What is beauty

The concept of beauty and related concepts are difficult if not impossible to define. I suppose they have some connections with other concepts. For example, all else being equal, if something is beautiful in a certain respect, we tend to enjoy the apprehension or perception of that aspect of beauty. This is an area I haven't really thought much about. I might venture two guesses though. First, a philosophical account of beauty and ugliness (if it is possible to have such an account) should ultimately explain them in terms of the effects and emotions beautiful and ugly things elicit in us. So these qualities are different from for example electricity. We don't define or explain electricity in terms of what electricity does to us. Second, aesthetic values are very different from moral values. I think the case for aesthetic relativism is a lot stronger than the case of moral relativism.
Judgments about beauty and ugliness are notoriously culture-bound. Bell bottom pants were all the rage during my parents' time. They look rather silly to me but now they are making a come back. Yet there can still be some universal general principles at work in our brain that affect our aesthetics judgment. Many studies have suggested that symmetry plays an important role in determining whether someone is beautiful. Young children tends to like music with strong and clear rhythm and beat. Of course, these generalizations might have all sorts of exceptions, and can express in behavior in all kinds of ways depending on the influence of culture and the environment. After all, many people think that Marilyn Monroe would be less beautiful if she were to have a symmetric face without her mole (or to have two for that matter).