The possibility of an argument for the existence of God from beauty is compelling, but problematic. (The argument would run something like this: Beauty exists outside of ourselves and, much like rational appeals to goodness and moral absolutes, stands as a signpost to point us towards a Creator of beauty.)
The standard arguments for the existence of God have their base in reason and logic, giving them firm ground, but only appeal to the head, not the heart, crying out for an argument for God from beauty. But an argument from beauty is by its nature based on subjective claims. And the very definition of ‘beauty’ has been under contention at least since modernism; the very notion of whether there can be such a thing that is called ‘beauty’, or what the measure may be to describe something as ‘beautiful’ has also been called into question. So we are potentially in a situation where we wish to make an argument for the existence of God based on something that people cannot agree upon a definition of and which only exists subjectively, if at all.
But if it is possible, an argument from beauty has in its favour a greater historical testimony; rational arguments in some sense might be dismissed as necessities belonging to a post-Enlightenment worldview, based on false dualisms that arose since that time (divorcing spiritual things from material, heaven from earth, etc.); dualisms that didn’t belong even in the world of, for example, J.S. Bach, a study of whose music can reveal a beautiful fusion of the ‘science’ and ‘art’ of music in revealing the glory of God. While rational arguments are in some sense limited to positing finite logical claims, appeals to beauty in art and nature can reawaken the thinker’s sense of wonder, broadening their conceptual horizons and drawing them back into a world of mystery – a world in which ancient thinkers and prophets, and even Renaissance artists, dwelt continually, in attempting to explore and understand the divine.
People who struggle with the logical arguments nevertheless have their breath taken away in the concert hall or art gallery, and testify to the sensation that there is something ‘beyond’ to account for this sense of wonder. Even those convinced of the rational arguments may point to a beautiful sunset as the ultimate affirmation of their beliefs – ‘how can you see that and not believe in God?’
A proper argument for beauty needs to be able to engage with the rational problems (the subjectivity of beauty) but also move beyond them in order to engage most fully with the historical breadth of encounters with beauty in creation and art. For a starting point I would cite the work of Jeremy Begbie, who has been lurking in the background the whole time I’ve been writing; but honestly I’m not well enough read yet, and have only read his Peculiar Orthodoxy; let alone having read other theologians on these issues. This is something my brain will keep cooking on for a while.