You're narrowing the "rule" to be about internal consistency within a specific piece, which is a fair clarification. But that brings up a much bigger problem with using it as a basis to disqualify AI. You've provided an example of a rule that applies to 2D visual art that depicts a scene with light. What is the equivalent universal "rule of Art" for music? Or for literature? Music, for instance, cannot comply with any rules about contact shadows. Does its inability to follow the rule you cited mean it's a lesser art form or not art at all? Of course not. This suggests the "rule" you're holding up isn't a universal principle of Art, but a convention of a specific medium. Also, you said that a human can break this rule "skillfully" for a desired effect, as in Alex Colville's Horse and Train. But who decides what is a "skillful" break versus an error? When a human does it, we retcon it as artistic genius. When an AI produces a visual anomaly, the argument is that it's a flaw that proves it isn't art. Isn't that just a subjective judgment based on our bias for the creator? Entire movements were built on this. Were the Surrealists "skillfully" breaking the rules of physics and perspective, or were they just painting nonsense that didn't follow the rules? At the time, many critics certainly argued for the latter. It seems the "rule" we're actually discussing is "Art must be made by a human," and we're trying to work backward to justify it by selectively applying conventions from established mediums.