>> Axiom 3. The system should be hierarchical e.g. get the commonest
>> changes to form a kind of a skeleton and add the more exotic ones on
>> top of these. This is not much more than an approximation scheme
>> is already in use in linguistics (as well as in many branches of
> Is this an axiom or a principle for organising our knowledge?
More generally, how does one axiomatise an empirical science? You can't
tell the universe how it _must_ behave. An axiom is _stipulated_ to be
true and is not supposed to be negotiable or falsifiable, which is fine
in maths but not in a discipline where we first observe and then try to
generalise from our observations. Some of these "axioms" are in fact
such generalisations -- not necessarily adequate: for example, "Axiom 0"
is probably true but its formulation is (conveniently?) vague, whereas
"Axiom 1" is not _generally_ true. On the other hand, "Axioms" 3 & 4 are
methodological postulates, not statements about language change.