Page:Popular Science Monthly Volume 22.djvu/212

200 which are as direct as those which are furnished by the physical sciences, instead of the general and circumstantial evidence which you adduce. The student of physics does not ask us to believe that all bodies attract each other according to the law of inverse squares until he has shown us that he is able to prove that every body we bring him does behave in this way; and the chemist shows us that he can separate every specimen of pure water which we furnish into oxygen and hydrogen before he expects us to believe that all water is compounded of these two substances. This is the sort of proof we want; something exact and specific in place of your generalizations. When you can trace back the ancestry of any man we bring you with what you call negro characteristics, tell us who his father and grandfather were, and so on, until you reach one of your negro immigrants—when you can do this with all our inhabitants, and show us that every man with these characteristics is the descendant of one of these immigrants, and that every man with European characteristics has some of the blood of one of your European immigrants in his body, you may claim that you have given us scientific proof of your hypothesis.

If that is too much to ask, trace one of our people back in this way, for it must be plain to you that, if you are not able to do this, your hypothesis is only a probability.

You trace us back for a generation or two with some exactness, but then you make a great leap to some one whom you find mentioned in history, and you trace his ancestors and descendants for a generation or two, and then comes another break. There is no certainty that he has any living descendants, nor is there any certainty that he is at all related to any of your immigrants. We acknowledge your proofs of a negro immigration, and we know that a few other negroes have come to our country from time to time, but their race soon dies out, and you must remember that we have satisfactory evidence that our race had its present character long before the time when you say the foreign elements were introduced.

Even if we grant the accuracy of all the facts which you claim to have discovered, they only show that the history which you have traced out is such a history as your hypothesis would lead you to expect, but this does not prove the truth of the hypothesis. You have only got at a few facts here and there, and future discoveries may show that you are wrong. We are glad to know about the foreign settlers, but you have by no means proved that they were ancestors of ours.

I think that this illustration gives us a fair statement of the value of the evidence for evolution which is furnished by paleontology. There is an absolute and total lack of direct proof, and there must be by the nature of the case, so there is no room to hope for the conversion of any one who is determined to reject the theory as long as doubt is possible; but the end of science is not to proselyte but to