I think that only daring speculation can lead us further and not accumulation of facts.

People love chopping wood. In this activity one immediately sees results.

I like neither new clothes nor new kinds of food.

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

The words of language, as they are written or spoken, do not seem to play any role in my mechanism of thought. The physical entities which seem to serve as elements in thought are certain signs and more or less clear images.

Every age has its beautiful moments.

One should guard against preaching to young people success in the customary form as the main aim in life. The most important motive for work in school and in life is pleasure in work, pleasure in its result, and the knowledge of the value of the result to the community.