Despite the idea of “eye of the beholder”, I think it remains true that Beauty is one thing that people have not wholly rejected. People have rejected what is good, and they have rejected what is true, but not yet what is beautiful (for the most part). This is why Fr. Barron and others say that Beauty is the key to evangelization in today’s culture. Present them to beauty; they shall find it good; and lastly, they shall find it true.
Beauty, Goodness, and Truth are interconnected. If that is the case, I agree with the above posters that Beauty must inherently have a essential objectivity to it (in order to be True). I have often held that things that are beautiful correspond to the deliberate order of the cosmos. This manifests itself in musical theory through the rule of 3’s, through the classical understanding of the Heavenly spheres and the institution of the octave, to the Golden Mean in Greek geometry and the perfection of the human form (depiction) in the Renaissance, and so on.
There is a very intimate connection between Beauty and Order. Not colorless order, but order that reveals a things true final cause.
However, I really am fascinated by Mongo’s point: that beauty becomes subjective when it is experienced by a subject. That’s a really intriguing idea. It is not so much that we proclaim subjectivity upon beauty, but that we–in that we are human–perceive beauty through a subjective lens.