Although in recent times the human mind had demonstrated its positive faculty of understanding in natural sciences, especially by inventions, still it was prejudiced by religious improbabilities in its great premises dealing with the essence of things and men, with the "good, true, and beautiful," as the ancients called it. In order to end his doubts, Descartes elevates radical doubt to the position of a principle and of a starting point for all understanding. Then he cannot doubt that he is at least searching for truth. He who does not believe in any understanding, any science, any inventions, cannot doubt at all events that the impulse for understanding is there. It, at least, is undeniable. _Cogito, ergo sum_--I think, therefore I am--that is a premise which cannot be shaken. The rest, thinks Descartes, may be deducted by Aristotlean methods. With this thought, the philosopher of modern times relapsed into the old error that anything positively true could be ascertained with logical formulas. His consciousness of the thoughts stirring in his brain, I might say his flesh and blood, convinced him by matter-of-fact evidence of the reality of their existence. This fact had hitherto been misunderstood. It is claimed that Descartes could convince himself only of the existence of his soul, of his thought, by evidence. No, my feeling, my sight, my hearing, etc., are just as evident to me as my thinking, and simultaneously with sight and hearing that which is heard and seen. The separation of subject and object can and must be merely a formality. The Descartian thesis has been distorted into the statement that nothing is evident to man but his own subjective conception. And the ideology has been carried to the extreme of calling the whole world an idea, a phantasmagoria. True, Descartes needed God in order to be sure that his conceptions did not cheat him. In order to prove that we no longer need such extravagant means in our times, I shall devote another chapter to this subject. XIV CONTINUATION OF THE DISCUSSION ON THE DIFFERENCE BETWEEN DOUBTFUL AND EVIDENT UNDERSTANDING Let us divide the history of civilization into two periods. In the first, the less civilized period, the doubtful perceptions predominate, in the second period the evident ones. Our special investigation of the correct way of evident understanding began in the first period in which the doubtful perceptions, commonly called errors, predominated. In this period, the gods rule in heaven and imagination on earth.