David Lewis’s General Semantics claims the phrase “green ideas” has the “null” form of this property, which he defines as a function from indices to truth values, sets, or things in the world. For 10 points each:
[10m] Give this word whose adjectival form refers to logics or contexts that are primarily concerned with the meaning of words, rather than the objects they refer to.
ANSWER: intension [accept intensional logic; accept intensional contexts; accept null intension; reject “intention”] (Intension is the opposite of extension.)
[10h] An intension described by this adjective is a function that maps from contexts to characters, which themselves map possible worlds to extensions. Those intensions are used to analyze the meaning of indexicals like “you” and “I” in a semantic theory named for this adjective and developed by David Kaplan.
ANSWER: two-dimensional [or 2D; accept two-dimensional intension; accept two-dimensional semantics]
[10e] Rudolf Carnap based his intensional semantics on the possible world semantics of this philosopher who argued that private languages cannot exist.
ANSWER: Ludwig Wittgenstein
<MB, Philosophy>