I find rock art very interesting and see it as a somewhat distant ancestor to written languages. As for the first theory we talk about, making art for the sake of art, I think it is less likely than some of the others. At 35 kya, hominin had to use much more time than current populations to process food and build structures. Setting aside cognitive abilities for now, it seems as though there would little surplus resources and time to devote to art for art’s sake. I think it is far more likely that there is some meaning behind it, whatever that may be.
There is probably no single theory that could sum up all of the different depictions found among early rock art. Maybe one group used them to mark a meeting spot while another used them in youth initiations. Who’s to say one idea is correct over another, especially considering the diversity behind modern art forms? I tend to think that the rock art is a consequence of gatherings. Maybe they happen as an initiation, as a tool to explain some conquest, as a display of skill, or even as a result of free time.
The mysticism aspects have less appeal for me because of the intangible, abstract ideas behind it. There is one level of cognitive ability that allows someone to see something and then create a representation of that thing. Adding complex abstract meanings behind that representation is another level. I am still not convinced that these hominin were thinking in that manner yet.
Comparing the early rock art to something like that of da Vinci is not possible. Each great artist is known for distinct styles and representations. Cezanne was about colors and impressions, da Vinci was about realistic and detailed works, Picasso is abstract and into cubism. The first expressions of art are going to be basic, getting outlines, shapes, figures, and colors on the medium. That is probably what the people were looking at. Less developed cognitive ability probably contributes to this difference, but how the artist sees the world contributes more. “This dark figure in the distance looks rounder than another dark animal that I need to protect myself from. I’ll draw myself based on my shadow.” From my experience, when you change what you are focusing on, the art created also changes. Does the artisan look at shadows, color, shape, meaning, motion, technique?