I admit that thoughts influence the body.

The truth of a theory is in your mind, not in your eyes.

The belief in an external world independent of the perceiving subject is the basis of all natural science. Since, however, sense perception only gives information of this external world or of "physical reality" indirectly, we can only grasp the latter by speculative means. It follows from this that our notions of physical reality can never be final. We must always be ready to change these notions - that is to say, the axiomatic basis of physics - in order to do justice to perceived facts in the most perfect way.

Where there is love, there is no imposition.

Man, surrounded by facts, permitting himself no surprise, no intuitive flash, no great hypothesis, no risk, is in a locked cell. Ignorance cannot seal the mind and imagination more securely.

... on principle, it is quite wrong to try founding a theory on observable magnitudes alone. In reality the very opposite happens. It is the theory which decides what we can observe.

I do not much believe in education. Each person ought to be his or her own model, however frightful that may be.