Full Idea
To try to be wise all on one's own is sheer folly.
Gist of Idea
To try to be wise all on one's own is folly
Source
La Rochefoucauld (Maxims [1663], 231)
Book Reference
Rochefoucauld,La: 'Maxims' [Penguin 1959], p.64
A Reaction
I agree strongly with this. There are counter-examples, of whom Spinoza may be the greatest, and Nietzsche thought that philosophy was essentially a solitary business, but most of us are not Spinoza or Nietzsche.