A conviction akin to religious feeling of the rationality or intelligibility of the world lies behind all scientific work of a high order.

One has a feeling that one has a kind of home in this timeless community of human beings that strive for truth. ... I have always believed that Jesus meant by the Kingdom of God the small group scattered all through time of intellectually and ethically valuable people.

It is true that the grasping of truth is not possible without empirical basis. However, the deeper we penetrate and the more extensive and embracing our theories become the less empirical knowledge is needed to determine those theories.

[Asked about a book in which 100 Nazi professors charged him with scientific error.] Were I wrong, one professor would have been quite enough.

Mere unbelief in a personal God is no philosophy at all.

It is humankind's duty to respect all life, not only animals have feelings but even also trees and plants.

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.