But the Mind Projection Fallacy generalizes as an error. It is in [...] Kant’s declaration that space by its very nature is flat[.]
If anything, Kant committed the opposite of the Mind Projection Fallacy. Rather than assuming that properties of his mind were properties of external reality, he claimed that many properties of external reality were in fact properties of his mind. For him, everyone else was committing the Mind Projection Fallacy by supposing that space was in the territory, when in fact, he argued, space was just part of our map.
If anything, Kant committed the opposite of the Mind Projection Fallacy. Rather than assuming that properties of his mind were properties of external reality, he claimed that many properties of external reality were in fact properties of his mind. For him, everyone else was committing the Mind Projection Fallacy by supposing that space was in the territory, when in fact, he argued, space was just part of our map.