Insofar as we may at all claim that slavery has been abolished today, we owe its abolition to the practical consequences of science

All means prove but blunt instruments, if they have not behind them a living spirit.

Whoever is careless with the truth in small matters cannot be trusted in important affairs.

Not all that counts, can be counted

There is, however, one other human right which is infrequently mentioned but which seems to be destined to become very important: this is the right, or the duty, of the individual to abstain from cooperating in activities which he considers wrong or pernicious.

God does not care about our mathematical difficulties. He integrates empirically.

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.