Spinoza's psychology is dialectical. But it is no indictment of his psychology to point out that it is. It is true, his formal definition of sorrow, for instance, fails supremely to touch the strings of a sympathetic heart. But the philosophical psychologist is not a novelist. The recent claim that "literary psychology" is the only valid psychology, is as well founded as the claim would be that only a "literary physics" is valid. Mathematical physics gives us no more a picture of the actual physical universe than Spinoza's psychology gives us a picture of the mental and emotional life of an actual human being. But the failure of these sciences to give us a picture of the living world in no way invalidates their truth, or deprives them of their utility. Consider, as an example, Spinoza's psychological law freely expressed in the dictum that Paul's idea of Peter tells us more about Paul than about Peter. This conclusion follows strictly from fundamental principles of Spinoza's abstract, dialectical psychology; but its truth or its practical applicability is because of that not in the least impaired. Indeed, because of its dialectical form its range of meaning is greatly increased. Spinoza's dictum applies to what William James called the "psychologist's fallacy." It also applies to what John Ruskin called the "pathetic fallacy." Again, it applies to the fallacy Franz Boas exposed and which he may justly have called the "anthropologist's fallacy." And it applies also to what one may, with a great deal of benefit, dub the "ethicist's fallacy." For the very same constitutional weakness of man to identify confusedly his own nature with that of the object he is contemplating or studying, is most flagrantly and painfully evident in the fields of theoretical and practical ethics. The "ethicist's fallacy" is the source of all absolutism in theory, and all intolerance in practice. All four fallacies just enumerated come under Spinoza's dictum as special cases come under a general law. And these four are by no means the only instances of the common habit of mind. From no field of human endeavor is the mischief-working fallacy ever absent. We find it lodged in the judge's decision, the propagandist's program, the historian's record, the philosopher's system. In the field of metaphysical poetry it has recently been identified by Santayana as "normal madness." In its milder forms, the fallacy is now known by every one as the "personal equation"; in its pronounced, abnormal manifestations it is known by the psychoanalysts as "transference." It is a Protean fallacy woven into the emotional texture of the human mind. Nothing, for it, is sacred enough to be inviolate. For Spinoza discovered it sanctimoniously enshrined even in the Sacred Scriptures. As he brilliantly shows us in the _Tractatus Theologico-Politicus_, the prophets' ideas about God tell us more about the prophets than about God.