Now for real thorough-going dogmatism there is nothing like scientific dogmatism, there is no dogmatist like a scientific dogmatist. There are many scientific men who pretend to know absolutely that many things cannot possibly be because they have never seen them, heard them, felt them or measured them. It is because of these men, who are not many, but loud, that we scientific men as a class have a reputation among many people of being narrow-minded and bigoted; and I hasten to admit that many of us are. Not all that is called science is proved; and most certainly not all that is called non-science is disproved, or because as yet unproved is to be tossed lightly or sneeringly aside. The scientific man who declares what cannot possibly be, exposes himself as a boaster and a charlatan, for by such declaration he, by implication, claims to know all the order of nature, which certainly no man does know. No man knows all that is or may be; hence no man knows what is not or may not be. It was Weismann's new facts and new theories about heredity that did much to overthrow Lamarckism and make it possible to expand rational Darwinism into irrational ultra-Darwinism and then claim for it such an insolently dominating place among the explanations of evolution. And now it is the still newer and far less theoretical and more concrete knowledge of heredity that has dethroned Neo-Darwinism, made impossible and absurd the German claims of the _Allmacht_ of natural selection as evolution explanation, and revealed to us how little we really know of the potent causes and controls of evolution--if we may call that revelation which reveals darkness where before was apparent light. The factors of evolution that today we are more certain of than any others are the unknown factors, the causes we do not know, the methods we do not understand. If this seems to be a humiliating confession to come from a biologist and professed student of evolution, it is one in which all honest scholars must join. If the Germans will not, they are not honest.