I argue against Kendall Walton's argument against formalism, in his ‘Categories of Art’, that we must always take the history of production into account in ascribing aesthetic properties to works of art. I concede that he is right about representational properties and about what I call ‘contextual’ properties of works of art. But that conclusion cannot be generalized to abstract and non-contextual art, and it cannot be generalized to the non-representational and non-contextual features of representational and contextual works of art. I then dispute Walton's intriguing ‘guernicas’ example. I also consider his other counter-examples. I argue that art-historical categories can be put to one side when we consider the aesthetic nature of abstract and non-contextual abstract works of art. However, there is no doubt that many other works of art possess significant non-formal aesthetic values.