Experience is a good school. But the fees are high.
It is probably safe to say that all the changes of factual knowledge which have led to the relativity theory, resulting in a very great theoretical development, are completely trivial from any point of view except their relevance to the structure of a theoretical system.
Music played at weddings always reminds me of the music played for soldiers before they go into battle.
You will seek not a near but a distant objective, and you will not be satisfied with what you may have done.
When words leave off, music begins.
In earlier religions the spirit of the time was expressed through the individual and confirmed by miracles. In modern religions the spirit is expressed through the many and confirmed by reason.
But the fact a person denies that he is theorising is no reason for taking him at his word and failing to investigate what implicit theory is involved in his statements.
Iron sharpens iron; scholar, the scholar.
If observed facts of undoubted accuracy will not fit any of the alternatives it leaves open, the system itself is in need of reconstruction.
He who dares not reason, is a slave.