Up to three kinds of good can be involved in a beautiful object:
- The intrinsic value of the beauty.
- The intrinsic value of the production of something beautiful.
- The aesthetic appreciation and pleasure in those who behold the object.
Now, in the case of something ugly, there is obviously the disvalue of the aesthetic disappreciation and displeasure in the beholders. But I think that is all there is that is bad about the ugly object. And here lies a conceptual asymmetry between the ugly and the beautiful. There is reason to preserve or create a beautiful object even if no one will perceive it; but there is no corresponding reason to destroy or refrain from creating an ugly object when no one will perceive it. If I am to set out to build a wooden telescope, that it would be beautiful is a reason in favor of the production, even if the telescope is only going to be in contact with people in the dark of night and no one will see its beauty. But that it would be ugly is no reason against the production, if no one will see the ugliness. (Maybe the fact that I will see it in my mind's eye might be a reason, but that underscores the analog of (3).) The amount of disvalue in an ugly thing, for a fixed average amount of displeasure and disappreciation, is exactly proportional to the number of beholders, whereas no similar proportionality holds in the case of beauty.
So ugliness is disvaluable in fewer ways than beauty is valuable.
All this may be an aspect of the way evil is but a parasite on the good. Moreover, it may help show an asymmetry between good and evil that is relevant to sceptical theism and the argument from design. The sceptical theist thinks that the evils of the world might contribute to goods beyond our ken. An atheist might reasonable counter that this undercuts any argument from design, because the goods of the world might contribute to evils beyond our ken. However, it may be that the space of possible goods is much more complex than the space of possible evils. For instance, plausibly there can be exceedingly complex aesthetic goods beyond our ken. But can there be exceedingly complex aesthetic evils? Maybe not: all the evil in ugliness, if the above is right, reduces simply to the evils of displeasure and disappreciation, which are in themselves subjective and easily accessible to our minds.