The power is not in the choice of metaphor, it is in the ability to shift among metaphors.
Teaching people this other metaphor [...] but not
leaving them with the flexibility to move freely in and
out is not having enabled them at all.
Elsewhere in the
thread
he says the following. I have corrected some typos and
added emphasis.
I expect a firestorm of complaining over the use of the
word `stack’. Maybe I’ll be pleasantly surprised. I
prefer to use such metaphors because I think such
abstractions give people a useful handhold when they are
coming from other backgrounds. I get jumped on a lot
for using a stack metaphor when talking about Scheme
because people apparently think I’ve forgotten that it’s
not a strict stack; personally, I think the people who
are so quick to jump on me have forgotten that even a
metaphor that has a flaw can be a powerful way to
reason and express even when not speaking rigorously.
The remark here is intended to allow someone who is just
barely reading along to confirm that something he may
have strong knowledge of in another domain is in fact
what is being discussed here. To not offer that
handhold seems to me to be impolite.
-- Kent Pitman
Elsewhere in the thread he says the following. I have corrected some typos and added emphasis.