The normal objective of my thought affords no insight into the dark places of human will and feeling.

It is our American habit if we find the foundations of our educational structure unsatisfactory to add another story or wing.

I soon learned to scent out that which was able to lead to fundamentals and to turn aside from everything else, from the multitude of things which clutter up the mind and divert it from the essential.

You believe in a God who plays dice, I in complete law and order.

The time comes in life when we have read enough. It's time to stop reading. It's time to lay down the books and write.

It is this mythical, or rather symbolic, content of the religious traditions which is likely to come into conflict with science. This occurs whenever this religious stock of ideas contains dogmatically fixed statements on subjects which belong in the domain of science.

Laws alone can not secure freedom of expression; in order that every man present his views without penalty there must be spirit of tolerance in the entire population.