There was a time when we wanted to be told what an electron is. The question was never answered. No familiar conceptions can be woven around the electron; it belongs to the waiting list.

We have found that where science has progressed the farthest, the mind has but regained from nature that which the mind put into nature.

Our ultimate analysis of space leads us not to a “here” and a “there,” but to an extension such as that which relates “here” and “there.” To put the conclusion rather crudely-space is not a lot of points close together; it is a lot of distances interlocked.

The quest of the absolute leads into the four-dimensional world.

The mathematics is not there till we put it there.

I don’t believe any experiment until it is confirmed by theory. I find this is a witty inversion of “conventional” wisdom.

Shuffling is the only thing which Nature cannot undo.

Never accept a fact until it has been verified by theory.

The helium which we handle must have been put together at some time and some place. We do not argue with the critic who urges that the stars are not hot enough for this process; we tell him to go and find a hotter place.

Who will observe the observers?