My own commen (partial)
Bach's quote w/r to music applies to visual art as well:
"The aim and final end of all music should be none other than the glory of God and the refreshment of the soul. If heed is not paid to this, it is not true music but a diabolical bawling and twanging."
[Re commenters about the Hellenistic art].. the Greeks and direct descendants were great at working towards the Platonic Ideal (although we haven't seen what their sculpture really looked like when it was tarted up in its original form, and no paintings of Appelles exist AFAIK), and certainly their contribution is huge. The Romans pushed it a bit further (e.g. portrait busts and representational painting). But their philosophy lacked the notion of immanence (their gods were pretty much just major celebrities). Immanence, along with a (too often unobserved) moral law that gave artists the freedom to explore its nature - was brought into the West through Judaism. The search for a deeper understanding of that has been a huge motivator in Western art, and is why its canon is so much more diverse, evolving, and profound than that of other cultures.,