[From Bill Powers (970929.1109 MDT)]
Bruce Abbott (970927.0855)--
Don't put words in my mouth. I neither said nor implied that the organism
was "something passive that is simply acted upon by the food pellets." What
I said was that the effects of a variable on other variables in this complex
system depend on the state of the system. As I recall, any physical
determinate system can be defined completely by its variables, their
functions, and an initial state (e.g., at time t0), from whence one computes
all subsequent states at time t1, t2, etc. Or are you now claiming that a
control system is an indeterminate system?
A living control system is, to some extent, actually an indeterminate
system, and it is also, in practical terms, indeterminate. To the extent
that reorganization involves random processes, it is actually
indeterminate. To the extent that its organization is a product of
evolution and its behavior a function of unobserved variables, it is for
all practical purposes indeterminate: it is certainly not determined by the
present state of the world we can observe.
Determinism is a matter of faith, and so is irrelevant in any scientific
discourse. We can observe and infer the states of variables, and discover
relationships among them. But there are always variables of which we know
nothing, and for all we know they are manipulated by a malevolent God. To
say anything at all about them is a waste of breath.
What does matter is to account for phenomena in terms of the variables we
know about or propose to exist. If we can account for 99% of the variance
of the observations using only known variables, then any indeterminate
factors bearing on that phenomena are relatively unimportant. Even if a
malevolent God is varying those other factors, He can't influence the
outcomes of our experiments by more than 1%.
Skinner's philosophical position was basically an argument from
determinism. He made two major mistakes in this argument, and they were
both in the premises. First, he assumed that the _present_ environment,
during the lifetime of an organism, determined behavior. And second, he
assumed that behavior without a prior causal event is impossible (despite
his assumption that initially, operant behavior is simply "emitted"). The
first mistake was simply an oversight, but the second came from ignorance.
If Skinner had known anything about electronic systems, he would have
known that some organizations of matter can produce systematic behavior
patterns spontaneously, simply because of their internal connections and
without any external stimulus driving them.
The concept of "mechanism" is not synonymous with "determinism." Not, that
is, in terms of modern understanding of mechanisms.
And you have left me completely in the dark as to how you feel about these
replies:
...Yes, I know. I am not speaking of linear cause-and-effect. What I mean by
a "purely mechanistic way" is that one can specify a physical mechanism,
involving nothing but ordinary physical interactions, that will behave in
the required way.
You want to talk about the effect of the food pellet on the error signal.
But the appearance of the food pellet is a function of the error signal.
What sets my teeth on edge is mixing the two ways of describing things, so
you treat the food pellets as if they were independent variables. If you
can show some other variable downstream that is a function of food pellet
intake ALONE, then you can speak of this little segment of the system in
those terms; you're only describing one component of the system, which will
always remain the same. But when you start extending the range of the
"effect" so it includes not other other subsystems, but other variables
that are independent of the one you started with (like the reference
signal), this is no longer legitimate.
If you know that y = f(a,b), you can't speak of "the effect" of a on y. You
can speak of the partial derivative of y with repect to a, which assumes
that b is held constant at some known level, but in general that way of
defining an effect of a on y will depend on the level you choose for b. If
your objective is to predict y, knowing a alone is simply insufficient.
I thought satiation occurred exactly when the rate of intake equals the
rate of loss (the rate of loss is assumed proportional to nutrient level).No, it occurs when the system reaches its reference level and thus no
further action occurs. When you've had enough, and don't want no more, you
are satiated. Beyond that point you will take action to _prevent_ more
food from entering your system.
So now you're saying that satiation appears only when the perceptual signal
reaches its reference level. In that case, the effect of the first few
pellets, which reduce the error and cause behavior to decline, does _not_
qualify as an example of satiation, as you said it did the other day. If
you will recall, I said that the control model you're using for comparison
with EAB phenomena will exhibit maximum behavior before the first pellet is
delivered, and that this behavior rate will decline for every subsequent
pellet. Your reply was that this is an example of satiation, not
reinforcement. But in the model, this effect occurs while the controlled
variable is still far from its reference level, so according to what you're
saying now, it is not an example of satiation.
The fact is that the control system will will show maximum behavior before
the first food pellet has been delivered, and that behavior will then
decline with every food pellet delivered/consumed. Doesn't this create some
difficulties in saying that the food pellets are reinforcers?
Best,
Bill P.