Surely you are arguing different points. Isn't the "mereological
fallacy" a catchy term for the fact that the boundary of "brain" as the
source of behaviour is far blurrier than is typically acknowledged? If
we consider LTP at a given synapse as part of some change made to the
organism by experience, how much of the organism do we need to consider
in order to contextualise the change correctly? Do we consider the
hippocampus? Both hippocampi? The forebrain? The CNS ending at the
dura? The CNS plus whatever PNS elements contributed to the experience?
The receptors? The body part which held the receptors? The entire
organism? There isn't really a sensible point to draw a boundary in
this continuum. However, when we say "the brain is the source of
behaviour" or statements to that effect, it implies a distinction
between what's in the "brain" and what's not, and that the causation is
an action of the first category and not the second.
Since there is no universally defensible "line" to be drawn in the
continuum between a single synapse and the organism-as-a-whole, one
could consider it a "mereological fallacy" (mereological with a small
"m", if you like, meaning "concerned with the relationship between parts
and wholes of things", rather than the formal systems dealing with
part-whole relationships) to pretend that there was a discrete "part" of
the organism which caused the behaviour.
Thus we could say that things "in the brain" could be critical in
producing behaviour as observed, but simultaneously acknowledge that
it's erroneous to pretend that this "brain" is a distinct part of the
organism, and has a behaviour which is distinguishable from the
behaviour of the organism as a whole.
To me this suggests that the views of Mat and Glen can be simultaneously
true without conflict, since one addresses the notion of where behaviour
is triggered, and the other is concerned with not pretending that this
is somehow separate from what the organism does as a whole.
Now I expect you will both attack me instead! Still, I'd like to know
your reactions and whether this is a reasonable paraphrase of your views.