Our reliance on the validity of a scientific conclusion depends ultimately on a judgment of coherence; and as there can exist no strict criterion for coherence, our judgment of it must always remain a qualitative, nonformal, tacit, personal judgment.

Personal participation is the universal principle of knowing.

We do not accept a religion because it offers us certain rewards. The only thing that a religion can offer us is to be just what it, in itself, is: a greater meaning in ourselves, in our lives, and in our grasp of the nature of things...a religion exists for us only if, like a piece of poetry, it carries us away. It is not in any sense a 'hypothesis.

No inanimate object is ever fully determined by the laws of physics and chemistry.

These maxims and the art of interpreting them may be said to constitute the premisses of science but I prefer to call them our scientific beliefs. These premisses or beliefs are embodied in a tradition, the tradition of science.

I hold that the propositions embodied in natural science are not derived by any definite rule from the data of experience, and that they can neither be verified nor falsified by experience according to any definite rule.

The first thing to make clear is that scientists, freely making their own choice of problems and pursuing them in the light of their own personal judgment, are in fact co-operating as members of a closely knit organization.