[11] The difference between Aristotle and Kant in ethics is sometimes expressed (see Trendelenburg, Hist. Beiträge zur Phil., iii. 171 ff.) as if it consisted in the fact that the former investigated human nature in order to find its τέλος (~telos~), whereas the latter sought the standard of action in a transcendental ground. There is reason for this distinction in Kant's manner of statement. But both may be regarded as investigating human nature. Their difference rather consists in the different position and function assigned to reason in man. It is because Kant is for the moment looking upon reason as something distinct from human nature that he says that "the ground of obligation is to be sought, not in the nature of man or in the circumstances in the world in which he is placed, but _à priori_ simply in the notions of pure reason" (Werke, iv. 237). His "metaphysical" view of ethics, however, follows from the rational constitution of the human subject and his experience, and does not depend on any source that really "transcends" the reason of man. [12] Opinion is also divided according to the place assigned to reason in the world,--this principle of division corresponding almost exactly with the former. [13] Thus it is the object of Helvétius's first _discours_ "De l'esprit" to prove that physical sensibility and memory are the only productive causes of our ideas. [14] Comte, by connecting ethics with biology; Darwin and Spencer, by the doctrine of evolution. PART I. THE INDIVIDUALISTIC THEORY. CHAPTER II. EGOISM. [Sidenote: Definition of Naturalism.] It is difficult to give an exact definition or even description of what I have called the "natural" view of man. Perhaps it may be best defined, negatively, as the view which denies to reason any spontaneous or creative function in the human constitution. For this definition, if it still leaves the positive description wanting, will at least make the classification into "natural" and "rational" exhaustive and mutually exclusive. At the same time it is to be noted that, on the theory of Naturalism, reason is not supposed to be excluded from all share in determining questions of conduct or the choice of ends. It would, indeed, be impossible to have even the pretence of an ethical theory without a certain use of reason. But its function, in this case, is limited to the merely formal one of bringing different presentations (or objects) and feelings into connection, and comparing the different states of mind thus formed with one another, not with a reason-given standard. [Sidenote: Psychological hedonism.]