Originally Posted by JasonGillespie
When we look back to the earliest cave paintings and stone carvings we see an abstraction of reality.
In other contexts 'an abstraction of reality' can mean something else. Perhaps what you mean is that these are artistic interpretations of human figures and animal figures. And they have been good enough, they served the purpose, as long as other people can understand what they are supposed to depict - man, woman, animal, etc.
It is of course the ancient Greeks who were the first people to go for realism in figurative sculptures.
Abstract art went on to include our artistic interpretations of other things we see, say rocks, trees, etc. Going further, it is broadened to include art with no connections with any real tangible things.