[U] That this is the real battle-ground between the two philosophers is virtually admitted by Mr. Mill himself at the end of his criticism. He says:--"The whole philosophy of Sir W. Hamilton seems to have had its character determined by the requirements of the doctrine of Free-will; and to that doctrine he clung, because he had persuaded himself that it afforded the only premises from which human reason could deduce the doctrines of natural religion. I believe that in this persuasion he was thoroughly his own dupe, and that his speculations have weakened the philosophical foundation of religion fully as much as they have confirmed it."--P. 549. Mr. Mill's whole philosophy, on the other hand, is determined by the requirements of the doctrine of Necessity; and to that doctrine he intrepidly adheres, in utter defiance of consciousness, and sometimes of his own consistency. Which of the two philosophers is really "his own dupe," Mr. Mill in believing that morality and religion can exist without free will--that a necessary agent can be responsible for his acts--or Sir W. Hamilton in maintaining the contrary, is a question which the former has by no means satisfactorily settled in his own favour. [V] Hamilton, _Lectures_, vol. i, p. 29. This diametrical antagonism between the two philosophers is not limited to their first principles, but extends, as might naturally be expected, to every subordinate science of which the immediate object is mental, and not material. Logic, instead of being, as Sir W. Hamilton regards it, an _a priori_ science of the necessary laws of thought, is with Mr. Mill a science of observation, investigating those operations of the understanding which are subservient to the estimation of evidence.[W] The axioms of Mathematics, which the former philosopher regards, with Kant, as necessary thoughts, based on the _a priori_ intuitions of space and time, the latter[X] declares to be "experimental truths; generalizations from observation." Psychology, which with Hamilton is especially the philosophy of man as a free and personal agent, is with Mill the science of "the uniformities of succession; the laws, whether ultimate or derivative, according to which one mental state succeeds another."[Y] And finally, in the place of Ethics, as the science of the _a priori_ laws of man's moral obligations, we are presented, in Mr. Mill's system, with Ethology, the "science which determines the kind of character produced, in conformity to the general laws of mind, by any set of circumstances, physical and moral."[Z] [W] Mill's _Logic_. Introduction, Sec. 7. [X] _Ibid._, book ii. 5, Sec. 4. [Y] Mill's _Logic_, book vi. 4, Sec. 3. [Z] _Ibid._, book vi. 5, Sec. 4.