Is not this same thing the cause of the confidence of men in positive critical-experimental science, and of the devout attitude of the crowd towards that which it preaches? At first it seems strange, that the theory of evolution can in any manner justify people in their evil ways; and it seems as though the scientific theory of evolution has to deal only with facts, and that it does nothing else but observe facts. But this only appears to be the case. Exactly the same thing appeared to be the case with the Hegelian doctrine, in a greater degree, and also in the special instance of the Malthusian doctrine. Hegelianism was, apparently, occupied only with its logical constructions, and bore no relation to the life of mankind. Precisely this seemed to be the case with the Malthusian theory. It appeared to be busy itself only with statistical data. But this was only in appearance. Contemporary science is also occupied with facts alone: it investigates facts. But what facts? Why precisely these facts, and no others? The men of contemporary science are very fond of saying, triumphantly and confidently, "We investigate only facts," imagining that these words contain some meaning. It is impossible to investigate facts alone, because the facts which are subject to our investigation are _innumerable_ (in the definite sense of that word),--innumerable. Before we proceed to investigate facts, we must have a theory on the foundation of which these or those facts can be inquired into, i.e., selected from the incalculable quantity. And this theory exists, and is even very definitely expressed, although many of the workers in contemporary science do not know it, or often pretend that they do not know it. Exactly thus has it always been with all prevailing and guiding doctrines. The foundations of every doctrine are always stated in a theory, and the so-called learned men merely invent further deductions from the foundations once stated. Thus contemporary science is selecting its facts on the foundation of a very definite theory, which it sometimes knows, sometimes refuses to know, and sometimes really does not know; but the theory exists.