The way is difficult, and in the end all man ever attains to is _relative_ truth. But such relative truth suffices for the time being, if it serves to explain the most important actual concatenations of the past, to light up present problems, to predict those of the future, so that we are then in a position to achieve adaptation through our knowledge. But _absolute_ truth could be accessible only to omniscience, aware of all possible concatenations and combinations; that is not possible, for the concatenations and their combinations are infinite. Accordingly, we shall never know more than an approximate truth. Should new relationships be discovered, new combinations built up, then the picture changes, and with it the entire possibilities in knowledge and power. To what revolutions in daily life does not every new scientific discovery lead: how absurdly little was the beginning of our first ideas of electricity, how inconceivably great the results! Time and again it is necessary to repeat this commonplace, because one sees how life is always made bitter for the innovators in every scientific field, and now is it being made especially so for the disciples of the psychoanalytic school. Of course, every one admits the truth of this platitude so long as it is a matter of "academic" discussion, but only so long; just as soon as a concrete case has to be considered, sympathies and antipathies rush into the foreground and darken judgment. And therefore the scientist must fight tirelessly, appealing to logic and honour, for freedom of research in every field, and must not permit authority, of no matter what political or religious tinge, to advance reasons of _opportunism_ to destroy or restrict this freedom; opportunist reasons may be and are in place elsewhere, not here. Finally we must completely disavow that maxim of the Middle Ages: "_Philosophia ancilla Theologiæ_," and no less, too, the war-cries of the university class-rooms with their partisanship of one or other religious or political party. All fanaticism is the enemy of science, which must above all things be _independent_.