Hamilton calls this "the great axiom" of philosophy. That we may distinctly comprehend its meaning, and understand its bearing on the subject under discussion, we must ascertain the sense in which he uses the words "_phenomenal_" and "_relative._" The importance of an exact terminology is fully appreciated by our author; and accordingly, in three Lectures (VIII., IX., X.), he has given a full explication of the terms most commonly employed in philosophic discussions. Here the word "_phenomenon_" is set down as the necessary "_correlative_" of the word "_subject_" or "_substance_." "These terms can not be explained apart, for each is correlative of the other, each can be comprehended only in and through its correlative. The term '_subject_' is used to denote the unknown (?) basis which lies under the various _phenomena_ or properties of which we become aware, whether in our external or internal experience."[299] "The term '_relative_' is _opposed_ to the term '_absolute_;' therefore, in saying that we know only the relative, I virtually assert that we know nothing absolutely, that is, _in and for itself, and without relation to us and our faculties_."[300] Now, in the philosophy of Sir William Hamilton, "the absolute" is defined as "that which is aloof from relation"--"that which is out of all relation."[301] The _absolute_ can not, therefore, be "_the correlative_" of the conditioned--can not stand in any relation to the phenomenal. The _subject,_ however, is the necessary correlative of the phenomenal, and, consequently, the subject and the absolute are not identical. Furthermore, Hamilton tells us the subject _may be comprehended_ in and through its correlative--the phenomenon; but the absolute, being aloof from all relation, can not be comprehended or conceived at all. "The subject" and "the absolute" are, therefore, not synonymous terms; and, if they are not synonymous, then their antithetical terms, "phenomenal" and "relative," can not be synonymous. [Footnote 299: "Lectures on Metaphysics," vol. i. p. 148.] [Footnote 300: Ibid., vol. i. p. 137.] [Footnote 301: "Discussions," p. 21.]