Ridicule is the best test of truth.
In seeking wisdom thou art wise; in imagining that thou hast attained it - thou art a fool.
Young men are apt to think themselves wise enough, as drunken men are apt to think themselves sober enough.
Let blockheads read what blockheads wrote.
You will find that reason, which always ought to direct mankind, seldom does; but that passions and weaknesses commonly usurp its seat, and rule in its stead.
We are really so prejudiced by our educations, that, as the ancients deified their heroes, we deify their madmen.
Common sense (which, in truth, is very uncommon) is the best sense I know of: abide by it; it will counsel you best.