Strange! I don't understand how it is that we can write mathematical expressions and calculate what the thing is going to do without being able to picture it.

The basis of action on love, the brotherhood of all men, the value of the individual... the humility of the spirit.

There are thousands of years in the past, and there is an unknown amount of time in the future. There are all kinds of opportunities, and there are all kinds of dangers.

The test of all knowledge is experiment.

Don't think about what you want to be, but what you want to do. Keep up some kind of a minimum with other things so that society doesn't stop you from doing anything at all.

I am going to tell you what nature behaves like. If you will simply admit that maybe she does behave like this, you will find her a delightful, entrancing thing. Do not keep saying to yourself, if you can possibly avoid it, 'But how can it be like that?' ...Nobody knows how it can be like that.

One does not, by knowing all the physical laws as we know them today, immediately obtain an understanding of anything much. I love only nature, and I hate mathematicians.