To lie is vile, to tell truth is excellent, if not noble.

I am not poor. Poor are those who desire many things.

Anyone who conducts an argument by appealing to authority is not using his intelligence; he is just using his memory.

Given the cause nature produces the effect in the briefest manner that it can employ.

One painter ought never to imitate the manner of any other; because in that case he cannot be called the child of nature, but the grandchild. It is always best to have recourse to nature, which is replete with such abundance of objects, than to the productions of other masters, who learnt everything from her.

The faculty of imagination is both the rudder and the bridle of the senses.

No human investigation can claim to be scientific if it doesn't pass the test of mathematical proof.