Everybody has developed a unique set of memories over the course of their existence. These memories shape our perception of everything we encounter on a daily basis. Thus everything we can perceive with our five senses is subjective.
Mathematics and physical laws that - according to their respective theories - are universal concepts and nothing we directly perceive. We can only perceive to what they lead, their results, and those observations are subjective again.
Well, to be more accurate our perception is pretty much objective until it actually enters our mind. Up until then all colors and pictures are merely reflected photons and different wavelength. Our brain interprets what we see is a pipe and not just reflected light. That's why you might hear the phrase "We see with our brains" from time to time (at least in German, but I'm sure a similar phrase exists in the English language).
TL;DR
Art is subjective, just as anything else that enters our senses and is interpreted by our brains. Theoretical concepts in their purest form are unaffected (tho it doesn't stop a lot of brains from actually imagining a landscape of numbers for example).
Mathematics and physical laws that - according to their respective theories - are universal concepts and nothing we directly perceive. We can only perceive to what they lead, their results, and those observations are subjective again.
Well, to be more accurate our perception is pretty much objective until it actually enters our mind. Up until then all colors and pictures are merely reflected photons and different wavelength. Our brain interprets what we see is a pipe and not just reflected light. That's why you might hear the phrase "We see with our brains" from time to time (at least in German, but I'm sure a similar phrase exists in the English language).
TL;DR
Art is subjective, just as anything else that enters our senses and is interpreted by our brains. Theoretical concepts in their purest form are unaffected (tho it doesn't stop a lot of brains from actually imagining a landscape of numbers for example).