[41] Mr. Spencer makes a distinction between conceiving myself looking into darkness, and conceiving _that I am_ then and there looking into darkness. To me it seems that this change of the expression to the form _I am_, just marks the transition from conception to belief, and that the phrase "to conceive that _I am_," or "that anything _is_," is not consistent with using the word conceive in its rigorous sense. [42] I have myself accepted the contest, and fought it out on this battleground, in the eleventh chapter of _An Examination of Sir William Hamilton's Philosophy_. [43] _Discussions_, &c., 2nd ed. p. 624. [44] If it be said that the _existence_ of matter is among the things proved by the principle of Excluded Middle, that principle must prove also the existence of dragons and hippogriffs, because they must be either scaly or not scaly, creeping or not creeping, and so forth. [45] For further considerations respecting the axioms of Contradiction and Excluded Middle, see the twenty-first chapter of _An Examination of Sir William Hamilton's Philosophy_. [46] Mr. De Morgan says "Plato," but to prevent confusion I have kept to my own _exemplum_. BOOK III. OF INDUCTION. "According to the doctrine now stated, the highest, or rather the only proper object of physics, is to ascertain those established conjunctions of successive events, which constitute the order of the universe; to record the phenomena which it exhibits to our observations, or which it discloses to our experiments; and to refer these phenomena to their general laws."--D. STEWART, _Elements of the Philosophy of the Human Mind_, vol. ii. chap. iv. sect. 1. CHAPTER I. PRELIMINARY OBSERVATIONS ON INDUCTION IN GENERAL.