From: jbates@encore.com (John W. Bates)
Subject: Re: Spoken Like a True ProLifer
Organization: Encore Computer Corporation
Date: Wed, 13 Jan 1993 02:16:15 GMT
	<1993Jan12.214229.9246@organpipe.uug.arizona.edu>


In article <1993Jan12.214229.9246@organpipe.uug.arizona.edu> 
sfm@manduca.neurobio.arizona.edu (Stephen Matheson) writes:
>From article <JBATES.93Jan12132814@pinocchio.encore.com>,
>by jbates@encore.com (John W. Bates):
>> In article <1993Jan12.040001.6011@mnemosyne.cs.du.edu>
>> mcochran@nyx.cs.du.edu (Mark A. Cochran) writes:

>> This is true. The question is, just how "tuned" are our thought processes?
>> How much do they depend upon internal synchronization? I don't believe
>> that the answer to that is known. Certainly processes exist in less
>> complex systems which do require a great degree of synchronization:
>> take, for example, the escape reflex of a squid. How comparable that
>> is to human thought, I couldn't tell you.
>
>You must not be a behaviorist.

Ghods, no. Stimulus-response is useful, but certainly not all-encompassing.

>> Pardon me for butting in here, but I have a small amount of relevant 
>> experience, and this is a fascinating conversation.
>
>Oh, you're more than welcome.  In my response to Mark's post, I
>thrashed about as best I could to make the point you make so
>effortlessly below.  I wish I'd known you were coming; I might
>have been able to hide my ignorance a little longer :-)...
>
>> Redundancy in the brain is not the same as redundancy in a computer,
>> or even in most human engineered systems. Whereas humans tend to build
>> redundancy in by having multiple copies or backups, the brain's 
>> reduncancy comes about as a result of its distributed nature. A great
>> deal of signal error or loss can be endured before the output, such as 
>> it is, is significantly affected. Losing signal might be equivalent to
>> say, losing a pixel from each letter in this post. 

Aww, shucks. Now you've made me blush. Still, with an entirely unmyelinated
nervous system, signal loss might prove to be significant. I would consider
higher-level thought processes to be extremely impaired, if they existed
at all. Which raises the question, what is the relevance, or even the
definition, of higher-level processes in a fetus? 

[deletions, basically assuming lack of complex brain function, given
 impairment of less complex functions]

>> I consider that a reasonable assumption.
>
>Reasonable enough to guide your own moral decisions?

My moral decision to support the choice of abortion has little to do
with personhood. However, if I assume that I had no other reason, I would
consider it reasonable enough to have absolutely no qualms about abortion
prior to the fourteenth week; very few about abortions prior to the onset
of myelination; and *maybe*, just *maybe*, be opposed to abortions before
viability. So, yes, I do think it's reasonable enough to assume that
more complex functions are based upon less complex functions. (note: there
are a host of implicit assumptions in that last sentence, which I consider
reasonable to make, but unreasonable to list.)

[deletions]

>Well, to me the issue is whether a given definition of personhood
>is useful and/or widely accepted, and whether it leads to unacceptable
>consequences.  Exclusion of neonates is, to me, an unacceptable
>consequence, and IMO renders the definition useless.  If a certain
>definition of personhood based on a certain definition of consciousness
>resulted in the approximate onset of personhood being estimated to 
>be age 8, I think most people would reject the definition as being
>at least useless, if not downright scary.
>
>I have argued, as you have, that science itself does not form the
>basis for moral judgments or philosophical definitions, but provides
>information for the application of those judgments or definitions.

I think that we are arguing differing views of usefulness. I would regard
the best definition of personhood to be one that is most useful in
analysis of cognition. You seem to be talking about the definition most
useful to society. So what am I doing? I'm waving my hands in the air.

The thing is, just because neonates would not be considered persons does
not imply that infanticide is justifiable. It is entirely possible, and
in fact common, to protect with the force of law things which are not
necessarily persons or the property of persons. I would hold that as
developing humans, neonates are worthy of protection, even if it can
be shown that they do not fit some definition of personhood. 

[deletions]

>>>others do as well. But for it to qualify as some omen of developing
>>>intelligence, it would need to be (to me anyway) organized. 

[deletions]

>> Here's where it gets interesting. I recently saw a paper which was an
>> analysis of the activity in a fetal cat's geniculo-striate pathway and
>> the lateral geniculate nucleus. What was assumed to be random activity
>> now seems not to be, but rather a hard-coded sort of "training exercise."
>> Even when the cat's eyes are closed (and in fact, have not ever been
>> opened) this training is preparing the visual system for eventual use.

My apologies. I had some trouble finding the paper, until I discovered that
it was not a paper, but rather an article published in _Scientific
American_. "The Developing Brain", September 1992. Carla Shatz.

>Whatever the data were, I suspect the above could be little more than
>speculation.  Important developmental events such as synapse formation,
>synapse elimination and cell death are frequently activity-dependent.
>The presence of non-random activity in the developing brain is, IMO,
>extremely noteworthy.  However, to conclude that it is a "training
>exercise" is, I believe, a particularly risky bit of teleology.

That's why I put it in quotes. I speak of training as the development,
via repeated interaction, of a functional network from a more-or-less
random one.

>Another plausible hypothesis is that the patterned activity is provided
>for the specific sculpting of the geniculocortical connections via
>activity-dependent processes (e.g. Hebbian interactions).

What do you regard as the difference between "training" and "sculpting"?
My apologies if I am confusing you with my terminology, but I've often
heard references to training a network. Again, my experience is weak on
neurobiology. I just get by with models of networks. Once you start
talking about ion channels, well, I start spinning. A training exercise,
to me, is a repeated series of inputs intended to remove some of the
randomness from the network.

From the article referenced above:

		"They demonstrated directly that retinal ganglion cells can 
		indeed spontaneously generate busts of action potentials in
		the darkness of the developing eye... All cells on the array
		fired within about five seconds of one another, in a 
		predictable and rhythmic pattern... Even more remarkable, the
		spatial pattern of firing resembled a wave of activity that
		swept across the retina at about 100 microns per second... We
		found that these spontaneously generated retinal waves are
		present throughout the period when eye-specific layers take
		shape. They disappear just before the onset of visual function."
			- description from neonatal ferret retina study.
			
		"Is the retina a special case, or might many regons of the
		nervous system generate their own enogenous activity patterns
		early in development? Preliminary studies by Michael O'Donovan
		suggest that the activity of motor neurons in the spinal cord
		may also be highly correlated very early in development... Like
		those in the visual system, the signals would refine the 
		intially diffuse connections within targets."

The conclusion is also worth reading, but somewhat tangential and long
to include in this post. I'll mail it to you if you want.

>> Which raises the question: is the activity in a fetus' brain, which 
>> might be mistaken for random thought processes, actually a training
>> exercise for eventual thought and consciousness? If so, when does it
>> cease to be training? I would tend to lean towards the point at which
>> external stimuli begin affecting the patterns. 
>
>Which could easily occur very early in neural development.

Yes. I hadn't thought that through. However, to quote again from that
article: "In higher vertebrates, this process of refinement can occupy
a protracted period. It can begin in utero and, as in the primate
visual system, continue well into neonatal life..." It would appear
that visual training, at least, does not terminate with the addition
of external stimuli. Should have been obvious to me, given the visual
deprivation experiments on neonate primates.

Still, the question remains: if it can be shown that a fetus' brain is
engaged in this synchronized firing, would you regard that fetus as being
thinking? Would that fetus be a person, while its nervous system is
preparing for external stimuli?

>> Unfortunately, I don't have the references for the paper here, and
>> I did not read it thoroughly when I had it. I'll dig it out tonight
>> and see what it says. It's entirely possible that I read too much
>> into their conclusions.

Also noted as a reference, which would probably be more detailed and
conclusive: "Competetive interactions between retinal ganglion cells
during prenatal development." Carla Shatz in _Journal of Neurobiology_
Vol 21, No. 1, pp 197-211; Jan 1990.

>Some, like myself, would be happy if the fetus' personhood were given
>what we consider to be a fair shake.  If "the conflict" mentioned above
>is the potential conflict between the well-being of mother vs. fetus,
>then I agree that the conflict will remain.  I am skeptical that
>there is sufficient conflict between mother and fetus to warrant the
>discarding of the fetus and her/his personhood (whatever it amounts to)
>1.5 million times a year.

But a great majority of those abortions occur before there is *any*
significant brain function. IMO, at least. Perhaps you could categorize
what sort of function you feel a fourteen week old fetus is capable of,
and we could work towards a definition of personhood from there?

>> Can somebody please insult me? Nobody ever insults me... Do I have to
>> insult someone else first? (Actually, I think I insulted Chaney or Hall
>> sometime back, but I didn't get anything back. Oh, and I got Nyikos
>> to post his SAT scores, but he forgot who I was. He did call me a "bozo",
>> but that hardly counts. He didn't even use my name.)
>
>Well, Mark's a recognized expert in the field, but I'd be happy to give
>you my best shot, you hopelessly clueless, wishy-washy, hand-waving,
>synapseless, overmyelinated, randomly distributed network nerd.
>Whew.  Now I need a rest.

Hang on, I've got an insult *and* a threat. Here goes:

	Futue te ipsum et caballum tuum. Catapultam habeo. Nisi pecuniam
	omen mihi dabis, ad caput tuum saxum immane mittam!

Top that!

>Steve Matheson   Program in Neuroscience   University of Arizona

John
Newsgroups: talk.abortion