From a sin of omission let us pass to a sin of commission. Professor Ward quotes from me the sentence--“The absolutely homogeneous must lose its equilibrium; and the relatively homogeneous must lapse into the relatively less homogeneous.”--_First Principles_, p. 429. Then presently he writes:-- “In truth, however, homogeneity is not necessarily instability. Quite otherwise. If the homogeneity be absolute--that of Lord Kelvin’s primordial medium, say--the stability will be absolute too. In other words, if ‘the indefinite, incoherent homogeneity,’ in which, according to Mr. Spencer, some rearrangement _must result_, be a state devoid of all qualitative diversity and without assignable bounds, then, as we saw in discussing mechanical ideals, any ‘rearrangement’ can result only from external interference; it can not begin from within” (i., 223). And then he goes on to argue that “Thus, the very first step in Mr. Spencer’s evolution seems to necessitate a breach of continuity. This fatal defect, &c.” (_ibid._). Observe the words “without assignable bounds”--without knowable limits, infinite. So that the law of the instability of the homogeneous is disposed of because it does not apply to an infinite homogeneous medium. But since infinity is inconceivable by us, this alleged case of stable homogeneity is inconceivable too. Hence the proposal is to shelve the law displayed in all things we know, because it is inapplicable to a hypothetical thing we can not know, and can not even conceive! Now let me turn to the essential point. This nominally-exceptional case was fully recognized by me in the chapter he is criticising. In § 155 of _First Principles_ (p. 429), it is written:-- “One stable homogeneity only, is hypothetically possible. If centers of force, absolutely uniform in their powers, were diffused with absolute uniformity through unlimited space, they would remain in equilibrium. This, however, though a verbally intelligible supposition, is one that can not be represented in thought; since unlimited space is inconceivable.” So that this nominal exception which Professor Ward urges against me as a “fatal defect,” was set forth by me thirty-seven years ago! A somewhat more involved case may next be dealt with. Professor Ward writes:-- “Moreover, on the physical assumption from which Mr. Spencer sets out, viz., that the mass of the universe and the energy of the universe are fixed in quantity--which ought to mean are finite in quantity--there can be no such alternations [of evolution and dissolution] as he supposes” (i., 192). After some two pages of argument, he goes on:--