If man has had a high antiquity on this earth, science will find it out and prove it beyond a doubt. If he has not had such antiquity, science will discover that too, and prove it. All we have to do is to let science have her way. Another remark which we make here, is respecting the power which a _single fact_ may have in this investigation. It is not often that great questions in history, or social polity, or jurisprudence are determined by a single fact. The great results of history, economics, and law are effected by the converging power of many facts. So also in science. Its great results are determined by the accumulated power of multitudinous facts. Its final categories are fixed by abundant certainties and manifold inductions. And yet it may sometimes occur that a single fact may be of such a nature that there is no escaping the conclusion which it forces upon the mind. It may concentrate in itself all the elements of certainty usually obtained from many sources. It may be determinative in its very nature, and admit of scepticism only at the expense of rationality. A single human grave, with its entombed skeleton, discovered in some uninhabited waste, where it was never known the foot of man had trod, would prove conclusively that human footsteps had once trod there. The discovery of a single weapon of the quality and temper of the Damascus blade amid the ruins of a buried city, would prove as fully as would the discovery of a thousand that the people of that age of the world understood the methods of working steel. One canoe found moored to the bank of the Delaware, the Schuylkill, or the Susquehanna, when the white man began to penetrate this continent, would have been sufficient to prove that the aborigines understood, to that extent, the art of navigation. So in science, one fossil of a different species from any found heretofore in a certain deposit is sufficient to add another to the forms of life represented by that deposit. One fossil found lower in the geological scale than life was supposed to have begun on this planet, is sufficient to prove that it had a still earlier beginning. So with regard to contemporary forms of life, one fact may be sufficient to warrant or compel a conclusion. Hugh Miller cites the instance of fossil dung being found as proving to the anti-geologists that these fossils were once real living creatures, and not mere freaks of nature. The instance might not be thought conclusive, for if the Author of nature saw fit to amuse himself by making the semblances of huge iguanodons, elephants, and hippopotami, in the solid rocks, it might readily be supposed that He would extend His amusement to the making of fossil dung.[2] But now, if in the fossil entrails of the cave hyena the bones of a hare should be found, it would prove conclusively to any but an anti-geologist, that the hare lived contemporaneously with the hyena.