David Hume on moral sentiments

“Morality is nothing in the abstract nature of things, but is entirely relative to the sentiment or mental taste of each particular being, in the same manner as the distinctions of sweet and bitter, hot and cold, arise from the particular feeling of each sense or organ. Moral perceptions therefore, ought not to be class'd with the operations of the understanding, but with the tastes or sentiments.” 

– David Hume, An enquiry concerning the principles of morals (1748)