Objective beauty does not mean independence from the beholder
I often see the claim that modernism is to blame for the decline in standards of beauty over time. This presupposes two things:
Modernism is inherently ugly.
There exists a concept of beauty such that a) it's an objective property of everything in reality (for an object to be beautiful or not is equivalent to knowing if an object is red or not), and b) whether something is beautiful or not is independent of the observer.
On point 1), I disagree. City skylines are some of the most beautiful phenomena mankind ever built. Works in Progress argues that a decline in beauty leads to less houses or other developments being built, yet consider that a decline in beauty could also be caused by excess government restriction on building. Point 1) fails to demonstrate an exogenous shock.
I am more sympathetic to point 2), given my previous arguments that beauty can be considered a Platonic form. However, this post also explicitly invokes the fact that beauty is compatible with multiple perspectives. This implies that beauty may well be in the eye of the beholder.
For instance, what if different beholders perceive different symmetries, displays of craftmanship, or other signals of order in different dimensions? The same object would them be compatible with numerous distinct representations of beauty. Atonal music is a case in point. The pattern does not arise in tone, but instead in volume or instruments played, and so on.
Whilst objective beauty certainly exists, it is such an elusively defined concept that we cannot construct reliable and robust theories or empirical measurements based on this. Our interpretation is context-dependent, and so indeed in the eye of the beholder.