Task: Text Categorization
Input (English): This thinker wrote that assertive utterances are distinguished by an assertoric force. In the same essay, he claimed that the question of truth pertains only to thoughts, which belong to a third realm besides the realm of matter and ideas. This thinker argued that words only have meaning in the context of a proposition. He introduced the axiom that the value-ranges of two functions are identical if and only if for any object, they map it to the same value. This philosopher explained the difference between identity statements of the form a=a and a=b in "On Sense and Reference." He also showed that Hume's principle could be used to derive all five Peano axioms. Bertrand Russell showed that this philosopher's "Basic Law V" leads to Russell's Paradox. For 10 points, name this German logician who wrote Begriffsschrift and The Foundations of Arithmetic.
Output (English): Social Science