Who is called a fool indeed.

Yo bālo maññati bālyaṃ, paṇḍito vāpi tena so;

Bālo ca paṇḍitamānī, sa ve ‘‘bālo’’ti vuccati.

The fool aware of his folly, in so far is wise.

But the fool who thinks himself wise, is called a fool indeed.

Dhammapada, 63.