Quote of the Day - 12 July 2005

| 12 Comments

Yes, I actually am going to try to get a quote up every day. I’m also going to try to keep them at least moderately relevant to this blog’s topic. Some will be short and sweet, and some will be accompanied by commentary. Today’s is one of the commentary ones.

It has now been shown, though most briefly and imperfectly, how the law that “Every species has come into existence coincident both in time and space with a pre-existing closely allied species,” connects together and renders intelligible a vast number of independent and hitherto unexplained facts. The natural system of arrangement of organic beings, their geographical distribution, their geological sequence, the phaenomena of representative and substituted groups in all their modifications, and the most singular peculiarites of anatomical structure, are all explained and illustrated by it, in perfect accordance with the vast mass of facts which the researches of modern naturalists have brought together, and, it is believed, not materially opposed to any of them. It also claims a superiority over previous hypotheses, on the ground that it not merely explains, but necessitates what exists. Granted the law, and many of the most important facts in Nature could not have been otherwise, but are almost as necessary deductions from it, as are the elliptic orbits of the planets from the law of gravitation. –Alfred Russel Wallace ON THE LAW WHICH HAS REGULATED THE INTRODUCTION OF NEW SPECIES (1855)

Commentary on the flipside.

The interesting thing about this quote is that it really contains a very compelling argument for evolution, three years ahead of schedule. The only thing Wallace is missing here is a mechanism. Well, that and an explicit statement that supports common descent, but he comes very close to that earlier in the paper.

Wallace’s 1855 paper, and it’s influence (or lack thereof) on Darwin, Lyell, and other noted naturalists is discussed in depth in David Quammen’s book The Song of the Dodo, a book that is well worth reading.

12 Comments

The only thing Wallace is missing here is a mechanism.

Perhaps in Wallace’s 1855 paper, but in Wallace’s 1858 manuscript “On the Tendency of Varieties to Depart Indefinitely From the Original Type”, Wallace introduces the correct mechanisms: inherited variation and natural selection.

This is the famous manuscript sent to Darwin:

Alfred Russel Wallace (1858) Wrote:

It will be observed that this argument rests entirely on the assumption, that varieties occurring in a state of nature are in all respects analogous to or even identical with those of domestic animals, and are governed by the same laws as regards their permanence or further variation. But it is the object of the present paper to show that this assumption is altogether false, that there is a general principle in nature which will cause many varieties to survive the parent species, and to give rise to successive variations departing further and further from the original type, and which also produces, in domesticated animals, the tendency of varieties to return to the parent form.

The life of wild animals is a struggle for existence. …

Oh, and since we’re doing quote of the day here, Darwin had this to say of Wallace’s 1858 manuscript:

Charles Darwin in a Letter to Charles Lyell Wrote:

My dear Lyell

Some year or so ago, you recommended me to read a paper by Wallace in the Annals, which had interested you & as I was writing to him, I knew this would please him much, so I told him. He has to day sent me the enclosed & asked me to forward it to you. It seems to me well worth reading. Your words have come true with a vengeance that I shd. be forestalled. You said this when I explained to you here very briefly my views of “Natural Selection” depending on the Struggle for existence.—I never saw a more striking coincidence. If Wallace had my M.S. sketch written out in 1842 he could not have made a better short abstract! Even his terms now stand as Heads of my Chapters.

Please return me the M.S. which he does not say he wishes me to publish; but I shall of course at once write & offer to send to any Journal. So all my originality, whatever it may amount to, will be smashed. Though my Book, if it will ever have any value, will not be deteriorated; as all the labour consists in the application of the theory.

I hope you will approve of Wallace’s sketch, that I may tell him what you say.

My dear Lyell | Yours most truly | C. Darwin

“In the brain of the lowest savages and, as far as we know, of prehistoric races, we have an organ … little inferior in size and complexity to that of the highest types … But the mental requirements of the lowest savages, such as the Australians or the Andaman Islanders, are very little above those of many animals. How then was an organ developed far beyond the needs of its possessor? Natural Selection could only have endowed the savage with a brain little superior to that of an ape, whereas he actually possesses one but very little inferior to that of the average members of our learned societies”

–Alfred Wallace

Qualitative:

Good quote. Wallace asks an important question. Of course, the answer could be “magic” or goddidit and we’re done with it, but let’s try to do better. Unless those answers satisfy you, of course. I find them just another way of saying “I don’t know”.

I’d like to hear some of our biologists on this topic. I’ve read Gould’s rather extensive treatment of spandrels and exaptations. These imply that complex brains arose as a side-effect of some other useful characteristic (language? symbolic thinking?) I’ve also seen evo-devo explanations attempting to track down how such changes may have gotten started because some gene turned on a little earlier, etc.

Did Wallace himself propose an answer? What do you think happened?

Flint -

Personally, I think Wallace simply made a mistake here, a mistake driven by contemporary cultural biases. Although the human brain eventually allowed the construction of complex agricultural and technological societies in some places, anatomically modern brains were selected for long before any of that happened, almost certainly before there were humans in Australia, for that matter. Obviously, even though hunter-gatherers aren’t writing computer programs to extend the digits of pi or whatnot, a large human brain was selected for in that millieu.

It makes sense of course. Humans had to get “smart enough” first, and then build “civilizations”. You can’t build civilizations first, and then get smart enough to use them after the fact. Only a version of creationism would allow the latter series of events.

There’s overwhelming evidence that large brain size was selected for during a long period in the past, and little or no evidence that any of the poorly defined traits we define as “intelligence” is being selected for one way or the other in the historical era. One might conjecture that some aspect brain anatomy would in some way be selected for in “civilization”, resulting in a gradual accumulation of differences in brain anatomy between “civilized” and hunter-gatherer populations, but as Wallace noted, the evidence is to the contrary.

It’s difficult to quantify the “mental requirements” of a hunter-gatherer life. It strikes me that it may be more cognitively demanding, in many ways, than the life of the “average” person in an industrial society.

Also, the size of the human head is already somewhat problematic. Of course, larger adult heads need not be expressed as larger heads at birth, but even so, changes in brain anatomy that result in head size increase might no longer be as benign with respect to natural selection, as they were up to the size we now possess.

A more logical question is why certain civilizations arose at certain parts of the world at certain times, and not in other parts at other times. The logical answer is that human intelligence is sufficient to produce a complex society, given a variety of other circumstances. It’s the other circumstances that vary over time and space. If we were to foolishly use the local state of technology to judge the “intelligence” of a population, we would have to conclude, almost certainly falsely, that Northern Europeans were very “stupid” 1500 years ago, but now have become very “smart”, over a very short number of generations.

harold:

Maybe I wasn’t clear (or Wallace wasn’t?) I doubt the capabilities of the human brain have changed materially (if any at all) since our species first appeared. We don’t know our exact lineage and may never know it, so I don’t know how many branchings brain capacity went through. I would tend to doubt it happened all in one go. But I read Wallace as pointing out that when our species originated, it had enough brainpower to support our complex modern society, and by all indications this was WAY overkill for the societies of the day. So I suspect what actually evolved was some extremely useful capability for which a lot of brain capacity was required, and we have taken advantage of the remainder. So I speculated that useful capability was language or symbolic thinking.

Flint -

Not much argument here. But I’m not sure we know this…

“by all indications this was WAY overkill for the societies of the day”

I agree with your points about language and symbolic thinking. But there are many other ways to use a brain as well. Have you ever read “The Works and the Days” by Hesiod? If not, I don’t recommend it, unless you’re a social historian (I’m not, of course, but it I am fascinated by the stuff). It’s pretty boring. But it’s a description of the life of “simple” agriculturalists at the end of the so-called “Dark Ages” of Ancient Greece. It isn’t exactly entirely what we would call “rational”, but it isn’t all that “simple” either.

It’s full of knowledge, and a lot of the “superstition” is actually more mnemonic - a justification for doing something that’s right for another reason, or more charitably, a way to remember how to do it. And Hesiod could write. The other guys had to keep it all in their heads.

Most hunters have pretty complicated lives as well. Animals migrate around at different times of year, leave different tracks, require different hunting methods, and so on. And then you have to prepare them properly for eating. Even these days, you can’t just go into the woods with an Uzi - you have to have some clue what you’re doing.

How much “smarter” are we? How many neurons does it take to roll out of bed into an air-conditioned room, and drive to work, even if your job is being an engineer at the air-conditioning company research center, or running PCR for the FBI? Sure that car is complicated, but thousands of humans worked together, each on a specialized task (often conceptually simple) to produce it. Is that one guy tracking down a moose and bringing it down with a flint arrow using less “intelligence”? Maybe not. Maybe quite the contrary. (Actually, I prefer elk.)

Animal lovers -

I don’t hunt. I was raised not to hunt in an area where everyone hunted, for reasons of family tradition. I don’t consider hunting “bad”, but if I did it, I’d use every part of the animal I could. I’m vehemently opposed to cruelty to animals (I don’t consider skillful hunting for sustenance part of that category, nor valid humane research on domestic mice or similar species, but we can agree on the rest). No flames please.

But I read Wallace as pointing out that when our species originated, it had enough brainpower to support our complex modern society, and by all indications this was WAY overkill for the societies of the day.

I don’t think our “societies” are any more “complex” than theirs were. People are still people.

We just have bigger shinier toys, and more of them.

A more logical question is why certain civilizations arose at certain parts of the world at certain times, and not in other parts at other times.

Economics.

Societies have to stay alive, within the circumstances that they find themselves in. Different circumstances, different ways of staying alive, different societies.

I think much of the reason why the Europeans explored, invaded and conquered the world, and not, say, the Chinese, is because Europe is the smallest of the continents. They simply HAD to go somewhere else.

A more logical question is why certain civilizations arose at certain parts of the world at certain times, and not in other parts at other times.

Read Jared Diamond’s “Guns, Germs, and Steel”.

I wrote -

“A more logical question is why certain civilizations arose at certain parts of the world at certain times, and not in other parts at other times”.

I got two answers, both of which I agree with.

But this was more or less a rhetorical question, so to speak. I went on to say…

“The logical answer is that human intelligence is sufficient to produce a complex society, given a variety of other circumstances. It’s the other circumstances that vary over time and space.”

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This page contains a single entry by Mike Dunford published on July 12, 2005 2:14 AM.

Carl Zimmer: Tangling the tree was the previous entry in this blog.

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