Observe your enemies, for they first find out your faults.
The investigation of the meaning of words is the beginning of education.
As rust corrupts iron, so envy corrupts man.
I am sadly afraid that I must have done some wicked thing.
The advantages of philosophy? That I am able to hold converse with myself.
We must not contradict, but instruct him that contradicts us; for a madman is not cured by another running mad also.