A Failue of Imagination

[From Bruce Gregory (980304.1530)]

It is difficult for me to imagine a network of physicists
debating about who among them really understood Newtonian
physics or the causal nature of action at a distance.
(Philosophers are another story.) You can tell whether someone
understands Newtonian physics by the way they solve problems. If
they get the right answers, nobody cares about whether they have
the correct conception of that Newton's laws "really mean".

Of course it is possible that only a few people on CSGNet can
actuallly apply the theory to predict the outcome of
experiments. If this is so, it is a lot easier to understand the
fact that the precise meaning of terms and the nature of
causal connections is often subject to microscopic analysis.

As for Bruce Abbott, I find him a bit of a pain in the ass. And
a smug one at that. Maybe we should have a vote to see which
of us goes and which of us stays. I'd be happy to abide by the
outcome.

Perhaps we need two networks. One for those of us who are trying
to learn something and one for those who already know it all.

Bruce

[From Bill Powers (980304.1730 MST)]

Bruce Gregory (980304.1530)--

It is difficult for me to imagine a network of physicists
debating about who among them really understood Newtonian
physics or the causal nature of action at a distance.

Try, however, imagining a networks of chemists and alchemists, and how
their debate might look.

Best,

Bill P.

[From Oded Maler (980305)

Bruce Gregory (980304.1530)]

Perhaps we need two networks. One for those of us who are trying
to learn something and one for those who already know it all.

On which of them will you find yourself?

···

-------------------------------------------------
Bruce Nevin (980304.0916)]

Oded Maler (980304)--

I have two "open-loop" functions f1(x) and
f2(x). One of them, when connected in a closed loop will lead to negative
feed-back, the other will lead to a positive feed-back. This was supposed
to be a counter-example to your previous suggestion that it is not useful
to talk about the I/O properties of a function.

It is not a counter-example. It is a departure from the universe of discourse.

The subject here is negative feedback control. If you reverse the sense of
the inputs to a comparator without simultaneously reversing the effect of
error output (at effectors or at reference inputs at a lower level) you no
longer have negative feedback control. I don't know why you want to talk
about positive feedback, which is incompatible with control, but it is not
what we are talking about here.

What I said:

If the function is within a control loop (input function, output function)
how is it useful to talk about its output in S-R terms? Its output is a
contributor to its input, with lag that effectively does not matter for
reasons discussed. R is part of S. S-R analysis is inappropriate even when
talking about a function.

The point is that once a function is part of a negative feedback control
loop linear-causative S-R principles no longer apply to understanding the
inputs and outputs, because the output is part of the input.
----------------------------------------------------

In the spirit of the recent slogan "mathematics, not poetry" :wink:

Claim 1: When a function is part of a feed-back loop [i.e. it's
ouput is fed-back in some way into its input], its form as a function
does not matter.

Counter-example: two functions f1 and f2 such that when you plug one
into itself you get a negative feed-back system, you plug the other in
the *same* way and you get positive feed-back. You can deduce it just by
looking at f1 and f2.

Claim 2: Once a function is part of a *negative* feed-back loop than
the above is true.

Comments: As shown above, being part of a negative feed-back already
depends on the form of the function. Moreover, different functions
lead to different behaviors even if both systems can be classified
as negative feed-back.

The two claims above are from the omniscient analyst point of view.
The next one is weaker:

Claim 3: When a function is part of a feed-back loop, one should
be more careful in interpreting observations of the I/O relations of
the correpsponding system.

This I find acceptable.

--Oded

[From Bruce Gregory (980305.1015 EST)]

Bill Powers (980304.1730 MST)]

Bruce Gregory (980304.1530)--

>It is difficult for me to imagine a network of physicists
>debating about who among them really understood Newtonian
>physics or the causal nature of action at a distance.

Try, however, imagining a networks of chemists and alchemists, and how
their debate might look.

By Jove, I think I've got it!

Bruce

[From Bruce Gregory (980305.1025 EST)]

Oded Maler (980305)

Bruce Gregory (980304.1530)]

> Perhaps we need two networks. One for those of us who are trying
> to learn something and one for those who already know it all.

On which of them will you find yourself?

The former. I trust I'll not be the only one. I'll miss you
though :wink:

Bruce

[From Oded Maler (980305-b)]

Bruce Gregory (980305.1025 EST)]

Oded Maler (980305)

> Bruce Gregory (980304.1530)]
>
> > Perhaps we need two networks. One for those of us who are trying
> > to learn something and one for those who already know it all.
>
> On which of them will you find yourself?

The former. I trust I'll not be the only one. I'll miss you
though :wink:

I knew :wink:

--Oded

i.kurtzer (980305.1400)

[From Oded Maler (980305-b)]

Bruce Gregory (980305.1025 EST)]
Oded Maler (980305)
Bruce Gregory (980304.1530)]

B:
  Perhaps we need two networks. One for those of us who are trying
  to learn something and one for those who already know it all.

O:
  On which of them will you find yourself?

B: The former. I trust I'll not be the only one. I'll miss you
  though :wink:

O: I knew :wink:

me, Isaac, i: this thread ranks as the stinkiest pile of crap yet. Will any
more persons just shup the hell up and start doing research? Its seems
relatively simple. Either you are convinced by the demos, or you are not.
How this translated to fence/net/"get it" side is whether your research is
based about finding controlled variables. Also, this is not helped by the
ubiquitous :wink: mask. It has transmuted into a sickening, thinly, veiled
viciousness. Just say "fuck off" to them personally off-line if you feel it
necessary. I have and it seems to straighten matters out very well.

i.

[from Bruce Gregory (980305.1526 EST)]

i.kurtzer (980305.1400)

me, Isaac, i: this thread ranks as the stinkiest pile of crap yet.

Flattery will not work. You should know that by by now.

Will any
more persons just shup the hell up and start doing research? Its seems
relatively simple. Either you are convinced by the demos, or you are not.
How this translated to fence/net/"get it" side is whether your research is
based about finding controlled variables. Also, this is not helped by the
ubiquitous :wink: mask. It has transmuted into a sickening, thinly, veiled
viciousness. Just say "fuck off" to them personally off-line if you feel it
necessary. I have and it seems to straighten matters out very well.

But I've already told you to do that, and you keep coming
back... :wink:

Bruce