From: John Clark (jonkc@worldnet.att.net)
Date: Thu Sep 23 1999 - 10:22:09 MDT
Eliezer S. Yudkowsky <sentience@pobox.com> On September 22, 1999 Wrote:
>The only reason I believe them [Penrose & Hameroff] at
>all, is because quantum coherence is a probable prerequisite for any
>number of ineffabilities, not just the ones they propose.
I don't know exactly what ineffabilities they propose because all that they say
boils down to just "There's magic going on in the microtubules". There is no
way to prove them wrong because they don't tell us what we're supposed to
find, they could shrug off a thousand years of negative results and say
"you just haven't looked hard enough yet". That's not science.
By the way, microtubules aren't limited to neurons, every cell in your body has
them, plants have them too. Are plants conscious? When I slice a tomato is
there a silent scream?
>I'm not sure I credit the stochastic dogma of neural nets. It's such a
>tremendous amount of wasted computational power. It seems to me, on
>purely evolutionary grounds, that every little quaver will be exploited.
Evolution doesn't need to come up with the perfect design, it just has to
be better than the competition. In addition, even if an organic quantum
computer were possible there is no reason to think evolution could get
there from here.
A few of reasons for natures poor design, the most important is the last.
1) Time Lags: Evolution is so slow the animal is adapted to conditions that
no longer exist. that's why moths have an instinct to fly into candle
flames. I have no doubt that if you just give them a million years or so,
evolution will give hedgehogs a better defense than rolling up into a
ball when confronted by their major predator, the automobile. The only
problem is that by then there won't be any automobiles.
2) Historical Constraints: The eye of all vertebrate animals is backwards.
The connective tissue of the retina is on the wrong side so light must
pass through it before it hits the light sensitive cells. There's no doubt
this degrades vision and we'd be better off if the retina was reversed as
it is in squids whose eye evolved independently. It's too late for that to
happen now because the intermediate forms would not be viable.
Once a standard is set, with all its interlocking mechanisms it's very
difficult to abandon it completely, even when much better methods are
found. That's why we still have inches and yards even though the metric
system is clearly superior. That's why we still have DOS and QWERTY.
Nature is enormously conservative, it may add new things but it doesn't
abandon the old because the intermediate stages must also work, sort of
like Microsoft. That's also why we have all the old brain structures that
lizards have as well as new ones.
3) Lack of Genetic Variation: Mutation are random and you might not get the
mutation you need when you need it. Feathers work better for flight than
the skin flaps bats use, but bats never produced the right mutations for
feathers and skin flaps are good enough.
4) Constraints of Costs and Materials: Life is a tangle of trade offs and
compromises.
5) An Advantage on one Level is a Disadvantage on Another: One gene
can give you resistance to malaria, a second identical gene will give
you sickle cell anemia.
6) Evolution has no foresight: This is the most important reason of all.
A jet engine works better than a prop engine in an airplane. I give you a
prop engine and tell you to turn it into a jet, but you must do it while
the engine is running, you must do it in one million small steps, and you
must do it so every one of those steps improves the operation of the
engine. Eventually you would get an improved engine of some sort, but it
wouldn't look anything like a jet. You just can't get to there from here.
If the tire on your car is getting worn you can take it off and put a
new one on, but evolution could never do something like that, because when
you take the old tire off you have temporally made things worse, now you
have no tire at all. With evolution every step (generation), no matter
how many, must be an immediate improvement over the previous one. it
can't think more than one step ahead, it doesn't understand one step
backward two steps forward.
>Neurons are not remotely the simplified little blobs of "neural nets",
>or the flashes of excitation we record.
I've heard that said a billion times and I think it's an exaggeration.
I hate exaggeration.
Sure neurons are ridiculously complex, but nearly all of it involves the basic
metabolism of staying alive not signal processing.
>If you can establish that a subtle effect would establish a lot of 5-QB
>computations all over the brain, with a tweak that comes with no major
>evolutionary costs, that'd be enough to win the day for ineffability.
What's the point in that? If you're a 1000 Qbit quantum computer then you're
God, if you're a network of a billion 5 Qbit quantum computers then you're a
worm.
>In particular, who needs explicit qubits?
We do in order to talk about such things.
>>Me:
>>I'm a neural net and I'm pretty good at predicting what another neural
>>net that inputs handwriting and outputs ASCII will do.
>That's because you and the neural net are optimized for the same task.
I wasn't born that way, I optimized myself to do it.
>Can you think of any NP-complete tasks that people are optimized for?
I've tried to optimize myself to solve non computable tasks but it hasn't
worked worth a damn. If I'm a neural net then my failure is easy to explain,
if I'm full of weird mysterious ineffable stuff then it's a mystery.
>Remember, I started out as a Strong AIer. I still am a Strong AIer at
>heart, just one who's been forced to believe in noncomputability.
What forced you? It seem like a strange fit for someone who wants to
program a AI. Personally I think it unnecessarily confuses an already
confusing situation. I don't need that hypothesis, it serves no function.
John K Clark jonkc@att.net
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