The doctrine that the universe is an automatic machine,--self-originated and self-sustained--undoubtedly rests upon a principle formally recognized by some evolutionists, as the "Law of Continuity," and taken for granted by many who do not put it into words. This principle is,--that everything must always have happened according to the same laws of Nature which operate now; that there can never have been a "miracle," understanding by this term whatever is beyond the scope of natural forces; and that, accordingly, the whole of the world's history,--one stage as much as another,--falls within the province of Science. By no one has this position been more clearly stated than by the late Professor Romanes. All minds [he tells us][43] with any instincts of science in their composition have grown to distrust, on merely antecedent grounds, any explanation which embodies a miraculous element. Such minds have grown to regard all these explanations as mere expressions of our own ignorance of natural causation; or, in other words, they have come to regard it as an _à priori_ truth that nature is always uniform in respect of method or causation; that the reign of law is universal; the principle of continuity ubiquitous. He goes on to declare that "The fact of evolution--or, which is the same thing, the fact of continuity in natural causation--has now been undoubtedly proved in many departments of nature," and that, in particular, "throughout the range of inorganic nature" it is "a demonstrated fact." If this be so, it must necessarily follow that the Laws of Nature, as Science finds them operating, sufficiently explain not only all that happens in our present world, but also all that must have happened while this world was being produced. According to what has already been said, by "The Law of Continuity" no more can be signified than that Continuity is a fact, that the world has actually come to be what it is through the continual operation of just the same natural forces as we find at work to-day. That things _did_ so happen we have not and cannot have, direct evidence; for no witness was there to report. We can but draw inferences from the present to the past, and argue that what Nature does to-day, she must have been capable of doing yesterday and the day before. Only thus can continuity of natural laws possibly be established. It would obviously be vain to argue that we must suppose no other forces ever to have acted than those we can observe, because, for all we know, other conditions may so have altered as to make their results altogether different from any of which we have experience. It is likewise manifest that if we are to speak of demonstrated facts, and of conclusions placed beyond rational possibility of doubt, proofs must be forthcoming sufficient to compel scientific assent.