There is no space without aether, and no aether which does not occupy space.

So far as physics is concerned, time's arrow is a property of entropy alone.

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

A hundred thousand million Stars make one Galaxy; A hundred thousand million Galaxies make one Universe. The figures may not be very trustworthy, but I think they give a correct impression.

It is impossible to trap modern physics into predicting anything with perfect determinism because it deals with probabilities from the outset.

Let us suppose that an ichthyologist is exploring the life of the ocean. He casts a net into the water and brings up a fishy assortment. Surveying his catch, he proceeds in the usual manner of a scientist to systematise what it reveals. He arrives at two generalisations: No sea-creature is less than two inches long. (2) All sea-creatures have gills. These are both true of his catch, and he assumes tentatively that they will remain true however often he repeats it.

There is only one law of Nature-the second law of thermodynamics-which recognises a distinction between past and future more profound than the difference of plus and minus. It stands aloof from all the rest. ... It opens up a new province of knowledge, namely, the study of organisation; and it is in connection with organisation that a direction of time-flow and a distinction between doing and undoing appears for the first time.