The two essays here published for the first time are separated by an interval of thirty-five years. The first and longer one was written shortly before my appointment as Max Planck's successor in Berlin, and a few months before the idea of what is now called wave mechanics began for a while to monopolise my whole interest; the second and shorter one dates from two years after my appointment as Professor Emeritus at the University of Vienna. The two are closely related in theme, and, of course, also connect with many ideas which I have publicly advocated in the intervening period.

I do not know whether it is presumptuous of me to suppose that readers will be interested in ‘my’ view of the world. The critics, not myself, will decide on this. But a gesture of decorous modesty is usually in fact a disguise for arrogance. I should prefer not to be guilty of this. Anyway, the total (I have counted) is about twenty-eight to twenty-nine thousand words. Not an excessive size for a view of the world.

There is one complaint which I shall not escape. Not a word is said here of acausality, wave mechanics, indeterminacy relations, complementarity, an expanding universe, continuous creation, etc. Why doesn't he talk about what he knows instead of trespassing on the professional philosopher's preserves? Ne sutor supra crepidam.