Mortimer Adler

Mortimer Jerome Adler (December 28, 1902 – June 28, 2001) was an American philosopher, educator, and popular author. As a philosopher he worked within the Aristotelian and Thomistic traditions. He lived for the longest stretches in New York City, Chicago, San Francisco, and San Mateo. He worked for Columbia University, the University of Chicago, Encyclopædia Britannica, and Adler's own Institute for Philosophical Research. Adler was married twice and had four children.

New York City
Adler was born in New York City on December 28, 1902, to Jewish immigrants. He dropped out of school at age 14 to become a copy boy for the New York Sun, with the ultimate aspiration to become a journalist. Adler soon returned to school to take writing classes at night where he discovered the works of men he would come to call heroes: Aristotle, Thomas Aquinas, John Locke, John Stuart Mill and others. He went on to study at Columbia University and contributed to the student literary magazine, The Morningside, (a poem "Choice" in 1922 when Charles A. Wagner was editor-in-chief and Whittaker Chambers an associate editor). Though he failed to pass the required swimming test for a bachelor's degree (a matter that was rectified when Columbia gave him an honorary degree in 1983), he stayed at the university and eventually received an instructorship and finally a doctorate in psychology. While at Columbia University, Adler wrote his first book: Dialectic, published in 1927.

Chicago
In 1930 Robert Hutchins, the newly appointed president of the University of Chicago, whom Adler had befriended some years earlier, arranged for Chicago's law school to hire him as a professor of the philosophy of law; the philosophers at Chicago (who included James H. Tufts, E.A. Burtt, and George H. Mead) had "entertained grave doubts as to Mr. Adler's competence in the field [of philosophy]" and resisted Adler's appointment to the University's Department of Philosophy. Adler was the first "non-lawyer" to join the law school faculty. Adler also taught philosophy to business executives at the Aspen Institute.

Great Books and Beyond
Adler and Hutchins went on to found the Great Books of the Western World program and the Great Books Foundation. Adler founded and served as director of the Institute for Philosophical Research in 1952. He also served on the Board of Editors of Encyclopædia Britannica since its inception in 1949, and succeeded Hutchins as its chairman from 1974. As the director of editorial planning for the fifteenth edition of Britannica from 1965, he was instrumental in the major reorganization of knowledge embodied in that edition. He introduced the Paideia Proposal which resulted in his founding the Paideia Program, a grade-school curriculum centered around guided reading and discussion of difficult works (as judged for each grade). With Max Weismann, he founded The Center for the Study of The Great Ideas.

Popular Appeal
Adler long strove to bring philosophy to the masses, and some of his works (such as How to Read a Book) became popular bestsellers. He was also an advocate of economic democracy and wrote an influential preface to Louis Kelso's The Capitalist Manifesto. Adler was often aided in his thinking and writing by Arthur Rubin, an old friend from his Columbia undergraduate days. In his own words:

"Unlike many of my contemporaries, I never write books for my fellow professors to read. I have no interest in the academic audience at all. I'm interested in Joe Doakes. A general audience can read any book I write—and they do."

Religion and theology
Adler took a long time in his own life to make up his mind about theological issues. He considered himself a pagan when he wrote How to Think About God in 1980. In volume 51 of the Mars Hill Audio Journal (2001), Ken Myers includes his 1980 interview with Adler, conducted after How to Think About God was published. Myers reminisces, "During that interview, I asked him why he had never embraced the Christian faith himself. He explained that while he had been profoundly influenced by a number of Christian thinkers during his life, ... there were moral—not intellectual—obstacles to his conversion. He didn't explain any further."

Myers notes that Adler finally "surrendered to the Hound of Heaven" and "made a confession of faith and was baptized" only a few years after that interview. Offering insight into Adler's conversion, Myers quotes Adler from a subsequent 1990 article in Christianity magazine: "My chief reason for choosing Christianity was because the mysteries were incomprehensible. What's the point of revelation if we could figure it out ourselves? If it were wholly comprehensible, then it would just be another philosophy." In 2000, Adler became a Catholic.

Controversy
Adler was a controversial figure in some circles who saw Adler's Great Books of the Western World project as Eurocentric and racially exclusive. Asked in a 1990 interview why his Great Books of the Western World list did not include any black authors, he said simply, "They didn't write any good books."

Moral Philosophy
Adler referred to Aristotle's Nicomachean Ethics as the "ethics of common sense" and also as "the only moral philosophy that is sound, practical, and undogmatic". In other words, it is (according to Adler) the only ethical doctrine that answers all the questions that moral philosophy "should" and "can" attempt to answer, neither more nor less, and that has answers that are true by the standard of truth that is appropriate and applicable to normative judgments. In contrast, Adler believed that other theories or doctrines try to answer more questions than they can or fewer than they should, and their answers are mixtures of truth and error, particularly the moral philosophy of Immanuel Kant.

Adler believed we are as enlightened by Aristotle’s Ethics today as were those who listened to Aristotle's lectures when they were first delivered because the ethical problems that human beings confront in their lives have not changed over the centuries. Moral virtue and the blessings of good fortune are today, as they have always been in the past, the keys to living well, unaffected by all the technological changes in the environment, as well as those in our social, political, and economic institutions. Adler believed that the moral problems to be solved by the individual are the same in every century, though they appear to us in different guises.

According to Adler, six indispensable conditions must be met in the effort to develop a sound moral philosophy that corrects all the errors made in modern times.

First and foremost is the definition of prescriptive truth, which sharply distinguishes it from the definition of descriptive truth. Descriptive truth consists in the agreement or conformity of the mind with reality. When we think that that which is, is, and that which is not, is not, we think truly. To be true, what we think must conform to the way things are. In sharp contrast, prescriptive truth consists in the conformity of our appetites with right desire. The practical or prescriptive judgments we make are true if they conform to right desire; or, in other words, if they prescribe what we ought to desire. It is clear that prescriptive truth cannot be the same as descriptive truth; and if the only truth that human beings can know is descriptive truth—the truth of propositions concerning what is and is not—then there can be no truth in ethics. Propositions containing the word "ought" cannot conform to reality. As a result, we have the twentieth-century mistake of dismissing all ethical or value judgments as noncognitive. These must be regarded only as wishes or demands we make on others. They are personal opinions and subjective prejudices, not objective knowledge. In short, the very phrase "noncognitive ethics" declares that ethics is not a body of knowledge.

Second, in order to avoid the naturalistic fallacy, we must formulate at least one self-evident prescriptive truth, so that, with it as a premise, we can reason to the truth of other prescriptives. David Hume said that if we had perfect or complete descriptive knowledge of reality, we could not, by reasoning, derive a single valid thought.

Third, the distinction between real and apparent goods must be understood, as well as the fact that only real goods are the objects of right desire. In the realm of appetite or desire, some desires are natural and some are acquired. Those that are natural are the same for all human beings as individual members of the human species. They are as much a part of our natural endowment as our sensitive faculties and our skeletal structure. Other desires we acquire in the course of experience, under the influence of our upbringing or nurturing, or of environmental factors that differ from individual to individual. Individuals differ in their acquired desires, as they do not in their natural desires. This is essentially the difference between "needs" and "wants." What is really good for us is not really good because we desire it, but the very opposite. We desire it because it is really good. By contrast, that which only appears good to us (and may or may not be really good for us) appears good to us simply because we want it at the moment. Its appearing good is the result of our wanting it, and as our wants change, as they do from day to day, so do the things that appear good to us. In light of the definition of prescriptive truth as conformity with right desire, we can see that prescriptions are true only when they enjoin us to want what we need, since every need is for something that is really good for us. If right desire is desiring what we ought to desire, and if we ought to desire only that which is really good for us and nothing else, then we have found the one controlling self-evident principle of all ethical reasoning—the one indispensable categorical imperative. That self-evident principle can be stated as follows: we ought to desire everything that is really good for us.The principle is self-evident because its opposite is unthinkable. It is unthinkable that we ought to desire anything that is really bad for us; and it is equally unthinkable that we ought not to desire everything that is really good for us. The meanings of the crucial words "ought" and "really good" co-implicate each other, as do the words "part" and "whole" when we say that the whole is greater than any of its parts is a self-evident truth. Given this self-evident prescriptive principle, and given the facts of human nature that tell us what we naturally need, we can reason our way to a whole series of prescriptive truths, all categorical.

Fourth, in all practical matters or matters of conduct, the end precedes the means in our thinking about them, while in action we move from means to ends. But we cannot think about our ends until, among them, we have discovered our final or ultimate end—the end that leaves nothing else to be rightly desired. The only word that names such a final or ultimate end is "happiness." No one can ever say why he or she wants happiness because happiness is not an end that is also a means to something beyond itself. This truth cannot be understood without comprehending the distinction between terminal and normative ends. A terminal end, as in travel, is one that a person can reach at some moment and come to rest in. Terminal ends, such as psychological contentment, can be reached and then rested in on some days, but not others. Happiness, not conceived as psychologically experienced contentment, but rather as a whole life well lived, is not a terminal end because it is never attained at any time in the course of one's whole life. If all ends were terminal ends, there could not be any one of them that is the final or ultimate end in the course of living from moment to moment. Only a normative end can be final and ultimate. Happiness functions as the end that ought to control all the right choices we make in the course of living. Though we never have happiness ethically understood at any moment of our lives, we are always on the way to happiness if we freely make the choices that we ought to make in order to achieve our ultimate normative end of having lived well. But we suffer many accidents in the course of our lives, things beyond our control—outrageous misfortunes or the blessings of good fortunes. Moral virtue alone—or the habits of choosing as we ought—is a necessary, but not sufficient condition of living well. The other necessary, but also not sufficient condition is good fortune.

The fifth condition is that there is not a plurality of moral virtues (which are named in so many ethical treatises), but only one integral moral virtue. There may be a plurality of aspects to moral virtue, but moral virtue is like a cube with many faces. The unity of moral virtue is understood when it is realized that the many faces it has may be analytically but not existentially distinct. In other words, considering the four so-called cardinal virtues—temperance, courage, justice, and prudence—the unity of virtue declares that no one can have any one of these four without also having the other three. Since justice names an aspect of virtue that is other regarding, while temperance and courage name aspects of virtue that are self-regarding, and both the self- and other regarding aspects of virtue involve prudence in the making of moral choices, no one can be selfish in his right desires without also being altruistic, and conversely. This explains why a morally virtuous person ought to be just even though his or her being just may appear only to serve the good of others. According to the unity of virtue, the individual cannot have the self-regarding aspects of virtue—temperance and courage—without also having the other regarding aspect of virtue, which is justice.

The sixth and final condition in Adler's teleological ethics is acknowledging the primacy of the good and deriving the right therefrom. Those who assert the primacy of the right make the mistake of thinking that they can know what is right, what is morally obligatory in our treatment of others, without first knowing what is really good for ourselves in the course of trying to live a morally good life. Only when we know what is really good for ourselves can we know what are our duties or moral obligations toward others. The primacy of the good with respect to the right corrects the mistake of thinking that we are acting morally if we do nothing that injures others. Our first moral obligation is to ourselves—to seek all the things that are really good for us, the things all of us need, and only those apparent goods that are innocuous rather than noxious.

The Intellect
Adler was a self-proclaimed “moderate dualist”, and viewed the positions of psychophysical dualism and materialistic monism to be opposite sides of two extremes. Regarding dualism, he dismissed the extreme form of dualism that stemmed from such philosophers as Plato (body and soul) and Descartes (mind and matter):

"Strictly speaking, a human being (as defined by the dualistic theory) is not what common sense supposes that person to be: one indivisible thing. That person is actually divided into two individual things, as different and distinct as the rower and the rowboat in which he sits. If this dualistic theory were true, it would confront us with the most embarrassing, insoluble difficulties should we try to explain how these two utterly different substances could interact with one another, as they appear to do in human behavior. Brain injuries or defects produce mental disabilities or disorders. We also have the reports from neurological surgery that tell of electrical stimulation of the brain producing conscious experiences. How can this be so if mind and brain are as separate as the rower and the rowboat, a separation so complete that it permits the rowboat to be sunk while the rower swims away unharmed?"

Adler also disagreed with the theory of extreme monism. He believed that while mind and brain may be existentially inseparable, and so regarded as one and the same thing, the mental and the physical may still be analytically distinct aspects of it. He put this theory to the test in the following manner:

"Let a surgeon open up an individual's brain for inspection while the patient remains conscious. Let the surgeon dictate to a secretary his detailed observation of the visible area of the brain under scrutiny, and let that area of the brain be its center for vision. Let the patient dictate to another secretary a detailed description of the visible walls of the room in which the surgery is occurring. The language used by the surgeon and the language used by the patient will be irreducibly different: the one will contain words referring to physical phenomena occurring in the brain; the other, words referring to conscious experiences of the room. The extreme monism that asserts not only the existential unity of brain and mind, but also that there is no analytical distinction between them, thus becomes untenable."

Adler was also a harsh critic of the Mind-Brain Identity Theory:

"One extremist theory about mind and brain asserts their identity. Used literally, the word "identity" must here mean that there is no distinction whatsoever between mind and brain. That, in turn, means that the two words -- "mind" and "brain" -- are strict synonyms. If that is the case, we cannot meaningfully ask about the relation of psychology to neurology because psychology is identical with neurology."

After eliminating the extremes, Adler subscribed to a more moderate form of dualism. He believed that that the brain is only a necessary, but not a sufficient, condition for conceptual thought; that an immaterial intellect is also requisite as a condition; and that the difference between human and animal behavior is a radical difference in kind. His reason for this is that their cognitive sensory powers do not and cannot apprehend universals. Their cognitive reach does not go beyond particulars. Hence, we would not be able to apprehend universals if we did not have another and quite distinct cognitive power—the power of intellect. Our concepts are universal in their signification of objects that are kinds or classes of things rather than individuals that are particular instances of these classes or kinds. Since they have universality, they cannot exist physically or be embodied in matter. But concepts do exist in our minds. They are there as acts of our intellectual power. Hence that power must be an immaterial power, not one embodied in a material organ such as the brain.

Adler argued that if such an immaterial power did not exist in human beings, our use of common nouns would not be possible. Particular instances are designated by proper names or definite descriptions. When we use the word "dog," we are referring to any dog, regardless of breed, size, shape, or color. To refer to a particular instance, we would use a canine name, such as "Fido," or a definite description, such as "that white poodle over there lying in front of the fire." Our concepts of dog and poodle not only enable us to think about two classes of animals, they also enable us to understand what it is like to be a dog or a poodle.

According to Adler, The action of the brain, therefore, cannot be the sufficient condition of conceptual thought, though it may still be a necessary condition thereof, insofar as the exercise of our power of conceptual thought depends on the exercise of our powers of perception, memory, and imagination, which are corporeal powers embodied in our sense-organs and brain.

Only if the brain is not the sufficient condition for intellectual activity and conceptual thought (only if the intellect that is part of the human mind and is not found in other animals is the immaterial factor that must be added to the brain in order to provide conditions both necessary and sufficient) are we justified in concluding that the manifest difference in kind between human and animal minds, and between human and animal behavior, is radical, not superficial. It cannot be explained away by any difference in the physical constitution of human beings and other animals that is a difference in degree.

Adler defended this position against many challenges to dualistic theories. For example, David Hume believed that man is equipped with sensitive faculties only, and has no intellect. As a nominalist, Hume then faced the problem of how to explain the meaning of the general words in our everyday language; for example, the common nouns that signify classes or kinds. Hume attempted to solve this problem by arguing that when we use words that appear to have general significance, we are applying them to a number of perceived individuals indifferently; that is, without any difference in the meaning of the word thus applied.

Adler found this explanation to be a complete contradiction. To say that we can apply words to a number of individuals indifferently amounts to saying that there is a certain sameness in the individual thing that the speaker or writer recognizes. Adler argued that if human beings enjoy the powers of conceptual, as opposed to perceptual thought, there would be no difficulty in explaining how words signify universals or generalities. They would derive their significance from concepts that give us our understanding of classes or kinds.

As for the challenge that man's understanding is derived only from sense, and to the denial of “abstract” or “general ideas, Adler cites the following quote:

""Let any man try to conceive of a triangle in general, which is neither Isosceles, Saclenum, nor has any particular length or proportion of sides; and he will soon perceive the absurdity of all the scholastic notions with regard to abstraction and general ideas.""

Adler responded to this challenge in his book "Ten Philosophical Mistakes":

God
In his 1981 book “How to Think About God”, Adler attempts to demonstrate God as the exnihilator of the cosmos. The steps taken to demonstrate this are as follows:

1. The existence of an effect requiring the concurrent existence and action of an efficient cause implies the existence and action of that cause

2. The cosmos as a whole exists

3. The existence of the cosmos as a whole is radically contingent (meaning that it needs an efficient cause of its continuing existence to preserve it in being, and prevent it from being annihilated, or reduced to nothing)

4. If the cosmos needs an efficient cause of its continuing existence, then that cause must be a supernatural being, supernatural in its action, and one the existence of which is uncaused, in other words, the Supreme Being, or God

Two of the four premises, the first and the last, appear to be true with certitude. The second is true beyond a reasonable doubt. If the one remaining premise, the third, is also true beyond a reasonable doubt, then we can conclude beyond a reasonable doubt that God exists and acts to sustain the cosmos in existence.

The reason we can conceive the cosmos as being radically rather than superficially contingent is due to the fact that the cosmos which now exists is only one of many possible universes that might have in fact existed in the past, and might still exist in the future. This is not to say that any cosmos other than this one ever did exist in the past, or ever will exist in the future. It is not necessary to go that far in order to say that other universes might have existed in the past and might exist in the future. If other universes are possible, than this one also is merely possible, not necessary.

In other words, the universe as we know it today is not the only universe that can ever exist in time. How do we know that the present cosmos is only a possible universe (one of many possibilities that might exist), and not a necessary universe (the only one that can ever exist)? We can infer it from the fact that the arrangement and disarray, the order and disorder, of the present cosmos might have been otherwise. That it might have been different from what it is. There is no compelling reason to think that the natural laws which govern the present cosmos are the only possible natural laws. The cosmos as we know it manifests chance and random happenings, as well as lawful behavior. Even the electrons and protons, which are thought to be imperishable once they exist as the building blocks of the present cosmos, might not be the building blocks for a different cosmos.

The next step in the argument is the crucial one. It consists in saying that whatever might have been otherwise in shape or structure is something that also might not exist at all. That which cannot be otherwise also cannot not exist; and conversely, what necessarily exists can not be otherwise than it is. Therefore, a cosmos which can be otherwise is one that also cannot be; and conversely, a cosmos that is capable of not existing at all is one that can be otherwise than it now is.

Applying this insight to the fact that the existing cosmos is merely one of a plurality of possible universes, we come to the conclusion that the cosmos, radically contingent in existence, would not exist at all were its existence not caused. A merely possible cosmos cannot be an uncaused cosmos. A cosmos that is radically contingent in existence, and needs a cause of that existence, needs a supernatural cause, one that exists and acts to exnihilate this merely possible cosmos, thus preventing the realization of what is always possible for merely a possible cosmos, namely, its absolute non-existence or reduction to nothingness.

Adler finishes by pointing out that the conclusion reached conforms to Ockham's rule (the rule which states that we are justified in positing or asserting the real existence of unobserved or unobservable entities if-and only-if their real existence is indispensable for the explanation of observable phenomena) because we have found it necessary to posit the existence of God, the Supreme Being, in order to explain what needs to be explained-the actual existence here and now of a merely possible cosmos. The argument also appeals to the principle of sufficient reason.

Adler stressed that even with this conclusion, God's existence cannot be proven or demonstrated, but only established as true beyond a reasonable doubt. However, in a recent re-review of the argument, John Cramer concluded that recent developments in cosmology appear to converge with and support Adler's argument, and that in light of such theories as the multiverse, the argument is no worse for the wear and may, indeed, now be judged somewhat more probable than it was originally.

Religion in Modern Times
Adler believed that, if theology and religion are living things, there is nothing intrinsically wrong about efforts to modernize them. They must be open to change and growth like everything else. Further, there is no reason to be surprised when discussions such as those about the "death of God" -- a concept drawn from Nietzsche -- stir popular excitement as they did in the recent past, and could do so again today. According to Adler, of all the great ideas, the idea of God has always been and continues to be the one that evokes the greatest concern among the widest group of men and women. However, Adler was opposed to the idea of converting atheism into a new form of religion or theology, and cited many “new theologians” such as Clarence Hamilton, Paul Van Buren, Thomas Altizer and Gabriel Vahanian, who promoted this error:

"Have any great intellectual events been ushered in by the new and "radical" theologians? Any new truths in theology? None. Any new insights into the nature of religion? None. Any new advances for the reform of religion? None. The authors who gave currency to the notions of the new "radical theology" supported their assertions with nothing more substantial than the kind of proof that would satisfy the bellman in Lewis Carroll's Hunting of the Snark who cried: "What I tell you three times is true!" There was, however, a close accord between the ambiguous language they used and their purpose. Their purpose was to transform atheism into a new theology -- "the religionless Christianity," "atheistic religion," "secularized Christianity" -- to preserve some of Christianity's religious teaching while secularizing and combining it with atheism. So the question emerges again. What is new about the new theology? Again the answer is nothing. Atheism is not new, nor is irreligion, nor is secularism. These are very old even when they sounded in the work of the eminent modern predecessors of the new theologians."

Adler saw such movements as obvious and disingenuous attempts to convert atheism and secularism into new forms of religion, rather than calling them by their right names:

"For my part, I respect the honest clear-minded atheist who denies that God exists and tries to offer thought out reasons for the denial. I respect the honest, critically minded agnostic who denies we can ever know whether God exists or not, and treats religious belief as a pure act of faith, incapable of being supported or challenged by rational analysis or empirical knowledge of the world. I respect the person who, in his horror of the superstitions and persecutions that have attended the practices of religious institutions, rejects the whole of religion as something from which man should emancipate himself. But I cannot respect those who corrupt the integrity of words in the very act of addressing matters of central importance in theology and religion. I cannot respect those who instead of calling atheism by its right name, contrive a peculiar set of excuses for atheism (as in the "death of God movement") and then -- in spite of laws against false labeling -- call the result a new theology."

With regard to the apparent increase of secularism or irreligion in our Western society, Adler responded:

"I suggest that the men and women who have given up religion because of the impact on their minds of modern science and philosophy were never truly religious in the first place, but only superstitious. The prevalence and predominance of science in our culture has cured a great many of the superstitious beliefs that constituted their false religiosity. The increase of secularism and irreligion in our society does not reflect a decrease in the number of persons who are truly religious, but a decrease in the number of those who are falsely religious; that is, merely superstitious. There is no question but that science is the cure for superstition, and, if given half the chance with education, it will reduce the amount that exists. The truths of religion must be compatible with the truths of science and the truths of philosophy. As scientific knowledge advances, and as philosophical analysis improves, religion is progressively purified of the superstitions that accidentally attach themselves to it as parasites. That being so, it is easier in fact to be more truly religious today than ever before, precisely because of the advances that have been made in science and philosophy. That is to say, it is easier for those who will make the effort to think clearly in and about religion, not for those whose addiction to religion is nothing more than a slavish adherence to inherited superstition. Throughout the whole of the past, only a small number of men were ever truly religious. The vast majority who gave their epochs and their societies the appearance of being religious were primarily and essentially superstitious.”'''"

Books by Adler

 * Dialectic (1927)
 * The Nature of Judicial Proof: An Inquiry into the Logical, Legal, and Empirical Aspects of the Law of Evidence (1931, with Jerome Michael)
 * Diagrammatics (1932, with Maude Phelps Hutchins)
 * Crime, Law and Social Science (1933, with Jerome Michael)
 * Art and Prudence: A Study in Practical Philosophy (1937)
 * What Man Has Made of Man: A Study of the Consequences of Platonism and Positivism in Psychology (1937)
 * St. Thomas and the Gentiles (1938)
 * The Philosophy and Science of Man: A Collection of Texts as a Foundation for Ethics and Politics (1940)
 * How to Read a Book: The Art of Getting a Liberal Education (1940), 1966 edition subtitled A Guide to Reading the Great Books, 1972 revised edition with Charles Van Doren, The Classic Guide to Intelligent Reading: ISBN 0-671-21209-5
 * A Dialectic of Morals: Towards the Foundations of Political Philosophy (1941)
 * How to Think About War and Peace (1944)
 * The Revolution in Education (1944, with Milton Mayer)
 * The Capitalist Manifesto (1958, with Louis O. Kelso) ISBN 0-8371-8210-7
 * The Idea of Freedom: A Dialectical Examination of the Conceptions of Freedom (1958)
 * The New Capitalists: A Proposal to Free Economic Growth from the Slavery of Savings (1961, with Louis O. Kelso)
 * The Idea of Freedom: A Dialectical Examination of the Controversies about Freedom (1961)
 * Great Ideas from the Great Books (1961)
 * The Conditions of Philosophy: Its Checkered Past, Its Present Disorder, and Its Future Promise (1965)
 * The Difference of Man and the Difference It Makes (1967)
 * The Time of Our Lives: The Ethics of Common Sense (1970)
 * The Common Sense of Politics (1971)
 * The American Testament (1975, with William Gorman)
 * Some Questions About Language: A Theory of Human Discourse and Its Objects (1976)
 * Philosopher at Large: An Intellectual Autobiography (1977)
 * Reforming Education: The Schooling of a People and Their Education Beyond Schooling (1977, edited by Geraldine Van Doren)
 * Aristotle for Everybody: Difficult Thought Made Easy (1978) ISBN 0-684-83823-0
 * How to Think About God: A Guide for the 20th-Century Pagan (1980) ISBN 0-02-016022-4
 * Six Great Ideas: Truth-Goodness-Beauty-Liberty-Equality-Justice (1981) ISBN 0-02-072020-3
 * The Angels and Us (1982)
 * The Paideia Proposal: An Educational Manifesto (1982)
 * How to Speak / How to Listen (1983) ISBN 0-02-500570-7
 * Paideia Problems and Possibilities: A Consideration of Questions Raised by The Paideia Proposal (1983)
 * A Vision of the Future: Twelve Ideas for a Better Life and a Better Society (1984) ISBN 0-02-500280-5
 * The Paideia Program: An Educational Syllabus (1984, with Members of the Paideia Group)
 * Ten Philosophical Mistakes (1985) ISBN 0-02-500330-5
 * A Guidebook to Learning: For a Lifelong Pursuit of Wisdom (1986)
 * We Hold These Truths: Understanding the Ideas and Ideals of the Constitution (1987)
 * Reforming Education: The Opening of the American Mind (1988, edited by Geraldine Van Doren)
 * Intellect: Mind Over Matter (1990)
 * Truth in Religion: The Plurality of Religions and the Unity of Truth (1990) ISBN 0-02-064140-0
 * Haves Without Have-Nots: Essays for the 21st Century on Democracy and Socialism (1991) ISBN 0-02-500561-8
 * Desires, Right & Wrong: The Ethics of Enough (1991)
 * A Second Look in the Rearview Mirror: Further Autobiographical Reflections of a Philosopher At Large (1992)
 * The Great Ideas: A Lexicon of Western Thought (1992)
 * Natural Theology, Chance, and God (The Great Ideas Today, 1992)
 * The Four Dimensions of Philosophy: Metaphysical-Moral-Objective-Categorical (1993)
 * Art, the Arts, and the Great Ideas (1994)
 * Adler's Philosophical Dictionary: 125 Key Terms for the Philosopher's Lexicon (1995)

Collections Edited by Adler

 * Scholasticism and Politics (1940)
 * Great Books of the Western World (1952, 52 volumes), 2nd edition 1990, 60 volumes
 * A Syntopicon: An Index to The Great Ideas (1952, 2 volumes), 2nd edition 1990
 * The Great Ideas Today (1961-1977, 17 volumes), with Robert Hutchins, 1978-1999, 20 volumes
 * ''The Negro in American History (1969, 3 volumes), with Charles Van Doren
 * Gateway to the Great Books (1963, 10 volumes), with Robert Hutchins
 * The Annals of America (1968, 21 volumes)
 * Propædia: Outline of Knowledge and Guide to The New Encyclopædia Britannica 15th Edition (1974, 30 volumes)
 * Great Treasury of Western Thought (1977, with Charles Van Doren)