The more I see the less I know for sure.

What is important is not the quantity of your knowledge but its quality. You can know many things without knowing the most important.

One whose knowledge is confined to books and whose wealth is in the possession of others, can use neither his knowledge nor wealth when the need for them arises.

Understanding a question is half an answer.

It's not that I'm so smart; it's just that I stay with problems longer.

Any attempts at autobiography before the age of eighty seem pretty self-involved to me. There are a lot of smart middle aged people but not many wise ones.