"There is an appealing idea about beauty which goes back to Plato and Plotinus, and which became incorporated by various routes into Christian Theological Thinking. According to this idea beauty is an ultimate value - something that we pursue for its own sake, and for the pursuit of which no further reason need to be given. Beauty should therefore be compared to truth and goodness, one member of a trio of ultimate values which justify our rational inclinations. Why believe p? Because it is true. Why want x? Because it is good. Why look at y? Because it is beautiful. In some was, philosophers have argued, those answers are on a par: each brings a state of mind into the ambit of reason, by connecting it to something that it is in our nature, as rational beings, to pursue. Someone who asked 'why believe what is true?' or 'why want what is good?' has failed to understand the nature of reasoning. He doesn't see that, if we are to justify our beliefs and desires at all, then our reasons must be anchored in the true and the good.
Does the same go for beauty? If someone asks me 'why are you interested in x?' is 'because it is beautiful' a final answer - one that is immune to counter-argument, like the answers 'because it is good', and 'because it is true'? To say as much is to overlook the subversive nature of beauty. Someone charmed by a myth mat be tempted to believe it: and in this case beauty is the enemy of truth. (Cf. Pindar: 'Beauty, which gives the myths acceptance, renders the incredible credible', First Olympian Ode.) A man attracted to a woman may be tempted to condone her vices: and in this case beauty is the enemy of goodness (Cf. L'Abbé Prévost, Manon Lescaut, which describes the moral ruin of the Chevalier des Grieux by the beautiful Manon.) Goodness and truth never compete, and the pursuit of the one is always compatible with a proper respect for the other. The pursuit of beauty, however, is far more questionable [...].
The status of beauty as an ultimate values is questionable, in the way that the status of truth and goodness are not. Let us at least say that this particular path to the understanding of beauty is not easily available to a modern thinker. The confidence with which philosophers once trod it is due to an assumption, made explicit already in the Enneads of Plotinus, that truth, beauty and goodness are attributes of the deity, ways in which the divine unity makes itself known to the human soul. That theological vision was edited for Christian use by St Thomas Aquinas, and embedded in the subtle and comprehensive reasoning for which that philosopher is justly famous. But it is not a vision that we can assume, and I propose for the time being to set it to one side, considering the concept of beauty without making any theological claims."
Scruton, Roger. Beauty. New York: Oxford University Press, 2009 (pp2-4).