An Enquiry Concerning The Principles Of Morals - App: pg. 158

But though reason, when fully assisted, be sufficient to instruct us in the pernicious or useful tendency of qualities and actions; it is not alone sufficient to produce any moral blame or approbation. Utility is only a tendency to a certain end; and were the end totally indifferent to us, we should feel the same indifference towards the means. It is requisite a sentiment should here display itself, in order to five a preference to the useful above the pernicious rendencies. This sentiment can be no other than a feeling for the happiness of mankind, and a resentment of their misery; since these are the different ends, which virtue and vice have a tendency to promote. Here, therefore, reason instructs us in the several tendencies of actions, and humanity makes a distinction in favour of those, which are useful and beneficial.