Descartes, in spite of, or perhaps because of, his training at a school of the Jesuits, seems to have caught the spirit, the real meaning of his time, getting behind the mere letter of their instruction and of their point of view. Only mathematics gave him any satisfaction, and he left the La Flêche school in the first place conscious that he had learned little or nothing, in the second place curious about the possibility of men ever knowing anything, and in the third place evidently through the influence of mathematics strongly prejudiced in favour of introspection, or of thought conducted independently of things, as the only possible way to certainty. This education, then, and its outcome, true as it was to the life of the day, fitted Descartes for his life work, which was nothing more or less than the erection of a system of philosophy on the basis of a thorough-going confession of doubt. Descartes entered upon his great task by taking his day at its word. St. Paul, addressing the Athenians, reminding them of one of their own temples, and quoting their own poet Aratus, was not more tactful. [p.182] Thus, as if speaking directly to the sceptics about him, Descartes doubted everything, because he found, not only in his own consciousness, become too reflective for implicit belief, but also in the wide experience of his race, that everything was dubitable. He doubted church and state, science and society; and he went even farther than this. Also he boldly doubted mathematics, so long his own support and the reliance of many others in his time. He did not know surely that there might not be an evil spirit in the universe, a spirit of deception, which even in mathematics was obscuring the mind's vision, making it see things not as they are, but as they are not. Deception was real enough and obvious enough in life at large to make such a suspicion as this at least plausible. Moreover, the notion of an agent of evil in the world had been a commonplace for centuries. It was just a part of that medieval training. So although nothing could be said with certainty either way, the plausible mischance had to be faced; mathematics went the way of all doubtful knowledge, and man was left with literally nothing but his doubt, his universal doubt. "_Dubito_," said Descartes; "to doubt is my inmost nature"; and speaking so he at once marked the first step in his reasoning, so important then and now, and in the simplicity and directness of real genius reported a great, deep fact of his own experience and of that of his time.