Science is a wonderful thing if one does not have to earn one's living at it. One should earn one's living by work of which one is sure one is capable. Only when we do not have to be accountable to anybody can we find joy in scientific endeavor.
The ideals which have always shone before me and filled me with the joy of living are goodness, beauty, and truth. To make a goal of comfort or happiness has never appealed to me; a system of ethics built on this basis would be sufficient only for a herd of cattle.
I do not at all believe in human freedom in the philosophical sense... Schopenhauer’s saying, ‘A man can do what he wants, but not will what he wants,’ has been a very real inspiration to me since my youth; it has been a continual consolation in the face of life’s hardships, my own and others’, and an unfailing wellspring of tolerance. This realization mercifully mitigates the easily paralyzing sense of responsibility and prevents us from taking ourselves and other people too seriously; it is conducive to a view of life which, in part, gives humour its due.
I believe in mystery and, frankly, I sometimes face this mystery with great fear. In other words, I think that there are many things in the universe that we cannot perceive or penetrate, and that also we experience some of the most beautiful things in life only in a very primitive form. Only in relation to these mysteries do I consider myself to be a religious man.
Every one who is seriously involved in the pursuit of science becomes convinced that a spirit is manifest in the laws of the Universe-a spirit vastly superior to that of man, and one in the face of which we with our modest powers must feel humble.
Out of the multitude of our sense experiences we take, mentally and arbitrarily, certain repeatedly occurring complexes of sense impression (partly in conjunction with sense impressions which are interpreted as signs for sense experiences of others), and we attribute to them a meaning the meaning of the bodily object.
The theoretical idea ... does not arise apart from and independent of experience; nor can it be derived from experience by a purely logical procedure. It is produced by a creative act. Once a theoretical idea has been acquired, one does well to hold fast to it until it leads to an untenable conclusion.