My friend...care for your psyche...know thyself, for once we know ourselves, we may learn how to care for ourselves.

Wisdom is knowing what you don't know.

Knowing thyself is the height of wisdom.

The more I learn, the less I realize I know.

I am a fool, but I know I'm a fool and that makes me smarter than you.

The man who is truly wise knows that he knows very little.