Full Idea
When the soul quarrels with knowledge or opinion or reason, its natural ruling principles, you have there what I call 'folly'.
Gist of Idea
It is foolish to quarrel with the mind's own reasoning processes
Source
Plato (The Laws [c.349 BCE], 689b)
Book Reference
Plato: 'The Laws', ed/tr. Saunders,Trevor J [Penguin 1970], p.136