William James Quote

The necessity of faith as an ingredient in our mental attitude is strongly insisted on by the scientific philosophers of the present day; but by a singularly arbitrary caprice they say that it is only legitimate when used in the interests of one particular proposition, — the proposition, namely, that the course of nature is uniform. That nature will follow tomorrow the same laws that she follows today is, they all admit, a truth which no man can know; but in the interests of cognition as well as of action we must postulate or assume it.

The Sentiment of Rationality (1882)