[Avery Andrews 921024.1519]
A linguistic thought:
It is a standard tenet of current generative grammar that learners don't
have access to negative evidence. Here's a story about how this may
be wrong.
Suppose that comprehension is effected by a very robust, error-tolerant,
context- & content-= sensitive system. If it fails to find a suitable
meaning for something that gets said, that generates an error-signal
that prompts some reorganization (this is off the main point, & just
included to provide a wider context).
But when the comprehension system does find a reasonable meaning for
an utterance, something else happens: that meaning is sent to the
production system, which in effect returns a list of all the different
ways it might express the same meaning (assuming the perspective of the
original utterer). If the original utterance doesn't come up on this
list, you get a big error signal promoting reorganization of the
production system, but you also get an error signal if there turns
out to be more than one way of producing the meaning. E.g., if the
current production system provides alternatives to what was said.
So if your grammar allows you to say:
John donated the money to the fund.
or:
John donated the fund the money.
to mean the same thing, there will be some error-signal generated each
time the first is used, which can be eliminated by altering the grammar
to exclude the second.
So the non-occurrence of the second (a piece of `negative evidence')
becomes accessible to the learning system. A further prediction is that
the kind of optionality above will be an inherently unstable feature
of languages: if two such forms are used with no discernable difference
in meaning, the language-acquisition systems of the speakers will be
constantly reorganizing without being able to find an error-free
configuration, & presumably at some point one of the forms will other
drop out, or they will acquire subtly different meanings (like the
emergence of magnetic domains in cooling iron, perhaps).
Avery.Andrews@anu.edu.au