In this respect it had its influence, when joined to other hints thrown out by philosophers, in supplying the texts on which Helvetius, Beccaria, and Bentham discoursed at greater length and with a clearer application to definite systems. The utilitarian principle Hume afterwards extended and rendered systematic, in pursuance of the views announced in his correspondence with Hutcheson. In connexion with what is called the "selfish system" of morals, he went no farther than to point out that the source of every impulse must have its relation to the individual person on whom that impulse acts. If it be the sordid impulse of the miser, it must be because the man who feels it loves gold; if it be the profuse impulse of the spendthrift, it must be because the individual who spends has a corresponding desire within himself; if it be the charitable impulse of the person who feeds the poor, it must be because that person is under the influence of inducements which incline him rather to do so than not do so. If the principle be applied to a martyr suffering for conscience sake, or to a soldier who prefers death to submission, it is still because the person who acts fulfils impulses acting on himself. But this is a subject from which Hume appears to have shrunk in his subsequent works. He seems to have disliked the character of being connected with "the selfish school;" and he thus failed to revert to a subject on which his rigid and clear examination would have been a matter of greater interest, than his merely arguing against self-interest being the proper rule of action--an argument that with him amounts to nothing more than a protest against that vulgarization of the system, which charges it with such a doctrine for the purpose of rendering it odious. We shall afterwards find that he had a correspondence on this subject with Helvetius, who wished to bring him over to the admission of his own opinions.