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I wrote my master's thesis on this exact topic back in 1989. The answer IMHO (which is due to Bertrand Russel [1]) is that the correct rendering of "Aunt May b
by lisper 5y ago
I wrote my master's thesis on this exact topic back in 1989. The answer IMHO (which is due to Bertrand Russel [1]) is that the correct rendering of "Aunt May believes that spider man fights crime" is not BELIEVES(AUNT-MAY, FIGHTS-CRIME(SPIDER-MAN)), it is EXISTS(X): BELIEVES(AUNT-MAY, FIGHTS-CRIME(X)) AND BELIEVES(AUNT-MAY, NAME-OF(X, "SPIDER-MAN"))
and then you can also throw in BELIEVES(AUNT-MAY, NOT(NAME-OF(X, "PETER-PARKER"))) if you like.
[1] https://en.wikipedia.org/wiki/Theory_of_descriptions https://en.wikipedia.org/wiki/Theory_of_descriptions
- gjm11 5y agoI think this is wrong, because it can happen that Aunt May believes "Spider-Man fights crime" (she's read lots of newspaper articles saying so) without there being any specific entity that she believes to be Spider-Man. That is, these two things are different: EXISTS(X): BELIEVES(AUNT-MAY, FIGHTS-CRIME(X)) AND BELIEVES(AUNT-MAY, NAME-OF(X, "SPIDER-MAN")) and BELIEVES(AUNT-MAY, EXISTS(X): FIGHTS-CRIME(X) AND NAME-OF(X, "SPIDER-MAN")), and the second seems to me like a better translation of "Aunt May believes that Spider-Man fights crime", at least for some of the states of affairs you might summarize with that sentence.
- lisper 5y agoYou are exactly right. The natural language version is ambiguous. c.f.: "Aunt May believes that Santa Claus fights crime." Philosophers actually argue about things like this, not so much for Santa Claus fighting crime, but whether e.g. "Santa Claus has a beard" is true or false.