Now, after these explicit statements that we have an intuitive knowledge of matter and mind--a direct and immediate consciousness of self as a real, "self-subsisting entity," and a knowledge of "an external reality, immediately and _in itself_," it seems unaccountably strange that Hamilton should assert "_that all human knowledge, consequently all human philosophy, is only of the Relative or Phenomenal_;"[290] and that "_of existence absolutely and in itself we know nothing_."[291] Whilst teaching that the proper sphere and aim of philosophy is to trace secondary causes up to ultimate or first causes, and that it _necessarily tends_ towards one First and Ultimate Cause, he at the same time asserts that "first causes do not lie within the reach of philosophy,"[292] and that it can never attain to the knowledge of the First Cause.[293] "The Infinite God can not, by us, be comprehended, conceived, or thought."[294] God, as First Cause, as infinite, as unconditioned, as eternal, is to us absolutely "_The Unknown_." The science of Real Being--of Being _in se_--of self-subsisting entities, is declared to be impossible. All science is only of the phenomenal, the conditioned, the relative. Ontology is a delusive dream. Thus, after pages of explanations and qualifications, of affirmations and denials, we find Hamilton virtually assuming the same position as Comte and Mill--_all human knowledge is necessarily confined to phenomena_. [Footnote 290: "Lectures on Metaphysics," vol. i. p. 136] [Footnote 291: Ibid., vol. i. p. 138.] [Footnote 292: Ibid., vol. i. p. 58.] [Footnote 293: Ibid., vol. i. p. 60.] [Footnote 294: Ibid., vol. ii. p. 375.] It has been supposed that the chief glory of Sir William Hamilton rested upon his able exposition and defense of the doctrine of Natural Realism. There are, however, indications in his writings that he regarded "the Philosophy of the Conditioned" as his grand achievement. The Law of the Conditioned had "not been generalized by any previous philosopher;" and, in laying down that law, he felt that he had made a new and important contribution to speculative thought. The principles upon which this philosophy is based are: 1. _The Relativity of all Human Knowledge._--Existence is not cognized absolutely and in itself, but only under special modes which are related to our faculties, and, in fact, determined by these faculties themselves. All knowledge, therefore, is _relative_--that is, it is of phenomena only, and of phenomena "under modifications determined by our own faculties." Now, as the Absolute is that which exists out of all relation either to phenomena or to our faculties of knowledge, it can not possibly be _known_.