From its perspective, can't it "see" itself as being at rest while everything else is moving at c? Then, from its perspective it's massless AND not moving, so it doesn't have mass OR momentum and thus has no energy at all. Also, doesn't time stop from the photon's perspective? If an object has no mass, no momentum, no energy and does not experience time, then how can it even be said to exist at all? If it doesn't exist from its own perspective, how can it exist from ours?