T 2.3.10.4

But tho' the exercise of genius be the principal source of that satisfaction we receive from the sciences, yet I doubt, if it be alone sufficient to give us any considerable enjoyment. The truth we discover must also be of some importance. 'Tis easy to multiply algebraical problems to infinity, nor is there any end in the discovery of the proportions of conic sections; tho' few mathematicians take any pleasure in these |researches, but turn their thoughts to what is more useful and important. Now the question is, after what manner this utility and importance operate upon us? The difficulty on this head arises from hence, that many philosophers have consum'd their time, have destroy'd their health, and neglected their fortune, in the search of such truths, as they esteem'd important and useful to the world, tho' it appear'd from their whole conduct and behaviour, that they were not endow'd with any share of public spirit, nor had any concern for the interests of mankind. Were they convinc'd, that their discoveries were of no consequence, they wou'd entirely lose all relish for their studies, and that tho' the consequences be entirely indifferent to them; which seems to be a contradiction.