Avicenna

As to the mental essence, we find it in infants devoid of every mental form.

Therefore in medicine we ought to know the causes of sickness and health.

The knowledge of anything, since all things have causes, is not acquired or complete unless it is known by its causes.

Why do men fight who were born to be brothers?

Doubt is part of all religion. All the religious thinkers were doubters.

I wrote in the 'War of Art' that I could divide my life neatly into two parts: before turning pro and after. After is better.