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From the November, 2000 issue of Touchstone


Clear Philosophy by Eric Scheske

Clear Philosophy

The Unity of Philosophical Experience
by Etienne Gilson
San Francisco: Ignatius Press, 1999
(269 pages; $17.95, paper)

by Eric Scheske

In his story, “The Gifts of the Child Christ,” George MacDonald describes the quietly unhappy marriage of a serious middle-aged man and his frivolous young wife. The man was discouraged by his wife’s simple-minded joys. He wanted her to take an interest in serious topics, like poetry and science, but his efforts to instruct her always failed because he didn’t approach the task properly. Instead of trying to teach her poetry from Milton, the narrator points out, “He ought to have read with her the books she did like, for by them only could he make her think, and from them alone could he lead her to better.”

This is what Etienne Gilson has done in The Unity of Philosophical Experience by using an easier discipline (history) to help explain a more difficult discipline (philosophy1). Through a 900-year jaunt from the Middle Ages to the early twentieth century, Gilson has used historical narrative to illuminate deep philosophical issues and explain with clarity the systems of the last millennium’s most profound philosophers, especially Abelard, William of Ockham, St. Bonaventure, Descartes, Malebranche, Locke, Kant, and Comte. Gilson also provides a fair amount of insight into the philosophies of a host of other thinkers, including Moses Maimonides, Petrarch, Nicholas of Cusa, Montaigne, Leibniz, Spinoza, Berkeley, Hume, Newton, Rousseau, Fichte, Hegel, Feuerbach, and Marx. In short, the book provides a heavy dose of philosophical knowledge for anyone who wants to expand his knowledge in that area.

But that’s not the purpose of the book.

Just as history is a backdrop to Unity’s analysis of the last millennium’s greatest minds, the analysis itself serves as a backdrop to Gilson’s life work. In his other books, Gilson defends Christian philosophy; in Unity, Gilson goes on the offensive, striking deep (and, I think, commonsense and therefore mortal) blows at the fathers of modern thought. And in the process he makes the thoughts of these philosophers clear.

This is somewhat unusual for a philosophical history. Other philosophical histories tend to strive for “objectivity,” with the result that the different philosophers get bogged down in the muddle of relativity. Gilson’s narrative, on the other hand, quietly throws the modern philosophers against the screen of truths perceived by Christian philosophy, thereby revealing the philosophers’ hollowness. Though he only indirectly refers to Christian philosophy, the implication is there: The modern errors are difficult to avoid without resort to Christian philosophy and, ultimately, to divine revelation, which works with human reason to fulfill it.2 Gilson never says this (though he seems to point at it in the last chapter), but by toppling the trees of modern thought, he clears the path for anyone who wants to pursue it.

Degenerate Skepticism

The theme of this book is summed up in the last chapter: “Theology, logic, physics, biology, psychology, sociology, economics, are fully competent to solve their own problems by their own methods; on the other hand . . . as metaphysics aims at transcending all particular knowledge, no particular science is competent either to solve metaphysical problems, or to judge their metaphysical solutions” (p. 249). When a branch of knowledge purports to do this, it degenerates into an “ism.”

Unity describes a series of these “isms,” such as the logicism of Abelard, the theologism of St. Bonaventure, the physicism of Kant, the mathematicism of Descartes, and the sociologism of Comte.

In Chapter III, for instance, Gilson explores the psychologism of William of Ockham. Ockham taught that knowledge is attainable only by intuition—that which our senses directly show us. Ockham’s reliance on intuition was combined with his famous “razor,” which taught that we should never presume the existence of anything else if it is not absolutely necessary to explain a thing or occurrence. So, for example, intuition shows us hand puppets, but the razor tells us we cannot automatically presume the existence of hands, since the puppets could be supported without hands. Most notably, they could be supported by the will of God, which was Ockham’s favorite possibility (he thought references to things beyond the razor detracted from God’s powerful glory).3

The philosophical upshot of this is perhaps best seen with respect to the phenomenon of “cause and effect.” Ockham said you can directly see Item A (say, a cue ball) and you can see Item B (the eight ball). He said you can see the cue ball hit the eight ball, but you cannot thereby assume that the cue ball was the cause of the eight ball rolling into the pocket because, although you can see cause at work, you can’t see cause itself. You can’t pick up and touch “cause”; it is not a directly sensible thing. You only see Item A and Item B repeatedly working with each other to produce the impression of cause and effect, but that is not the same thing as directly sensing the cause, and we are therefore wrong to posit the existence of a cause (cf. pp. 66–67).

This, Gilson says, is sound psychology. Our knowledge is gained from direct sense and, mentally speaking, we really can’t see or feel “cause.” Ockham, however, was engaging in psychologism to say that this psychological fact represented reality. He took a psychological fact and applied it to the functioning of the real world, with the result that he posited an absurd picture of the world and one that, for obvious reasons, led to skepticism.

Skepticism, Gilson repeatedly illustrates, is the ultimate result of all the “isms.” The “isms” of the late Middle Ages (such as the psychologism of Ockham and the theologism of St. Bonaventure) led to conflicting metaphysical systems, which caused widespread skepticism as ultimately displayed in Montaigne. Montaigne’s skepticism, in turn, spurred Descartes to find a different source of truth, which led to his mathematicism, spiritualism, and idealism, which eventually broke down and led to the skepticism of Hume. Hume’s skepticism then awakened Kant, who, like Descartes, sought to revive truth through another round of metaphysical errors (called physicism by Gilson), and it also led to Comte’s efforts to capture metaphysics in his new science of sociology (sociologism). Both of these “isms,” in turn, contributed to the widespread skepticism that is our lot today.

Gilson’s Lucid Prose

Gilson has a remarkable ability to explain the deepest philosophical questions with clarity and precision (he doesn’t purport to answer the questions, but he illuminates them). This is a consistent trait of some of his most well known books, like Reason and Revelation in the Middle Ages, God and Philosophy, and The Spirit of Mediaeval Philosophy.

Unity bears the same trait. I, for instance, have had an amorphous understanding of the philosophical problem of universals for years, but I never appreciated its root until I read Gilson’s simple explanation in Unity: “How is it that in a world where all that is real is a particular and individual thing, the human mind is able to distribute the manifold of reality into classes, in which particular things are contained” (p. 4). In one sentence, one of the biggest issues in philosophical history was illuminated immediately. Then, through his clear account of Scholastics like Abelard, I came to a fuller understanding of universals and the different schools of thought about universals (realism, conceptualism, and nominalism).

This isn’t to say that the book can be read lightly. Far from it. It must be read cautiously and purposefully. The prose is good and clear and therefore understandable, but the topics are nonetheless complex.

Background Knowledge

When reading Unity, it helps if the reader brings some philosophical background to the table. In the first part of the book, which deals with Scholastic philosophy, the reader needs only a cursory understanding of medieval philosophy. In the second part (Descartes and his progeny), the reader needs no background knowledge, because Gilson explores Descartes’s dualism so thoroughly that the book serves as both a primer on and an exegesis of Descartes.

But the third part (which deals with Kant, Comte, and their intellectual descendants) requires a fair amount of background knowledge. This, by the way, might be understandable, given that Unity consists of a series of lectures Gilson delivered at Harvard in 1936. Harvard has always been a paragon of modernism (Yale was organized by men like Cotton Mather in response to Harvard’s modernizing ways), so Gilson’s audience was probably thoroughly acquainted with modern philosophy, with the result that Gilson’s narrative, starting in the late eighteenth century, increasingly presumes a certain amount of knowledge on the part of the reader.

The chapter on Kant, for instance, requires more background knowledge than earlier chapters, and the next chapter on Comte requires even more,4 though the chapters should still be interesting regardless of the reader’s background. But the second-to-last chapter (“The Breakdown of Modern Philosophy”) practically accelerates into a “Who’s Who in Modern Philosophy,” a listing of philosophers and only a sentence or two about their thought. Readers unfamiliar with modern philosophical thought may need to consult other resources to make these references intelligible.

In The Unity of Philosophical Experience, Gilson has largely succeeded in dissecting and explaining difficult material in an enjoyable manner. I thoroughly recommend this book to anyone who values philosophy and wants to know how one of our century’s preeminent historians of philosophy has assessed the major figures of philosophy.


1. By philosophy, I refer to metaphysics (with ontology). The other branches of philosophy (logic, politics, esthetics, and ethics) play limited roles in this work.

2. Christian philosophy is “every philosophy which, although keeping the two orders (of revelation and reason) formally distinct, nevertheless considers the Christian revelation as an indispensable auxiliary to reason.” Etienne Gilson, The Spirit of Mediaeval Philosophy (University of Notre Dame Press, 1991), p. 37.

3. This is my example, not Gilson’s.

4. The Drama of Atheist Humanism (a book by Gilson’s friend, Henri de Lubac) would be an excellent place to start with Comte. It, too, has recently been reprinted by Ignatius Press.

Eric Scheske works as an attorney in Sturgis, Michigan, where he attends Holy Angels Catholic Church. In addition to Touchstone, his articles have appeared in New Oxford Review, Culture Wars, Lay Witness, The Catholic Faith, and Gilbert!

“Clear Philosophy” first appeared in the November 2000 issue of Touchstone. If you enjoyed this article, you'll find more of the same in every issue.

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