Growing up, the siblings would often leave the last cookie, piece of cake, etc., not eaten (which annoyed mom).
So, if we were asked "
Did you eat all of the cookies?" we could say, "
No, I did not have one of them". If pressed, we could point to the "
one" cookie that we did
not have.
There are two general forms of the "
one cookie rule" where the
exceptions are important.
"not one cookie ..." (negative statement)
"one cookie ..." (positive statement)
In general, this is called an "
equivocation" in that it could deceive the listener. Equivocations can be used to hide double meanings as in a code or secret code.
Equivocations can be used as jokes which some people like and some do not.