This is the next Economic Policy enhancing Adjacency bonuses, this time for the Theater Square. However, we can easily say that getting Adjacency bonuses for this district is most problematic of all districts - only Wonders provide a Standard bonus, while other nearby districts provide the usual Minor bonus. So, your Theater Squares will have little or no bonuses, unless you manage to surround them with other districts, and/or build lots of Wonders.
In light of this, Aesthetics becomes almost useless, since another Policy - Meritocracy can provide potentially an equal, or much better Culture bonus. The only case in which you will be able to make good use of Aesthetics, is if you build many Wonders, and manage to arrange them in respect to your Theater Squares in such a way as for them to have Adjacency bonuses of more than 2.
Civilopedia Entry Edit
Aesthetics, focused on the nature of art and good taste, was a product of early philosophers concerned with the creation and appreciation of beauty (forget that foolishness about “eye of the beholder”). By the late Middle Ages, aesthetics had evolved to the point where it did not encompass the functionality or utility of a thing, but rather only its beauty of form, color, contrast, and other aspects. Hence, those soaring Gothic cathedrals. Just before the Renaissance got rolling – and all sorts of folks got involved in judging aesthetic appeal – Medieval thinkers were already developing general theories on proportion, perspective, and harmony for all the arts.