Physics is experience, arranged in economical order.

Man is pre-eminently endowed with the power of voluntarily and consciously determining his own point of view.

When I recall today my early youth, I should take the boy that I then was, with the exception of a few individual features, for a different person, were it not for the existence of the chain of memories.

I can accept the theory of relativity as little as I can accept the existence of atoms and other such dogmas.

Ordinarily pleasure and pain are regarded as different from sensations.

Thing, body, matter, are nothing apart from the combinations of the elements, - the colours, sounds, and so forth - nothing apart from their so-called attributes.

The presentations and conceptions of the average man of the world are formed and dominated, not by the full and pure desire for knowledge as an end in itself, but by the struggle to adapt himself favourably to the conditions of life.