There are moments when one feels free from one's own identification with human limitations and inadequacies. At such moments one imagines that one stands on some spot of a small planet, gazing in amazement at the cold yet profoundly moving beauty of the eternal, the unfathomable; life and death flow into one, and there is neither evolution nor destiny; only Being.

When the solution is simple, God is answering.

However we select from nature a complex [of phenomena] using the criterion of simplicity, in no case will its theoretical treatment turn out to be forever appropriate (sufficient).... I do not doubt that the day will come when [general relativity], too, will have to yield to another one, for reasons which at present we do not yet surmise. I believe that this process of deepening theory has no limits.

Experience alone can decide on truth.

Great spirits have always found violent opposition from mediocre minds. The latter cannot understand it when a man does not thoughtlessly submit to hereditary prejudices but honestly and courageously uses his intelligence.

The only justification for our concepts and systems of concepts is that they serve to represent the complex of our experiences; beyond this they have not legitimacy.

Learning is experience. Everything else is just information.