There are two modes of argument presented by Theists, and by which, separately or combined, they seek to demonstrate the being of a God. These are familiarly known as the arguments _à priori and à posteriori._ The _à posteriori_ argument has been popularised in England by Paley, who has ably endeavored to hide the weakness of his demonstration under an abundance of irrelevant illustrations. The reasoning of Paley is very deficient in the essential points where it most needed strength. It is utterly impossible to prove by it the eternity or infinity of Deity. As an argument founded on analogy, the design argument, as the best, could only entitle its propounder to infer the existence of a finite cause, or rather of a multitude of finite causes. It ought not to be forgotten that the illustrations of the eye, the watch, and the man, even if admitted as instances of design, or rather of adaptation, are instances of eyes, watches, and men, designed or adapted out of pre-existing substance, by a being of the same kind of substance, and afford, therefore, no demonstration in favor of a designer alleged to have actually created substance out of nothing, and also alleged to have created a substance entirely different from himself. The illustrations of alleged adaptation or design in animal life in its embryonic stages are thus dealt with by the late George Henry Lewes: “What rational interpretation can be given to the succession of phases each embryo is forced to pass through? None of these phases have any adaptation to the future state of the animal, but are in positive contradiction to it, or are simply purposeless; many of them have no adaptation, even in its embryonic state. What does the fact imply? There is not a single known organism which is not developed out of simpler forms. Before it can attain the complex structure which distinguishes it, there must be an evolution of forms which distinguish the structures of organisms lower in the series. On the hypothesis of a plan which pre-arranged the organic world, nothing could be more unworthy of a supreme intelligence than this inability to construct an organism at once, without making several tentative efforts, undoing to-day what was so carefully done yesterday, and repeating for centuries the same tentatives and the same corrections in the same succession. Do not let us blink this consideration. There is a traditional phrase which is in vogue amongst Anthropomorphists—a phrase which has become a sort of argument—the ‘Great Architect.’ But if we are to admit the human point of view, a glance at the facts of embryology must produce very uncomfortable reflexions. For what shall we say to an architect who was unable—or, being able, was obstinately unwilling—to erect a palace, except by first using his materials in the shape of a hut, then pulling them down and rebuilding them as a cottage, then adding storey to storey, and room to room, not with any reference to the ultimate