To repeat abstractly, universally, and distinctly in concepts the whole inner nature of the world , and thus to deposit it as a reflected image in permanent concepts always ready for the faculty of reason , this and nothing else is philosophy.
As the biggest library if it is in disorder is not as useful as a small but well-arranged one, so you may accumulate a vast amount of knowledge but it will be of far less value to you than a much smaller amount if you have not thought it over for yourself; because only through ordering what you know by comparing every truth with every other truth can you take complete possession of your knowledge and get it into your power. You can think about only what you know, so you ought to learn something; on the other hand, you can know only what you have thought about.
A poet or philosopher should have no fault to find with his age if it only permits him to do his work undisturbed in his own corner; nor with his fate if the corner granted him allows of his following his vocation without having to think about other people.
The real meaning of persona is a mask, such as actors were accustomed to wear on the ancient stage; and it is quite true that no one shows himself as he is, but wears his mask and plays his part. Indeed, the whole of our social arrangements may be likened to a perpetual comedy; and this is why a man who is worth anything finds society so insipid, while a blockhead is quite at home in it.
I have not yet spoken my last word about women. I believe that if a woman succeeds in withdrawing from the mass, or rather raising herself from above the mass, she grows ceaselessly and more than a man.
Happiness of any given life is to be measured, not by its joys and pleasures, but by the extent to which it has been free from suffering-from positive evil.
Descartes is rightly regarded as the father of modern philosophy primarily and generally because he helped the faculty of reason to stand on its own feet by teaching men to use their brains
in place whereof the Bible, on the one hand, and Aristotle, on the other, had previously served.
The first forty years of our life give the text, the next thirty furnish the commentary upon it, which enables us rightly to understand the true meaning and connection of the text with its moral and its beauties.