Because not very many of you are philosophers, I have to explain a few pre-requisites. Admit it, you're not a philosopher (most of you). I said it too, "Philosophy... what the fsck would I do with that?"
Anyway, there are really five main branches of philosophy:
1. Epistemology (How you know what you know)
2. Metaphysics (Why things are the way they are)
3. Politics (How you should relate to others)
4. Ethics (What your values are)
5. Aesthetics (Validation of your point of view)

The flow chart is sort of odd, but here it is:
Epistemology\ /Politics
>Ethics <
Metaphysics / \Aesthetics

This is a large topic that I should say at the outset could fill volumes. As a stand-up philosopher, that's easy to say, and seeing the vast philosophical treatises that are out there, it shouldn't be surprising.
This is going to boil down to carbon remains what is actually a large and sumptuous meal.
Art is, as Ayn Rand puts it, a concritization of the artists view of reality. For example, think about the statue of Adonis, compared to the statue of some poor wretch in the middle ages. The Greeks saw humanity as beautiful, powerful, and all the rest of that jazz. The medieval sculptors saw the same humanity, looked at the same types of people (warriors, peasants, kings) and chose to represent humanity as a pitiful being in constant suffering.
What would you think if an artist included something like a zit on the cheek of some gorgeous, buxom vision of femininity? If the artist saw fit to include a detail that, in reality might very well be there, but it's not a the level of importance to include for someone who views people as beautiful, honorable and all the rest.
What you, as artists, writers, sculptors and all the rest put forth in your art, whether you explicitly say it or not, is your view of how reality is. Everything about your style say something about your view of the way things are, and the way they ought to be.
This is why I am so selective about the artists that I choose to watch and look at. Do all women have long, toned legs, perfect waists, hips and chests? Pretty faces, long lashes, sweet eyes, expressive mouths, ect? Are all men muscular, powerful, independent, and so on and so forth? No. But that's the way that it SHOULD be, and could be.
Every time someone looks at a picture that was drawn, they are looking at reality, through the filter of the artist's mind. This is very powerful, because it either provides a subconscious affirmation or rejection of that person's values.