This thinker introduced the hypothesis that the world and our memories of the past were created (0[1])five minutes ago. (0[1])The question “who shaves (20[1])the barber?” summarizes a puzzle (0[1])that (20[1])this thinker (20[3])used to illustrate a complication (20[1])of Gottlob Frege’s (20[2])(“FRAY-guhz”) Basic Law (20[1])V (0[1])(“five”). This thinker imagined an undetectable object (20[1])orbiting (20[2])between (20[4])the Earth (20[3])and (20[1])Mars (20[5])in an example intended to shift the burden of proof to theists, (20[2])his namesake (*) “teapot.” This thinker (10[3])discovered that the set containing all sets that are not members of themselves causes a paradox for naïve set theory, leading him to use type theory to explain mathematics in his magnum opus. For 10 points, what author of Why I Am Not a Christian (10[1])collaborated (10[2])with Alfred Whitehead on Principia (10[1])Mathematica? (10[1])■END■