The essentials of being a person of my type lies precisely in what they think and how they think, not in what they do. Your thoughts shape you.

One cannot learn so well as by experiencing it oneself.

I do not believe that a moral philosophy can ever be founded on a scientific basis. … The valuation of life and all its nobler expressions can only come out of the soul’s yearning toward its own destiny. Every attempt to reduce ethics to scientific formulas must fail. Of that I am perfectly convinced.

Isn't it strange that I who have written only unpopular books should be such a popular fellow?

Consider the concepts referred to in the words 'where', 'when', 'why', 'being', to the elucidation of which innumerable volumes of philosophy have been devoted. We fare no better in our speculations than a fish which should strive to become clear as to what is water.

It is entirely possible that behind the perception of our senses, worlds are hidden of which we are unaware.

The most beautiful thing we can experience is the mysterious. It is the source of all true art and science.