What Cheerskep says below is complicated by the loose understandings there are of "art criticism". Art history scholars do not say that they are doing art criticism because while they may explain works of art, they only explain the formal and cultural attributes and auras, insofar as they can be agreeably defined, seeking objectivity and almost never subjectivity. Art Criticism examines the work of art, sometimes in isolation and thus with a focus on how it is experienced by the person doing the criticism. In our day of mass media, it's often impossible to distinguish art criticism from art journalism and I don't know how to separate the two endeavors except that journalism would seem to have the lessor obligation, one that simply asserts the existence of some art object. There's another category we know as art appreciation which is a blend of art history and art criticism, with most emphasis on individual audience response.
Actually, I think it's extremely difficult to say why a work of art does not work, far more difficult that the opposite. The good artwork is very likely already invested with much approbation, appreciation, cultural and art historical indexing that one may rely on with confidence but the possibly bad work leads one to judge it by subjective, unexamined opinion that strives only suggests its validity by implying the validity of something outside of the work itself. And these outside implications are unconstrained and are themselves purely subjective. Thus it's difficult to say precisely what physical attributes of the art work, makes it bad. My position is that we can never say precisely what makes a work of art good or bad without recourse to some artificially adopted standards some of them having historical approbation and some of them personal and subjective, existing by authority alone. History proves me right in this because we know that new art, often lacking the echo of that a-priori approbation, is most frequently deemed bad at least until its links to previous art, or other ratifying subject, is teased out and elaborated by artists, critics, and audiences. Many artists try to make bad art for that very reason, not only to subvert their own preconceptions and influences but to avoid them as substitutions for the authenticity of the new work as something new, a new direction, etc. Other do it because they're charlatans who can only make genuinely bad art. I recently saw a group of paintings (all estate gifts) to be deaccessioned by a small museum. Most were bad because, say I, they were clumsy, amateurish redundancies that evoked only embarrassment. Yet a few of them, also incompetently painted, redundant, corny, were nevertheless also quite powerful their effect on me. In other words I was forced to construct a subtle, engaging, and visceral content for them. Were these bad paintings? Yes. Were these good paintings? Again, yes. I am still perplexed by this experience. wc "Art criticism" has for a very long time now been devoted to "explaining" "art", which, claim I, means it seeks to explain why some WoA's result in a.e.'s and others don't. I say the following without having thought it all the way through: Art criticism can sometimes persuasively convey why a WoA does NOT work, but it never tells us why it DOES work (despite veiled tautologies like "It positively stimulates our emotions/neurons/DNA/etc").
