75. Godelian Ghosts

Godel's incompleteness theorem states that for any axiomatic system that is consistent, there are true propositions about the natural numbers described thereby, that cannot be proven from the axioms, but are, nonetheless, true.  Godel's ideas were never meant to be perverted and disfigured by a comic artist: oh well.

Solipsism is a skeptical hypothesis that basically states that anything outside one's own mind is unjustified and may not exist at all.