Aesthetics (also spelled esthetics) is a branch of philosophy called value theory or axiology, which is the study of sensory or sensori-emotional values, sometimes called judgments of sentiment or taste. Aesthetics is closely associated with the philosophy of art.
What is an aesthetic judgment?
Many see natural beauty folded within petals of a rose. Judgments of aesthetic value clearly rely on our ability to discriminate at a sensory level. Aesthetics examines what makes something beautiful, sublime, disgusting, fun, cute, silly, entertaining, pretentious, discordant, harmonious, boring, humorous, or tragic. A wine-drinker with an unrefined palate may miss much of the subtlety of a fine vintage.
Aesthetic judgments usually go beyond sensory discrimination. For David Hume, delicacy of taste is not merely "the ability to detect all the ingredients in a composition" but also our sensitivity "to pains as well as pleasures, which escape the rest of mankind." Thus, the sensory discrimination is linked to capacity to pleasure. For Immanuel Kant "enjoyment" is the result when pleasure arises from sensation, but judging something to be "beautiful" has a third requirement: sensation must give rise to pleasure by engaging our capacities of reflective contemplation. Judgments of beauty are sensory, emotional, and intellectual all at once.