All sciences are vain and full of errors that are not born of Experience, the mother of all Knowledge.

Wrongly do men cry out against experience and with bitter re- proaches accuse her of deceitfulness. Let experience alone, and rather turn your complaints against your own ignorance, which causes you to be so carried away by your vain and insensate desires as to expect from experience things which are not within her power!

Experience is never at fault; it is only your judgment that is in error in promising itself such results from experience as are not caused by our experiments. For having given a beginning, what follows from it must necessarily be a natural development of such a beginning, unless it has been subject to a contrary influence, while, if it is affected by any contrary influence, the result which ought to follow from the aforesaid beginning will be found to partake of this contrary influence in a greater or less degree in proportion as the said influence is more or less powerful than the aforesaid beginning.

I know that many will call this useless work. Though I may not, like them, be able to quote other authors, I shall rely on that which is much greater and more worthy-on experience, the mistress of their Masters.

Those who condemn the supreme certainty of mathematics feed on confusion, and can never silence the contradictions of the sophistical sciences which lead to eternal quackery.

There are four powers: memory and intellect, desire and covetousness. The two first are mental and the others sensual. The three senses sight, hearing, and smell cannot well be prevented; touch and taste not at all.