Except our own thoughts, there is nothing absolutely in our power.

If I simply refrain from making a judgment in cases where I do not perceive the truth with sufficient clarity and distinctness, then it is clear that I am behaving correctly and avoiding error.

I am accustomed to sleep and in my dreams to imagine the same things that lunatics imagine when awake.

Your joy is your sorrow unmasked. And the self-same well from which your laughter rises was often-times filled with your tears.

I hope that posterity will judge me kindly, not only as to the things which I have explained, but also to those which I have intentionally omitted so as to leave to others the pleasure of discovery.

Let whoever can do so deceive me, he will never bring it about that I am nothing, so long as I continue to think I am something.

Even the mind depends so much on temperament and the disposition of one's bodily organs that, if it is possible to find a way to make people generally more wise and more skilful than they have been in the past, I believe that we should look for it in medicine. It is true that medicine as it is currently practiced contains little of much use.