till the latter become at last strong and inherent and quasi-instinctive convictions. None the less, if the Imagination did not first suggest the ideas on which the Reason is to operate, we should never obtain anything worth calling knowledge.
We might express all this by saying that Imagination is the mother of working-hypotheses: and this is true of all working-hypotheses, those of the observatory and laboratory as well as those of the nursery. No one who grasps this truth will henceforth deny the debt of science to Imagination. Knowledge is not worth calling knowledge till it is reduced to Law; and Law, as I have shown you above, is a mere idea of the Imagination. I do not deny the subsequent value of Reason; but Imagination must come first. It was from the Imagination that there first flashed upon the mind of Newton the vision of the working-hypothesis by which the apple's fall and the planet's path might be simultaneously explained. Then came in Reason, with experiment, testing, comparing, prepared to detect discrepancies, unlikelihoods, and any want of harmony between the new theory and the old order of things. Finally, the once-no more-than-working-hypothesis, having been found to harmonize with countless past and present phenomena and having enabled us to predict countless future phenomena, is now called a Law, and we are practically certain that it will act. The approval of this Law we owe to Reason, but for the suggestion of it we are indebted to Imagination. On the debt owed to Imagination by Mathematics—the foundation of all science—I will not add anything to what has been said in a recent letter.
Next as to the work of Imagination in art. Poets and artists, as well as astronomers, must be, so to speak, ex analogia Universi; that is to say, they must be in harmony with that order of things which they long to
