Query: why "salt and pepper" but not "pepper and salt"?

[Laurence Horn]

>This evening I received the following query: Why do we always say
>"salt and pepper" and never "pepper and salt?"
>
>    I suppose the answer is that salt is more important.
>  One may have just salt on the table, or both salt and pepper, but
>rarely only pepper.
>
>    Or am I missing something?
>
>Gerald Cohen

I believe it's one of the "freezes" or fixed binomials listed in
Cooper & Ross's "World Order" paper on the topic in the CLS
Functionalism volume (1975).  IIRC, this would indeed involve the
relatively greater importance of salt.  The overall semantic variable
is something they call the "Me First" principle, and presumably we
tend to identify more with salt than with pepper.  (Not me, of
course.)    But the fact you mention in the last sentence is also
relevant--note too the related fact that if I ask someone to pass the
pepper, I'll be likely to get the salt as well, while if I ask for
the salt, it's less likely that I'll get the pepper as an add-on.
(There are also phonological factors in determining the order of
these irreversibilia, as I think we've discussed, but I can't recall
if they would predict "salt and pepper" (1 syllable precedes 2
syllables) or not.

Larry