising the question of what the logically distinct varieties of significant assertion of existence are? In a way, of course, there is an empirical element to this inquiry. We must start from our common empirical awareness of the kinds of claims to knowledge of existence that people are actually disposed to make. But this, though empirical knowledge, is still second-order. It does not relate to the contents of the world in general but to claims that are made for knowledge about the world.

Adler rests his case for substantive philosophical knowledge on a distinction between what he calls special experience, which is acquired by deliberate and systematic, or, as he puts it, investigative, study of the world, the evidential basis of science and history, and common experience, the fruit of non-investigative observation. Now there is, no doubt, a difference between observational knowledge that is acquired by deliberate investigation and knowledge that is just passively and casually picked up. But what non-investigative observation yields is common knowledge or common sense rather than philosophy. What is more, having or lacking an investigative origin distinguishes the way in which knowledge is acquired, but not necessarily the kinds of things known. While elusive things like molecules have to be found by investigation, much of science is concerned to establish methodically things that we know already by common observation of the non-investigative sort.

To the extent that common experience does give rise to a proprietary sort of knowledge, then, it is common sense knowledge, not substantive, metaphysical philosophy. Adler assigns two functions to philosophy in relation to common sense. The first is the second-order business of defending it against science and against mistaken philosophical skepticism, a program indistinguishable from that of G.E. Moore, a founding father of analytic philosophy. Secondly, philosophy should develop theoretical constructions to explain common phenomena. What these are he does not specify, but God, the soul, and universals would seem reasonable candidates for the task in question. This is to conceive metaphysics as a science based on unscientific evidence. Adler’s rather vague account of the relation between substantive philosophy and common experience is in fact compatible with the position of the analytic philosopher, for the latter does not suppose his conceptual investigations to take place in thin air. Their field is not that of bare conceptual possibilities but the comparatively empirical one of the conceptual activities that men actually engage in.

Adler is even less specific about the other, practical branch of substantive philosophy. It is, he says, the most publicly useful part of the subject. Science can discover means to our ends but it cannot determine the ends themselves. For them we must turn to the maid-of-all-work: common experience. But how it underwrites moral convictions is left wholly unexplained. To support his claim of the ethical incapacity of science he invokes the familiar doctrine that naturalism is a fallacy: the opinion, imposed by G.E. Moore on a generation of moral philosophers, that judgments of value are logically unique and cannot be deduced from statements of fact. But if this is so, then common experience is as powerless as the special experience science rests on to justify our valuations. To regard ethical naturalism as fallacious is to reject any kind of observational verification of judgments of value.

In The Difference of Man and the Difference It Makes the question at issue, whether or not there is a radical difference of kind between men and other things, is not a pure question, to be resolved by common experience alone presumably, but a mixed question, where philosophy has to adjudicate between the competing claims of other bodies of knowledge, in particular between the common-sense presuppositions of our practice of according a unique moral status to human beings, on one hand, and the various sciences which stress the continuity between man, other animals, and even machines, on the other. Toward the end Adler advances a traditional scholastic argument to show that no explanation of man’s power of conceptual thought in wholly material terms is logically possible, but he does not rest his case on it. The materialist thesis of basic continuity between men and other, unquestionably material, things would be established if a machine could be built which could be taught to converse with men in the way that they converse with each other. Until such a machine is constructed the materialist case remains unproved.

The first step of his argument is a theory about the kinds of difference that can obtain between different sorts of things. Things differ in kind rather than degree if there is some defining characteristic of one that the other does not share and if there are no intermediaries between them. But such a difference in kind is only apparent if the discontinuity that shows it is merely contingent, if there could be intermediaries although there are in fact none. Real differences of kind may be superficial rather than radical if they can be explained by reference to differences of degree in the explanatory factor. Thus to show that man is unique in the world in a philosophically significant way it must be shown that he differs in kind radically from all other things. If his difference from them could be explained by the greater proportionate size of his brain then he would differ in kind only superficially. The bulk of the ensuing discussions turns on this point. The logically prior question of whether man’s difference of kind is real rather than apparent is hardly considered at all.

But as Adler has defined the notion it is not clear that there is more than an apparent difference of kind between men and other things. As a matter of contingent fact there is a marked discontinuity between men, with their propositional language, construction of tools, and reliance on tradition, and the higher animals who merely signal to one another, improvise tools, and inherit instinctive patterns of behavior. But intermediate cases are conceivable. Dolphins or a lost tribe of Neanderthal men might prove to have the linguistic, technical, and social capacities of moderately bright four-year-old children and imagination could be mobilized to fill the gaps on either side of them in the scale of achievement.

Adler illustrates his account of the concept of difference with mathematical examples. Whole numbers differ in kind, there are no intermediates between 6 and 7, but there are intermediates between any pair of proper fractions: 1/2 comes between 2/5 and 3/5, 9/20 between 2/5 and 1/2 and so on. Adler betrays a naïve realism about concepts in his reliance on this model. It is a form of the Platonic view that ideas are prior to their exemplifications in the natural order. This is far from obvious to those who follow Hobbes, Locke, and Hume in taking our apparatus of concepts to be a human contrivance. For them our concepts are, as Locke put it, rooted in the similitudes of things, but they do not correspond to an antecedently fixed repertoire of natural kinds. Concepts of entities, like numbers, that are themselves conceptual cannot be taken as a guide to the nature of concepts of actual things. The devices with which we classify the objects of experience are influenced in their formation by our interests as well as by the intrinsic nature of the things themselves. Thus a difference in kind in the natural order reflects only a dissimilarity that is definite and interesting enough to lead us to invent a special word to mark it with.

Adler’s presupposition of fixed essences in nature is the consequence of a view of the world as the creation of an intelligent being, working in accordance with a preconceived plan. Now it is just such presuppositions that Adler, in his generally careful neutrality, is anxious to do without. However, the application he makes of this theory can survive its abandonment, in a somewhat chastened form. The idea of a difference of kind can still make perfectly good sense for a non-Platonist; such a difference could be said to rest on the solidity with which the conceptual distinctions we have chosen to introduce are entrenched in our way of thinking about the world. Natural differences in kind can still be important, even if they are all, in Adler’s sense, no more than apparent.

The possession of propositional language is the vital point of difference for him between men and other things. It differs from the more or less linguistic capacities of non-human animals in two ways: in the nature of its elements and in the manner of its employment. Human language consists of “designators,” expressions that have denotation and connotation, and not of “signals” which are only causally related to the immediate stimuli that produce them and to the immediate responses they evoke in their hearers. Secondly, it is not instinctive but employed deliberately and with intention. It testifies to its users’ possession of the power of conceptual thought, which is something quite distinct from a mere recognitional capacity. Conceptual thinkers can transcend their environment; they are not tied to the here-and-now in their mental processes in the way that non-human animals seem to be.

The power of conceptual thought is clearly an important differentia of the human species. The vital question for Adler is whether it is a superficial difference that can be explained by the greater proportionate size of the human brain or a radical difference which has to be explained by the presence in men of an immaterial factor, an Aristotelian rational soul. Adler resurrects a traditional scholastic proof for the thesis that matter cannot think. Concepts, the instruments of thought, he argues, are universal in nature, but all matter is individual. One could as well argue that an immaterial factor is needed to explain how a lock can secure a door since a lock is a wholly material thing, but the function of securing the door is universal, having indefinitely numerous instances or occasions of exercise.

Although he seems persuaded that his scholastic argument for immaterialism is valid, he admits that it is unlikely to carry conviction with those who take conceptual thought to be a power of a suitably complex brain. Instead he offers the materialists a challenge. If matter can think, let them produce a piece of unquestionably material machinery which by conversing with men as they do with each other can give the same sort of evidence as they do of the power of thought. He must, in the light of his view that it can be proved that matter cannot think, be convinced that this cannot be done. But he is prepared to rest his case on the empirical foundation of repeated failure to bring it off. To all appearances the crucial issue is left open, with its decisive resolution projected into the future. But, in fact, if a machine is constructed that from behind a screen persuades a group of investigators that it is a person, the immaterialist will not have to surrender. He can always say that men have discovered the material conditions that have to be satisfied for God to endow a natural object with a rational soul. For he must already believe some such endowment to accompany the conception of a child.

The book ends with a survey of the consequences that would follow a resolution of the dispute one way or the other. As things are, fortified by our general belief in a radical difference of kind between men and other things, we accord a unique moral status to human beings. For most people it is morally permissible to enslave animals or to kill them for food, but human slavery and cannibalism are to be condemned. The invention of conversational machines will bring the boundaries of the moral community up for revision. Adler clearly does not subscribe to the view that the basic condition for membership of the moral community is capacity for suffering. If he did he would not give so little attention to the intrinsic claim of animals to moral consideration, which, even on his principles, is as securely based as that on behalf of human idiots or the hopelessly senile. But whatever happened, his assertion that if a conversational machine were constructed “the moral aspects of human life would be rendered illusory” is extravagant. If a conversational machine were to respond to praise and blame as men do it would be worthwhile reminding it of its duties.

Further consequences would arise for religion. The beliefs that human beings are uniquely personal, are the objects of a special creation, immortal and free, would be undermined. But if materialism turns out to be false and there is an immaterial factor in man, it could be argued that it must have an immaterial cause in God. (Adler thinks this argument is new, but its outlines are in Locke.) At the very end he gives vent to a little partisan ferocity at the expense of the new Christians for whom God is dead. If they think that the divine is not in heaven but in the fact of human personality, they might just as well admit it in heaven. For Adler, God and the soul stand or fall together.

These two books are presentable contributions to current debate about philosophical method and the philosophy of mind, written with admirable clarity and based on fairly wide study. The first book defends a more-or-less Aristotelian, and thus scholastic, idea of first philosophy or metaphysics; the second does not succeed in concealing a commitment to the Aristotelian idea of the rational soul. Both ideas are apt for the defense of orthodox Catholic theology, since the former underwrites the intellectual propriety of natural theology (conceived as theoretical constructions to explain common phenomena) and the latter is a suitable framework for the Christian doctrine of human nature.

But these broadly ideological potentialities are not emphasized. Indeed only in the final footnote of the second book are they recognized by implication, where, considering the possibility of a “positive strengthening of the immaterialist hypothesis,” Adler observes that it “would have earthshaking effects throughout the learned world of the future” and on those laymen who “reflect the naturalistic materialism and atheism of the learned.” There is something about the wording of these comments which suggests that the “positive strengthening” in question would be entirely welcome to their author.

Nothing, at first sight, could be more sweetly reasonable than Adler’s readiness to accept the arbitration of technical progress in the development of mind-like machines as far as the issue of the soul, or “immaterial psychic factor,” is concerned. But on closer inspection this attitude of perfectly disinterested and open-minded neutrality proves to have certain limitations. First, since there is nothing like a conversational machine in existence at the moment, immaterialism has the immediate advantage. Secondly, Adler’s insistence on the final decisiveness of machine construction is misplaced. On the one hand, there can always be dispute about whether a machine has really passed the test. On the other, if this has to be admitted, the immaterialist can fall back on the tactic mentioned earlier of allowing that a new mechanical, rather than biologically reproductive, way has been discovered in which men can get God to endow material bodies with souls. Finally, there is Adler’s commitment to the proof that matter cannot think, developed in considerable, not to say loving, detail in a long footnote. He regards this as valid and does not rely on it only because in present intellectual conditions it will not secure general assent. But if it is valid then either no conversational machine can possibly be constructed or there is a non-biological way in which men can get God to put souls into bodies.

Adler, I am sure, faces the future with complete confidence. We are, to start with, quite a long way technically from any machine that looks like passing his test. If something that looks like passing it does eventually get produced, a little backing-down will be called for, since Adler rejects with some scorn the idea that God would ensoul a machine; but the ranks could be soon reformed. In the meantime the work of the Institute for Philosophical Research goes on. “It is currently engaged,” he writes, “in the study of the whole discussion of language and thought and especially the problem of meaning,” while he himself is working on a book about the problems of moral philosophy. The extreme suavity of Adler’s approach, as compared with the ringing anti-naturalist polemics of twenty or thirty years ago, is a sign of the extent to which “materialism and atheism” have come to prevail among both the learned and the laity. But even in the catacombs preparations are in hand for the better times that are sure to come.

This Issue

November 21, 1968