What is beauty?

Adherence to social consensus + Genetic Fitness = Physical beauty

Social consensus will be things like the current body size preferences, fashion/adornment preferences, and so on. Genetic Fitness is WHR, facial symmetry, and things like that.
So take a genetically fit (‘biologically attractive’) woman, and throw her in any space and time. Provided she can match up to the status quo of that time, she’ll always be a catch. And even if she didn’t match up, she’d probably be seen as attractive to some extent. Likewise, a woman who isn’t as genetically attractive can ‘trade up’ by adhering to the social consensus.
In other words, take Jessica Alba, and fatten her up, or use brass rings to make her neck seem longer, or pluck her hair line back and make her skin pale – and she’d still be considered beautiful in Ghana, Northern Thailand, or Elizabethan England, respectively. Do all three, of course, and she’d be an absolute smash in a goth club.

http://generallythinking.com/what-is-beauty/