14. It is perhaps just dawning on five or six minds that natural philosophy is only a world-exposition and world-arrangement (according to us, if I may say so!) and NOT a world-explanation; but in so far as it is based on belief in the senses, it is regarded as more, and for a long time to come must be regarded as more—namely, as an explanation. It has eyes and fingers of its own, it has ocular evidence and palpableness of its own: this operates fascinatingly, persuasively, and CONVINCINGLY upon an age with fundamentally plebeian tastes—in fact, it follows instinctively the canon of truth of eternal popular sensualism. What is clear, what is "explained"? Only that which can be seen and felt—one must pursue every problem thus far. Obversely, however, the charm of the Platonic mode of thought, which was an ARISTOCRATIC mode, consisted precisely in RESISTANCE to obvious sense-evidence—perhaps among men who enjoyed even stronger and more fastidious senses than our contemporaries, but who knew how to find a higher triumph in remaining masters of them: and this by means of pale, cold, grey conceptional networks which they threw over the motley whirl of the senses—the mob of the senses, as Plato said. In this overcoming of the world, and interpreting of the world in the manner of Plato, there was an ENJOYMENT different from that which the physicists of today offer us—and likewise the Darwinists and anti-teleologists among the physiological workers, with their principle of the "smallest possible effort," and the greatest possible blunder. "Where there is nothing more to see or to grasp, there is also nothing more for men to do"—that is certainly an imperative different from the Platonic one, but it may notwithstanding be the right imperative for a hardy, laborious race of machinists and bridge-builders of the future, who have nothing but ROUGH work to perform.
15. To study physiology with a clear conscience, one must insist on the fact that the sense-organs are not phenomena in the sense of the idealistic philosophy; as such they certainly could not be causes! Sensualism, therefore, at least as regulative hypothesis, if not as heuristic principle. What? And others say even that the external world is the work of our organs? But then our body, as a part of this external world, would be the work of our organs! But then our organs themselves would be the work of our organs! It seems to me that this is a complete REDUCTIO AD ABSURDUM, if the conception CAUSA SUI is something fundamentally absurd. Consequently, the external world is NOT the work of our organs—?
16. There are still harmless self-observers who believe that there are "immediate certainties"; for instance, "I think," or as the superstition of Schopenhauer puts it, "I will"; as though cognition here got hold of its object purely and simply as "the thing in itself," without any falsification taking place either on the part of the subject or the object. I would repeat it, however, a hundred times, that "immediate certainty," as well as "absolute knowledge" and the "thing in itself," involve a CONTRADICTIO IN ADJECTO; we really ought to free ourselves from the misleading significance of words! The people on their part may think that cognition is knowing all about things, but the philosopher must say to himself: "When I analyze the process that is expressed in the sentence, 'I think,' I find a whole series of daring assertions, the argumentative proof of which would be difficult, perhaps impossible: for instance, that it is I who think, that there must necessarily be something that thinks, that thinking is an activity and operation on the part of a being who is thought of as a cause, that there is an 'ego,' and finally, that it is already determined what is to be designated by thinking—that I KNOW what thinking is. For if I had not already decided within myself what it is, by what standard could I determine whether that which is just happening is not perhaps 'willing' or 'feeling'? In short, the assertion 'I think,' assumes that I COMPARE my state at the present moment with other states of myself which I know, in order to determine what it is; on account of this retrospective connection with further 'knowledge,' it has, at any rate, no immediate certainty for me."—In place of the "immediate certainty" in which the people may believe in the special case, the philosopher thus finds a series of metaphysical questions presented to him, veritable conscience questions of the intellect, to wit: "Whence did I get the notion of 'thinking'? Why do I believe in cause and effect? What gives me the right to speak of an 'ego,' and even of an 'ego' as cause, and finally of an 'ego' as cause of thought?" He who ventures to answer these metaphysical questions at once by an appeal to a sort of INTUITIVE perception, like the person who says, "I think, and know that this, at least, is true, actual, and certain"—will encounter a smile and two notes of interrogation in a philosopher nowadays. "Sir," the philosopher will perhaps give him to understand, "it is improbable that you are not mistaken, but why should it be the truth?"
17. With regard to the superstitions of logicians, I shall never tire of emphasizing a small, terse fact, which is unwillingly recognized by these credulous minds—namely, that a thought comes when "it" wishes, and not when "I" wish; so that it is a PERVERSION of the facts of the case to say that the subject "I" is the condition of the predicate "think." ONE thinks; but that this "one" is precisely the famous old "ego," is, to put it mildly, only a supposition, an assertion, and assuredly not an "immediate certainty." After all, one has even gone too far with this "one thinks"—even the "one" contains an INTERPRETATION of the process, and does not belong to the process itself. One infers here according to the usual grammatical formula—"To think is an activity; every activity requires an agency that is active; consequently"... It was pretty much on the same lines that the older atomism sought, besides the operating "power," the material particle wherein it resides and out of which it operates—the atom. More rigorous minds, however, learnt at last to get along without this "earth-residuum," and perhaps some day we shall accustom ourselves, even from the logician's point of view, to get along without the little "one" (to which the worthy old "ego" has refined itself).
18. It is certainly not the least charm of a theory that it is refutable; it is precisely thereby that it attracts the more subtle minds. It seems that the hundred-times-refuted theory of the "free will" owes its persistence to this charm alone; some one is always appearing who feels himself strong enough to refute it.