This thinker formalized a statement of equinumerosity that George Boolos later identified as Hume’s principle. This thinker wrote two essays criticizing David Hilbert’s lecture on geometry for relying on the demonstration of consistency. This thinker introduced the turnstile symbol to logic in a book that criticizes Kant’s claim that 2 + 3 = 5 (-5[1])was unprovable. Michael Dummett attributes the beginning of the linguistic turn to this thinker’s use of the context principle while discussing the origin of numbers. This thinker’s (-5[1])Basic Law V (“five”) was shown to be flawed (10[1])when considering sets through Russell’s paradox. A (10[1])puzzle at the start of a paper by this thinker notes “Hesperus (10[1])is Hesperus. Hesperus is Phosphorus.” For 10 points, name this German philosopher who wrote The Foundations of Arithmetic and On Sense and Reference. (10[1])■END■ (0[5])