If there is such a person as the average phonologist, he might have a
conception of the relation between phonetics and phonology that comes
close to the relation between social perceptions of crimes and a Code of
Criminal Law. The Code's definition of various types of crimes and the
penalty each type carries ultimately reflect, to put it crudely, the feelings
of the people. Also, the Code's development will reflect social change.
Criminal codes will typically incorporate the changing perceptions of the
general public, and will now begin to include articles devoted to the use
of the Internet, for instance. But at the end of the day, what counts in a
law suit is what is in the Criminal Code, not the feelings of the people. So
it is with phonology. It is easy to show that lexical forms are frequently
related to functional (ergonomic) considerations, and that the way the
grammar processes them into surface representations will amount to a
reasonable articulatory task for the speaker, while equally the acoustic
result will enable the listener to recognise these forms with reasonable
ease. However, ultimately we say things the way we do because our lexical
representations are the way they are, and our phonological grammar is the
way it is.