In any discussion of “beauty” it is important to remember that much of what we mean by that is culturally determined. The current generally-accepted standards for feminine beauty, for example, privilege persons of European ancestry over those whose genetics owe more to, say, Central Asia, or West Africa.
Something similar appears to have taken place in the realm of literature, in that some time ago a group of (white, male, Western) critics decided that in-depth exploration of the human psyche was the only acceptable standard against which literary quality should be judged. This has always seemed daft to me: rather like art critics suddenly deciding that the naturalistic portrait was the only acceptable form of painting. Rubens might have been happy with it, but Dali would have been furious and Turner might have given up in despair. Sooner or later this silliness is going to explode, but it may take another generation or two.
There are things that appear to be admired as beautiful in all human cultures, but as science fiction writers and critics we should immediately be suspicious of potential species-related bias. Nnedi Okorafor was a guest on a BBC World Series program recently, and one of her fellow guests was a woman who designed interiors for hospitals with a view to making them better places for healing. Her explanations for why certain design choices worked were rooted firmly in evolutionary biology. So a set of colours that is restful and calming to us might prove dangerously stressful to the Kzinti.
When someone like Dirac talks about “beauty”, however, something rather different is implied. The qualities he is looking for include universality, simplicity and explanatory power. The laws of physics are, we believe, equally applicable here and on planets in distant galaxies. They can be reduced to very simple mathematical equations. And they often explain all sorts of apparently unrelated phenomena.
Does an equivalent exist in art? The closest thing I can think of is the idea of the Golden Ratio. Because this is firmly rooted in simple mathematics (the Fibonacci series) it is pretty much guaranteed to be universal. An alien from another galaxy will recognize it just as readily as we do, and will probably also find it pleasing.
Whether we can find anything similar in literature is another matter. How much is what we find beautiful in literature culturally determined? There could be some essential rules of plot construction that are somehow related to the basic nature of time, but beyond that I think we increasingly get into discussions that relate to culture. Heck, we are still talking endlessly about whether appreciation of literature is gender-specific.