Explain SMBC — the wiki for Saturday Morning Breakfast Cereal

This comic shows a history test question asking the student to "cite two causes of the first world war." The handwritten answers are: "1) The universal wavefunction" and "2) The boundary conditions of the universe." The caption below reads, "Physicists are no longer allowed in history class."

The humor comes from the fact that these answers are, from a certain reductionist physics perspective, technically correct. If the universe is governed by a universal wavefunction and its initial boundary conditions, then everything that happens -- including World War I -- is ultimately a consequence of those two things. The joke satirizes the tendency of physicists to reduce all phenomena to fundamental physics, ignoring the useful explanatory frameworks of other disciplines like history. It is a playful jab at reductionism taken to its absurd logical extreme, where the "causes" of a war become indistinguishable from the causes of literally everything else.