An Enquiry Concerning The Principles Of Morals - pg. 81

In all determinations of morality, this circumstance of public utility is ever principally in view; and wherever disputes arise, either in philosophy or common life, concerning the bounds of duty, the question cannot, by any means, be decided with greater certainty, than by ascertaining, on any side, the true interests of mankind. If any false opinion, embraced from appearances, had been found to prevail; as soon as farther experience and sounder reasoning have given us juster notions of human affairs; we retract our first sentiment, and adjust anew the boundaries of moral good and evil.