There is nothing so extreme that is not allowed by the custom of some nation or other.

Wonder is the foundation of all philosophy; research, the progress; ignorance, the end. There is, by heavens, a strong and generous kind of ignorance that yields nothing, for honour and courage, to knowledge: an ignorance to conceive which needs no less knowledge than to conceive knowledge.

Thus we should beware of clinging to vulgar opinions, and judge things by reason's way, not by popular say.

The perpetual work of your life is but to lay the foundation of death.

Oh senseless man, who cannot possibly make a worm or a flea and yet will create Gods by the dozen!

Since philosophy is the art which teaches us how to live, and since children need to learn it as much as we do at other ages, why do we not instruct them in it?

All the world knows me in my book, and my book in me.