All our thoughts and concepts are called up by sense-experiences and have a meaning only in reference to these sense-experiences. On the other hand, however, they are products of the spontaneous activity of our minds; they are thus in no wise logical consequences of the contents of these sense-experiences. If, therefore, we wish to grasp the essence of a complex of abstract notions we must for the one part investigate the mutual relationships between the concepts and the assertions made about them; for the other, we must investigate how they are related to the experiences.

Fraulein Noether was the most significant creative mathematical genius thus far produced since the higher education of women began.

It is important to foster individuality, for only the individual can produce the new ideas.

Make everything as simple as possible, but not simpler. A man should look for what is, and not for what he thinks should be. We cannot solve our problems with the same thinking we used when we created them. A question that sometimes drives me hazy: am I or are the others crazy? Any intelligent fool can make things bigger and more complex... It takes a touch of genius - and a lot of courage to move in the opposite direction. All religions, arts and sciences are branches of the same tree. It's not that I'm so smart, it's just that I stay with problems longer.

Overpopulation in various countries has become a serious threat to the health of people and a grave obstacle to any attempt to organise peace on this planet

We should take care not to make the intellect our god; it has, of course, powerful muscles, but no personality.

There is not the slightest indication that nuclear energy will ever be obtainable. It would mean that the atom would have to be shattered at will.