Suppose I am trying to understand what some other person believes. This other person believes something that seems very odd to me, but he/she speaks my language, and appears to speak it competently, and in some respects at least is a rational person.
Is there anything we can say in general about the kind of explanation that might put me in some sympathy with apparently irrational views in such a case? I think there is, and that Bertrand Russell's theory of names will get us to it. Russell said that people often confuse the words we consider "names" with what he called logically proper names, both when we use them and when we hear them.
The classic example is drawn from the Superman mythos. Lois Lane at some point believes:
1) That Clark Kent is not strong
2) That Superman is strong.
Assuming further that I am part of that world, and I know that the reference of the two propositions is the same. So I regard (1) as the logical equivalent of the negation of (2). I'm tempted to believe that Miss Lane, who plainly believes both in (2) and in its negation, is being irrational.
If I don't know that she doesn't know that the reference is the same, then I could of course be confused by hearing her state the belief (1).
This simple example feeds into Bertrand Russell's discussion of "logically proper names." There are apparently only two logically proper names, "this" and "I"! This refers to the speaker's sensation at the moment. Lois is looking at Superman as he stops a speeding locomotive and says to herself, "this guy is strong."
But anything other than "this" and "I" isn't a name, in the "proper" sense of referring to that known by acquaintance. It's an abbreviation for a description, instead. "Clark Kent" is short for "the mild mannered fellow in the desk next to mine at work." "Superman" is short for "the man who stopped the locomotive."
Leaving Metropolis out of it now: are there real-world cases in which I might come to understand how people can believe absurd-seeming things by translating the names they use into descriptions?