Physics has long searched for a “theory of everything”—a single framework capable of explaining the forces that govern the universe. Human behaviour, however, appears to resist that kind of simplicity. Some thinkers, however, have argued that human behaviour ultimately needs a unifying explanation. Through Fix the World, formerly the World Transformation Movement, Griffith presents this as a biological explanation capable of unifying a remarkably wide range of observations about human behaviour. The question is whether human behaviour also has a single underlying explanation—or whether it will always require many complementary theories.