encountered. Since a babe was born in a manger, it may be doubted whether so great a thing has happened with so little stir.
The thesis which these lectures will illustrate is that this quiet growth of science has practically recoloured our mentality so that modes of thought which in former times were exceptional, are now broadly spread through the educated world. This new colouring of ways of thought had been proceeding slowly for many ages in the European peoples. At last it issued in the rapid development of science; and has thereby strengthened itself by its most obvious application. The new mentality is more important even than the new science and the new technology. It has altered the metaphysical presuppositions and the imaginative contents of our minds; so that now the old stimuli provoke a new response. Perhaps my metaphor of a new colour is too strong. What I mean is just that slightest change of tone which yet makes all the difference. This is exactly illustrated by a sentence from a published letter of that adorable genius, William James. When he was finishing his great treatise on the Principles of Psychology, he wrote to his brother Henry James, ‘I have to forge every sentence in the teeth of irreducible and stubborn facts.’
This new tinge to modern minds is a vehement and passionate interest in the relation of general principles to irreducible and stubborn facts. All the world over and at all times there have been practical men, absorbed in ‘irreducible and stubborn facts’: all the world over and at all times there have been men of philosophic temperament who have been absorbed in the weaving of general principles. It is this union of
