To raise new questions, new possibilities, to regard old problems from a new angle, requires creative imagination and marks real advance in science.

All our thinking is of this nature, a free play with concepts.

I thought of that while riding my bicycle.

The contemplation of this world beckoned as a liberation (...)The road to this paradise was not as comfortable and alluring as the road to the religious paradise; but it has shown itself reliable, and I have never regretted having chosen it.

Often in evolutionary processes a species must adapt to new conditions in order to survive. Today the atomic bomb has altered profoundly the nature of the world as we know it, and the human race consequently finds itself in a new habitat to which it must adapt its thinking.

The bigotry of the nonbeliever is for me nearly as funny as the bigotry of the believer.

The world we have created is a product of our thinking.