If all beauty is a participation in the transcendent Beauty of Almighty God, the Author of beauty, then why is it that, so often, encountering beauty not only fails to make us more holy, but actually causes us to turn further away from God? Some people are so scandalized by beauty that they mistrust it entirely, which may contribute to the enduring popularity of Manichaeism.
Of course, encountering goodness and truth can also cause a person to sin, but I don't think it's nearly so common to mistrust goodness or truth entirely.
My thought for today is that, though we know beauty when we see it, too many of us don't know what beauty actually is. So our response to beauty is incorrect, and therefore frequently sinful.
What happens, I propose, is this: Beauty is experienced as a pleasurable good, as something that is pleasant to experience, as something that satisfies the appetite. But we often misapprehend a pleasurable good as a useful good, as something that is good because it lets us acquire some further good. We don't always recognize, for instance, that looking at the physical beauty of another person ought to suffice; the pleasure of apprehending a beautiful human body is itself the good we are apprehending, not the opportunity to use the beauty of the body to obtain some other, carnal good.
This idea is at least consistent with the fact that so many people find the beauty of nature conducive to contemplation in a way the beauty of other people is not. In general, the sight of a green tree against a blue sky is not perceived as the means to some other good. (I saw a science fiction program on TV once, set in a future dystopia, in which someone was trying to get rich by selling trees to people who had never seen one; when asked what good trees were, he would say, "They make a nice sound when the wind blow through them.")
So perhaps we need to educate ourselves and each other about what beauty is, what it isn't, and how we ought to respond to it.