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Article 2739 of comp.ai.philosophy:
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>From: weemba@libra.wistar.upenn.edu (Matthew P Wiener)
Newsgroups: comp.ai.philosophy
Subject: Re: Waking up is hard to do, but somebody's got to do it
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Date: 15 Jan 92 16:28:54 GMT
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In-reply-to: sarima@tdatirv.UUCP (Stanley Friesen)

In article <370@tdatirv.UUCP>, sarima@tdatirv (Stanley Friesen) writes:
>|But your model--preventative maintanance--has been explored and found
>|wanting for decades.

>Hmm, this certainly seems unlikely to me.  Are you sure all approaches to
>testing for PM have been tried?

Of course not.  But the evidence has been at best weak and indirect.
After decades, I would expect better.  Your proposals below are much
better than what's around.

>				  My own body certainly *seems* to recover
>from exertion and stress faster if I sleep than if I do not.

Oh yes, lots of circadian and/or daylight correlations are known.  Yet
sleep deprivation leads to one clear cut result in the short result:
heavy mental confusion.

>Now, I am quite well aware how easy it is for the huma mind to fool itself,
>but these effects seem so strong to me that *some* explanation for them
>is necessary.

I agree.  Sleep could have more than one function.  Or it could have
evolved to have more than one function.  To distinguish these, I ask
the question: why should PM require the turning off of consciousness?

If you say it's a side effect of turning bodily activity off, to allow
PM to proceed, consider the dolphin, which half-sleeps, and does not
get any bodily rest.

>But REM sleep is only a small part of sleep.  It is certainly not the sole
>purpose for sleep.

That is true.  Note that in partial sleep deprivation experiments on mice,
they eventually die if deprived of just REM sleep.

>|Who knows?  Reptiles don't have REM sleep.  Very few mammal species
>|(dolphins, spiny anteaters, ????) don't.

>Dolphins *don't* have REM sleep?  That really plays havoc with sleep as
>a quantum result of brain activity.  Dolphins are the closest thing amoung
>non-human animals to a conscious being.

It would play havoc if we knew more about dolphin sleep, and what their
circadian rhythms were like and so on.  As I pointed out above, the dolphin
plays as much havoc with your view too.

>|I refer to an active self-awareness to get food--tastes good!--rather than 
>|stop the stomach from growling--less filling!

>But, I think that it is very questionable to assume that animals *don't*
>eat because it tastes good (in part).  Certainly my sister's pet dog seems
>to have some very definate ideas about taste, and what she (the dog) likes.

Good grief.  Pet dogs are pampered--they learn to be finicky.  [On a
related note, one study that impressed me is that large parts of our
pain processing is learned.  Dogs raised in utter isolation from even
small injuries have a much higher pain threshhold than your normal dog.]

>This whole thing is a continuum.  [...] How does self-awareness
>differ from a special, advanced version of, anticipation based on
>abstract understanding?  [Hmm, that didn't quite come out right - I
>am trying to suggest that the distinction is a fuzzy, imprecise one,
>rather than a simple Aristotelean binary one].

I'm not in favor of a binary distinction either--I just use binary words.
This goes for both consciousness and depth of sleep.

>|You'll also note that predators like lions generally sleep more than their
>|typical prey like zebras.  They eat their fill and laze around for days at
>|a time.

>Yep, because meat is a much more concentrated source of energy, so less
>is needed.  Thus the zebra *must* spend most of its time eating, while the
>lion simply does not have to do anywhere near as much.  Given a relatively
>safe place to sleep (the middle of a pride with guards posted), one might
>as well sleep when there is nothing else to do.  I certainly tend to.

The above is at best an ad hoc explanation.  You can do this for any
correlation I mention.  My friend Occam likes the unified explanation:
sleep is needed for consciousness/intelligence.

>|>There is a problem here. Almost all Cretaceous mammals were *nocturnal*,
>|>sleeping, if at all, during the *day*, when the dinosaurs *were* active.

>|This is known?  Considering how varied dolphin sleep is from other mammals,
>|or even human from shrew, I find it quite difficult to buy the above based
>|on extrapolation from today's patterns.  Is there some other determination?

>Yes this is known.  It is based on comparative anatomy and taxonomic
>relationships.  Nocturnal animals have identifiable anatomical features
>that show up in fossils (such as large eyes, which are preserved as large
>eye sockets).

My memory of therapsids doesn't include eyes larger than the dinosaurs.
I'll look it up.  Opossums don't have particularly large eyes, although
yes, they are nocturnal and ancient.  (Is there some meaning of "large"
running around that I'm not familiar with?  Could be.  The really large
eyes, like on an owl, are perhaps there for seeing prey from a distance.)

>	        Also it is possible to derive an evolutionary tree of the
>vaious groups of mammals, and they generally trace back to nocturnal ancestral
>forms.

This is the part I'm suspicious of: sleep has evolved to some pretty weird
patterns that I don't like continuity of sleep style assumptions.  That
sleep will be there in some form or other I believe, but it will adapt
to the niche the animal finds itself in.

Anyway, I'm willing to stand completely corrected here, and reply again:

>|>There is a problem here. Almost all Cretaceous mammals were *nocturnal*,
>|>sleeping, if at all, during the *day*, when the dinosaurs *were* active.

Are you implying early mammals did not sleep?  Because of the incredible
dangers of predatory dinosaurs?

I think it's pretty clear that the dangers are there, but they are just
not that overwhelming to the species.  Prey does not feed that often, and
has a smaller population, than predator.  Volta-Lotkera and all that.

>|Are you implying that mammals did not need preventative maintence 1e8 years BP?
>
>No.  But sleep does not fossilize, so we do *not* know if they slept in any
>direct way.  I tend to assume they did, since all living mammals do, but that
>is only a reasonable conclusion, not a fact.  Of course, I do find it hard to
>imagine what a nocturnal animal would be doing during the day if not sleeping!

I too.  Which is why I think your view of the danger aspect is exaggerated.

>						 (Of course the carnivorous
>dinosaurs that were even more closely related to birds *were* rather
>intelligent - the most intelligent forms almost reaching avian levels of
>intelligence, but certainly not mammliam levels).

And these were the ones that early mammals had to avoid.  The ones that I'm
presuming did the most sleeping/estivation then.

>|>					     It is almost as if any level of
>|>processing above that of reflex requires some form of sleep.

>|Yes!  Take out the "almost as if" and you've got what I've been arguing
>|for all along.

>This seems to be almost to trivialize your hypothesis.

It's nothing more than taking the question "why we sleep" at its most
obvious.

>						         This is so widespread
>that your 'consciousness' would exist in fish, and perhaps in some insects.
>This seems to be rather an over-extension of the term.  [At least I seem
>to remember you claiming that sleep is related to consciousness].

Put it on a continuum.

>I might accept that a shrew is conscious, but a dogfish?

So give the dogfish an ultralow primitive consciousness.  So low that
calling it conscious--unqualified--is ridiculous.

>>[mice sleep deprivation experiment]

>Perhaps the naked skin was more susceptible to damage?  It is certainly
>more exposed to radiation.  In fact the syndrome you describe sounds
>suspiciously like radiation sickness.

Huh?  Radiation sickness has far more symptoms.  Are you referring to
some lowlevel radiation sickness syndrome that I don't know of?

>It might also be interesting to do a genetic assay of the lesioned
>tissues to see if they might be suffering from high mutation levels.

And to do the experiment twice more: once heavily shielded and once
at high altitude.  If you're right, the former should live longer and
the latter should die sooner.
-- 
-Matthew P Wiener (weemba@libra.wistar.upenn.edu)


