An Enquiry Concerning The Principles Of Morals - pg. 143

There is a MANNER, a grace, an ease, a genteelness, an I-know-not-what, which some men possess above others, which is very different from external beauty and comeliness, and which, however, catches our affection almost as suddenly and powerfully. And though this manner be chiefly talked of in the passion between the sexes, where the concealed magic is easily explained, yet surely much of it prevails in all our estimation of characters, and forms no inconsiderable part of personal merit. This class of accomplishment, therefore, must be trusted entirely to the blind, but sure testimony of taste and sentiment; and must be considered as a part of ethics, left by nature to baffle all the pride of philosophy, and make her sensible of her narrow boundaries and slender acquisitions.