In a message dated 4/17/2004 9:13:29 AM Eastern Daylight Time,
[log in to unmask] writes:

>My question is already posted in the header of this mail: Why does the
>meaning of words change during the centuries, sometimes even radically?

I think two possibilities that sometimes occur are (1) simple
misunderstanding, and (2) a metaphorical use of a word becoming so widespread that it
replaces the literal use.

Recently I read the surprising (to me) claim that, so far as we can tell from
written records, Lewis Carroll was the first person to use "pretend" in its
modern sense of "make believe."  Earlier, it had meant "make a false claim."
Apparently, either Carroll or someone earlier generalized the meaning of
"pretend that X" from "Act as though X is true when it's false (in order to deceive
someone or claim an advantage to which one is not entitled)"  to"act as though
X is true when it's false" without that restriction, so that it could be used
in "Let's pretend we're kings and queens" (as a game, without dishonesty or
intent to deceive).