Science is the record of dead religions.
Metaphysics is a dark ocean without shores or lighthouse, strewn with many a philosophic wreck.
Philosophy consists very largely of one philosopher arguing that all others are jackasses. He usually proves it, and I should add that he also usually proves that he is one himself.
Most institutions demand unqualified faith; but the institution of science makes skepticism a virtue.
There are in fact two things, science and opinion; the former begets knowledge, the latter ignorance.
The beginning of wisdom is found in doubting; by doubting we come to the question, and by seeking we may come upon the truth.
This only is certain, that there is nothing certain; and nothing more miserable and yet more arrogant than man.
Happy is he who gets to know the reasons for things.