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Friday, February 01, 2008

Uncommon Descent and the Great Debate

 
PZ Myers destroyed Geoffrey Simmons in a recent debate on radio [Was that fun, or what?]. You can hear it for yourself at [MP3].

The IDiots over on Uncommon Descent were following the debate live. It didn't go well so what did they do? They deleted the thread. Fortunately, it was preserved at Antievolution.org.

And you wonder why we call them IDiots?


[Hat Tip: Pharyngula]

16 comments :

Anonymous said...

It is actually painful to listen to Simmons in this "debate". He is astoundingly ignorant - and yet is unperturbed by his own ignorance. Faced with his own lack of data to discuss, he simply lies about the existing fossil record.

What is most disturbing is that proponents of ID want so badly for their side to be "right", that they promote/support the methods used by Simmons as reasonable argument.

Shamelessly Atheist said...

Simmons had me speachless at "there are no pre-whale fossils..."

Sigmund said...

I've heard Simmons before on the Discovery Institutes Podcast (its the only comedy podcast I subscribe to, the rest are all science). He comes across as quite painfully stupid (he literally wrote a whole book based on the notion that finding a transitional fossil means 'AHA! there are now two new gaps in the fossil record').

Anonymous said...

Geoffrey Simmons is so dumb he makes IDiots look bad. Poor PZ, but i guess that's what biologist get for "debating" idiots.

lee_merrill said...

I thought there were good points made in the posted thread.

"'As brain size increases, several problems are created', explains systems neurobiologist Jon Kaas (Vanderbilt University, Nashville, Tennessee, United States). 'The most serious is the increased time it takes to get information from one place to another.' One solution is to make the axons of the neurons bigger but this increases brain size again and the problem escalates. Another solution is to do things locally: only connect those parts of the brain that have to be connected, and avoid the need for communication between hemispheres by making different sides of the brain do different things. A big brain can also be made more efficient by organising it into more subdivisions, “rather like splitting a company into departments”, says Kaas. Overall, he concludes, because a bigger brain per se would not work, brain reorganisation and size increase probably occurred in parallel during human brain evolution. The end result is that the human brain is not just a scaled-up version of a mammal brain or even of an ape brain."

Why is it that naturalists feel the need to embellish their points and make claims that cannot be supported?

Anonymous said...

lee_merrill:

You've quoted a badly written summary of Dr. Kaas' paper. (Particularly egregious is "a bigger brain per se would not work," which is simply nonsense. This is like saying "walking upright per se would not work" because the fact that we walk upright and chimps don't causes problems for us that chimps don't have, as anyone who's ever had back spasms can tell you. *Of course* virtually all changes come with disadvantages as well as advantages. But the fact that there are disadvantages is hardly the same as not working at all.)

The full text of Dr. Kaas' article, written in 2004, is available at http://www3.interscience.wiley.com/cgi-bin/fulltext/109671897/HTMLSTART . You may wish to read it, and to pay particular note to the fact that he is careful to put all the points of the paper *within the context of evolution*. You should also note that he makes absolutely no ridiculous blanket statements along the lines of "a bigger brain per se would not work."

lee_merrill said...

> Jud: *Of course* virtually all changes come with disadvantages as well as advantages.

Certainly, but the question is whether a simple increase in brain size is practical as a general rule.

> [Dr. Kaas] is careful to put all the points of the paper *within the context of evolution*.

Which makes his conclusions more weighty when naturalist PZ says people just have a chimp brain, supersized.

> He is astoundingly ignorant - and yet is unperturbed by his own ignorance.

No such problem on the other side.

Anonymous said...

lee_merrill wrote:

"[T]he question is whether a simple increase in brain size is practical as a general rule."

Whose question was that? The particular characteristics Simmons spoke of as somehow unique to humans - chemicals released at neuronal connections, pruning of connections during development - are, as Myers said, common to chimpanzees and humans, but differ in magnitude. (Simmons repeatedly used the figure of 150,000 years for humans to develop from a common ancestor with apes, when he wasn't hinting that he also might entertain the idea of a 6,000-year-old Earth. Heaven only knows where he got that figure. Kaas' article contains a figure putting the ape-human ancestor divergence at about 20 million years.)

The rough summaries at Uncommon Descent may have oversimplified this, but you aren't relying on those oversimplifications, are you?

PZ Myers said...

What a weird idea. The claim that an enlarged brain requires reorganization to maintain functionality is nonsense -- the same pathways are there in a mouse and a human. It's patently obvious that when you can find a nigrostriatal pathway (to name one example) in both mice and men with 2 or 3 orders of magnitude difference in size, yet still similarly functional, this argument is a non-starter.

We do have some reorganizations in evolution of the brain. The visual pathway in amniotes, for instance, is much, much longer than it is in anamniotes, with at least one extra synaptic junction. Where's the premium on speed and efficiency there?

lee_merrill said...

> PZ: The claim that an enlarged brain requires reorganization to maintain functionality is nonsense...

The same problem crops up in supercomputers, you can't just keep adding more basic circuitry, because the time the signals take to travel becomes a significant fraction of the processing time. This would seem to be why we don't have language processing in our toe neurons. This is definitely why current supercomputers are composed of arrays of microprocessors, which then communicate much less frequently than (say) arrays of adders and multipliers.

> ... the same pathways are there in a mouse and a human.

We know this, only if we know all the pathways. This then involves a claim of knowledge we do not have.

lee_merrill said...

P.S. This would also be why reflexes don't involve cognitive processing, you need them to be swift in order to be effective. There are such constraints on processing time, where faster is definitely a good idea.

Regards,
Lee

Anonymous said...

lee_merrill wrote:

This [more rapid signal transmission over short distances] would seem to be why we don't have language processing in our toe neurons.

Yes, and this is also why each toe has its own spinal cord, so it can more rapidly be pulled out of the way when we step on something sharp...oh, wait.

See, lee, this nonsense is what you get when people with no knowledge about the subject they're discussing start reasoning "logically."

PZ Myers said...

The same problem crops up in supercomputers, you can't just keep adding more basic circuitry, because the time the signals take to travel becomes a significant fraction of the processing time.

You seem to have missed the significant counterexample I mentioned. A frog has eyes that project to a midbrain center, the optic tectum, for visual processing. A mammal has eyes that project to the midbrain, which then projects to the visual cortex, at the very back of the brain, for visual processing.

We don't seem to have visual circuitry that is in any way optimized for path length or for minimizing the number of slow synaptic connections. It's baffling to me why people would point to examples of how computers work when the counterexamples in brain organization are so obvious...and it's the evolution of the brain that we're talking about, so I know which one trumps which.

lee_merrill said...

> PZ: We don't seem to have visual circuitry that is in any way optimized for path length or for minimizing the number of slow synaptic connections.

But I didn't mean that every processing function has a pressing time constraint. Some functions however, do, that was the reason for the mention of reflexes.

> Jud: Yes, and this is also why each toe has its own spinal cord, so it can more rapidly be pulled out of the way when we step on something sharp...oh, wait.

I'm not sure what you mean here, though. The point in this case was that certain functions need to be quick, and certain interdependent functions need to be quick, and routing connections longer distances make these slower, perhaps crucially slower.

Now I heard on Discover channel (must be true!) that we get bombarded with about 11 billion bits of information a second or so, and we can process about half a hundred.

So then we must get this processing done post haste, to reduce the amount of information to a reasonable level.

Another interesting article along this line is here, where vision processing gets done in a split second, before we are even aware that we have seen.

So such systems do have some real-time constraints, and not getting the job done in time would cause problems.

Anonymous said...

lee_merrill wrote:

I'm not sure what you mean here, though. The point in this case was that certain functions need to be quick.

Yeah, "certain functions" like pulling your toes up rapidly when you step on something sharp, which was my example. Our nervous systems send those signals all the way to the spine and back, rather than localizing processing for minimum signal processing time, which is the incorrect concept you're trying to impose on human nervous system evolution.

*Your* example was lack of language processing centers in toe neurons. Gosh [smacks head], why didn't I think of the fact that we have our language processing centers in our mouth neurons for minimum signal processing time!

Unknown said...

The same problem crops up in supercomputers, you can't just keep adding more basic circuitry,

Disregarding that yesterdays supercomputers are todays desktops, invalidating your argument.

Not to mention that today the fastest Blue Gene/P tops at ~ 1 petaflops (10^15 flops) while typical desktops are ~ 100 Gflops (10^11 flops) or 4 orders of magnitude away instead of the mere 2-3 orders of magnitude discussed here.