Only the Catholic Church protested against the Hitlerian onslaught on liberty. Up till then I had not been interested in the Church, but today I feel a great admiration for the Church, which alone has had the courage to struggle for spiritual truth and moral liberty

Freedom of teaching and of opinion in book or press is the foundation for the sound and natural development of any people.

I hate crowds and making speeches. I hate facing cameras and having to answer to a crossfire of questions. Why popular fancy should seize upon me, a scientist, dealing in abstract things and happy if left alone, is a manifestation of mass psychology that is beyond me.

Science is the century-old endeavor to bring together by means of systematic thought the perceptible phenomena of this world into as thorough-going an association as possible.

The school has always been the most important means of transferring the wealth of tradition from one generation to the next. This applies today in an even higher degree than in former times, for through modern development of economic life, the family

We must learn to see the world anew.

Academic chairs are many, but wise and noble teachers are few; lecture-rooms are numerous and large, but the number of young people who genuinely thirst after truth and justice is small