a philosopher
Examples
My advice to you is get married: if you find a good wife you'll be happy; if not, you'll become a philosopher.
Shall I show you the sinews of a philosopher 'What sinews are those' A will undisappointed evils avoided powers daily exercised careful resolutions unerring decisions.
A philosopher is a blind man in a dark room looking for a black cat that isn't there. A theologian is the man who finds it.
Keep quiet and people will think you a philosopher.
Beard and cloak do not make one a philosopher.
If wisdom is measured by the size of the beard then the goat is a philosopher king.