precisely similar organism originally struck out by the immediate fiat of Deity, so long is he justified in holding his axiom, "Contrivance must have had a contriver." For "adaptation" then becomes to our minds the synonym of "contrivance"--it being utterly inconceivable that the numberless adaptations found in any living organism could have resulted in any other way than by intelligent contrivance, at the time when this organism was in the first instance _suddenly_ introduced into its complex conditions of life. Still, as an argument, this is of course merely reasoning in a circle: we adopt a hypothesis which presupposes the existence of a Deity as the first step in the proof of his existence. I do not say that Paley committed this error expressly, but merely that if it had not been for his pre-formed conviction as to the truth of the special-creation theory, he would probably not have written his "Natural Theology." Sec. 26. Thus let us take a case of his own choosing, and the one which is adduced by him as typical of "the application of the argument." "I know of no better method of introducing so large a subject than that of comparing a single thing with a single thing; an eye, for example, with a telescope. As far as the examination of the instrument goes, there is precisely the same proof that the eye was made for vision as there is that the telescope was made for assisting it. They are both made upon the same principles, both being adjusted to the laws by which the transmission and refraction of rays of light are regulated. I speak not of the origin of the laws themselves; but these laws being fixed, the construction in both cases is adapted to them. For instance: these laws require, in order to produce the same effect, that the rays of light, in passing through water into the eye, should be refracted by a more convex surface than when it passes out of air into the eye. Accordingly we find that the eye of a fish, in that part of it called the crystalline lens, is much rounder than the eye of terrestrial animals. What plainer manifestation of design can there be than this difference?" But what, let us ask, is the proximate cause of this difference? 'The immediate volition of the Deity, manifested in special creation,' virtually answers Paley; while we of to-day are able to reply, 'The agency of natural laws, to wit, inheritance, variation, survival of the fittest, and probably of other laws as yet not discovered.' Now, of course, according to the former of these two premises, there can be no more legitimate conclusion than that the difference in question is due to intelligent and special design; but, according to the other premise, it is equally clear that no conclusion can be more unwarranted; for, under the latter view, the greater rotundity of the crystalline lens in a fish's eye no more exhibits the presence of any special design than does the adaptation of a river to the bed which it has itself been the means of excavating.