For it exists by virtue of a human impulse and in answer to a human need. To ask a man, in the satisfaction of a metaphysical passion, to forego every other good is to render him fanatical and to shut his eyes daily to the sun in order that he may see better by the star-light. The radical fault of rationalism is not any incidental error committed in its deductions, although such necessarily abound in every human system. Its great original sin is its denial of its own basis and its refusal to occupy its due place in the world, an ignorant fear of being invalidated by its history and dishonoured, as it were, if its ancestry is hinted at. Only bastards should fear that fate, and criticism would indeed be fatal to a bastard philosophy, to one that does not spring from practical reason and has no roots in life. But those products of reason which arise by reflection on fact, and those spontaneous and demonstrable systems of ideas which can be verified in experience, and thus serve to render the facts calculable and articulate, will lose nothing of their lustre by discovering their lineage. So the idea of nature remains true after psychology has analysed its origin, and not only true, but beautiful and beneficent. For unlike many negligible products of speculative fancy it is woven out of recurrent perceptions into a hypothetical cause from which further perceptions can be deduced as they are actually experienced.
Such a mechanism once discovered confirms itself at every breath we draw, and surrounds