Answer:
Aesthetics.
Explanation:
Aesthetics would be the branch of philosophy that would be able to determine which painter is "better". This philosophy focuses on beauty and taste. It tries to consider what we think, what we feel and focus at in our minds when we face with aesthetic objects, such as paintings. One of the sub-branches of this philosophy is the study of art, which tries to comprehend and study how artists create and perform works of art as well as how one comprehends and feels said art.