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Author
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Topic: Two machines seen as one
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Danpech
Member
Member # 163
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posted 05. March 2002 01:58
I feel I may be no good at the things which this forum is pursuing, and only partly because I tend to think in terms of attempting to find parallels to problems unfamiliar to me in problems that I think I have a fair grasp of.
But, here goes one of those attempts at a parallel:
Can we picture the human and the automobile together as one machine? I mean, if we can, then we can see that this 'machine' adapts to its environment to a limited extent. The human half is the part of this 'machine' that directs the adaptation, and the automobile half is the part of this 'machine' that takes on the adaptation. Is this like what plant and animal life does? Or is there more, less, or other than, this involved in life which 'allows' a plant or animal to adapt to its environment?
As for adapatation, the Eastern White Cedar trees that grow on the Niagara Escarpment (see American Scientist, Sep/Oct 1999, pg. 411-417) are not a species distinct to cliffs (they have not evolved there), but are found growing on far more hospitable terrain---and doing so better than on the cliffs.
These particular trees which grow on the Niagara Escarpment have simply adapted to the harsh condition: a poverty of places for the roots to grow. These trees are growing much more slowly than do the same trees which are found on flat, tillable ground with ample area for root growth. If the tree were strictly unintelligent, it would just keep growing on the cliffs the same way that it does on free ground: It would end up uprooting itself because the trunk and crown would quickly become too heavy for the meager anchoring of the roots. The whole tree knows to grow above-ground only as fast as its roots can support it, and this adaptive ability apparently having nothing to do with the tree having evolved this ability.
From the article, pg. 416:
quote:
By 1993, ecologists in distant parts of the world were beginning to publish studies of other cliffs, and their results had a familiar ring: Rocky precipices everywhere, it seemed, shelter an exceptionally rich collection of plants and animals. Mant types of flies, spiders, salamanders, rodents and raptors, as well as large numbers of plant species appearing nowhere else were being sighted on cliffs in many countries. Interestingly, the genera---and in some cases even the species---matched those found on the Niagara Escarpment.
From pg. 411-412:
quote:
Closer inspection of the trees on the 30-meter bluff revealed a striking pattern: The exposed wall of rock supports a sparse cover of eastern white cedar, but almost none of the tree species found in the surrounding forest (which is composed mostly of different kinds of hardwoods, including oaks, ashes and maples) reside on the cliffs.
This incongruity, we thought, signaled that the different types of trees had evolved to exploit specialized environmental conditions. Two years of work, however, showed that all these species preferred the rather lush properties of the adjacent forest; none had specific adaptations for life on the cliffs. What is more, a careful search of the bluffs for seedlings turned up almost no newly established plants.
From pg. 414:
quote:
We soon ascertained that the arctic grasses in the northern parts of the escarpment and certain ferns---are all more or less restricted to the cliffs, as are other rare plants---. These small, rare plants in some cases were much more abundant decades ago, before people eliminated much of their habitat.
The article concludes with some interesting observations, all of which the author shows make cliffs refuges of biodiversity against both the over-reaping of man and the ravages of nature.
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Niccolas L. Franz
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Member # 131
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posted 27. March 2002 07:09
Consider Redwoods. Any one redwood alone would not survive alone and be able to grow as tale as it dose. A politician once said, “When you have seen one, you have seen them all.” Now that is exactly backward from the truth. The truth is, when you have seen all of them, then and only then will you see one of them. They grow to be as tall as they do if and only if they grow in a bunch. They support each other; necessary to grow as tall as any one of them can be.
Niccolas Franz(Nic), [&&*]>[b[a&]][a[b&*]]
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James A. Barham
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Member # 50
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posted 27. March 2002 18:28
Danpech:
Thanks for the information about the intelligence of trees.
Other examples illustrating the same point could be adduced ad libitum, but it is always good to be reminded of the intelligence of living things, which bears no resemblance whatsoever to machinery, and can in no wise by explained by natural selection alone.
One of my favorites is the plasmodium Physarum polycephalum which can "solve" mazes (i.e., it will spontaneously find the shortest path through a maze cut into an agar dish by shrinking from all of the dead-end passages). This is not a talent that has been required for its survival in nature, I think, but is rather a manifestation of its general intelligence or rationality. (See T. Nakagaki et al., Nature, 2000, 407: 470.)
Or just think of the fact that bears can ride bicycles. I guess a Darwinian would have to say that this ability is a "preadaptation" or "exaptation". I guess we can call the "gene" for it "ursine cyclism."
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Danpech
Member
Member # 163
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posted 05. July 2002 22:35
Niccolas L. Franz,
You make an interesting point, and I can see something about how it is true, but it's a bit vague in my mind. I'm not quite clear on what you are referring to by saying that a Redwood cannot ideally be a Redwood (in height, etc.) unless it is growing together with many other Redwoods.
I've had the impression that any single isolated tree can be tended by humans in such a way that it grows as ideally as if it were growing in a forest of the same kind of tree. This sounds like a task generally not worth the effort, just like humans pollenating flowers without bees and such.
In contrast to this impression, and in agreement with your point, I seem to recall that some, or all, kinds of trees left to grow alone without 'competition' from other trees of any kind will grow poorly. A Flowering Cherry tree, for instance, if made to grow alone, will, I hear, tend to produce horizontal branchings that are too long for the branch-off point to support it, eventually causing these out-stretched branches to tear off from the trunk.
James A. Barham,
I'm not sure Darwin himself would have viewed "ursine cyclism" as a case of (purposeful?) preadaptation, but my own view is that the world is not made up of bits each of which have no relation to the others. My impression of Darwin is that he would have agreed with this view. The quantity of 1 is itself the root of mathematics. If you possess the root of some ability, then any skill that is not exactly the same can be learned if this skill is just a branch off of the root. If the "advanced" skill is just a branch off of two or more roots instead of just one root, then, if you possess all these roots, you can learn that skill.
Of course, no bear, nor even a whole society of bears, will learn to ride a bike on their own volition, much less make a bike to ride on.
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Frances
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Member # 169
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posted 05. July 2002 23:33
quote:
This is not a talent that has been required for its survival in nature, I think, but is rather a manifestation of its general intelligence or rationality. (See T. Nakagaki et al., Nature, 2000, 407: 470.)
Actually it could quite easily be explained by natural selection and I would not consider the solution to be intelligent. In fact it fills up all the passages and then removes those which are useless. This can be very well understood in natural selection terms.
The maze
So not only was the solution hardly that 'intelligent' it also is quite well understandable.
I assume that the comments on the bicycling bear was 'tongue in cheek'?
[ 06 July 2002, 16:01: Message edited by: Frances ]
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James A. Barham
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Member # 50
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posted 06. July 2002 08:56
Frances:
You wrote, a propos of the "maze-solving" plasmodium:
"Actually it could quite easily be explained by natural selection and I would not consider the solution to be intelligent. In fact it fills up all the passages and then removes those which are useless. This can be very well understood in natural selection terms."
My whole point is precisely that the notion of "usefulness" is (1) teleological, and (2) presupposed by selection theory. The ability to distinguish between "useful" and "useless" is precisely what I mean by "intelligence." These are not concepts that have any meaning in physics or chemistry. They are at the root of life, however.
Of course "ursine cyclism" was tongue in cheek.
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Moderator
Administrator
Member # 1
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posted 06. July 2002 10:12
Frances,
I know you mean no harm, but I am having to warn you too frequently on the use of extensive quoting. If it doesn't stop, I'm going to have to put you on temporary day-long suspension from Brainstorms.
POSTS MUST BE AT LEAST 90% ORIGINAL MATERIAL
[ 07 July 2002, 07:28: Message edited by: Moderator ]
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Frances
Member
Member # 169
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posted 06. July 2002 15:32
TO the moderator:
I apologize. I will make sure that I link to the relevant passages rather than quote them. I personally find quoting easier to read but I of course accept the moderator's wise advice. I will update the previous posting
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Frances
Member
Member # 169
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posted 06. July 2002 15:41
James states
quote:
My whole point is precisely that the notion of "usefulness" is (1) teleological, and (2) presupposed by selection theory.
Selection theory does not presuppose usefulness, usefulness is an outcome of mutations which generate potentially useful variants and the environment which selects for what is useful or not. Thus, perfectly natural processes can explain apparant teleology since the form proposed by James seems to be a backwards looking variant. Thus, Darwinism seems to provide for a fully naturalistic way of explaining teleology in nature.
Perhaps I fail to understand James' argument but he stated that "this is not a talent that has been required for its survival in nature.". My argument is that in fact it's survival in nature may very well explains its behavior. A similar behavior can be found in bacteria that can detect gradients and 'swim uphill'. Are we to suggest that this cannot be understood in natural terms?
Looking at the experiment it is clear that they first let the mold fill the whole maze and then added the food sources to which the mold responded. It's hardly an example of the mold solving the maze. Or as the researcher involved stated "To maximise its foraging efficiency, and therefore its chances of survival," says Nakagaki, the organism "changes its shape in the maze to form one thick tube covering the shortest distance between the food sources."
I would say that survival does explain the behavior of the slime mold.
I have seen references that chemical reactions such as the Belousov-Zhabotinsky reaction can solve partial differential equations in a maze. Do we now claim that a chemical reaction has an intelligence?
For details of this fascinating experiment see
O. Steinbock, A. Toth, and K. Showalter, "Navigating Complex Labyrinths: Optimal Paths from Chemical Waves," Science 267, 868-871 (1995). For a movie
[ 06 July 2002, 16:10: Message edited by: Frances ]
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James A. Barham
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Member # 50
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posted 07. July 2002 21:55
Frances:
I think we are beginning to mix up two separate issues here (I may well be at least partly to blame).
One is the general point I keep making about purpose or teleology and the logical structure of selection theory. As that is the main point, let's go over that one more time. You wrote:
"selection theory does not presuppose usefulness, usefulness is an outcome of mutations which generate potentially useful variants and the environment which selects for what is useful or not."
So, you seem to be saying (in line with a lot of philosophers of biology, such as Ruth Garrett Millikan) that it is the fact of having been selected that determines whether a trait is "useful." But how can that be? Surely it is the fact that the trait was useful that caused it to be selected!
If two types differ by a point mutation, and the mutation gives a functional advantage to one type over the other (say, superior eyesight), then surely it is the functional advantage that explains why the trait spreads through the population in succeeding generations, wouldn't you agree? That is all I am trying to get across. The theory has not explained the teleological character of the superior trait---the superior eyesight. Quite the contrary, it is the superior eyesight that explains the differential reproduction (i.e., "selection"). That is, those types that see better than the others will tend to proliferate through the population. It is obviously NOT the case (pace Millikan, Dretske, Papineau, and other Darwinian philosophers) that "selection" makes individual organisms see better! Selection works at the population level. Teleology works at the individual organism level. But it is the differences among individual organisms (differences in functional ability) that cause differences at the population level, not the other way around.
True, you can claim that the selection principle has "explained" why the trait, once it appeared, spread through the population. But, even quite apart from the difficulty of explaining the origin of novel adapative traits, the theory "explains" evolutionary change only at the price of assuming that a novel trait is functionally superior to its rivals---that is, at the price of begging the main question at issue. It is this tacit assumption of teleology that is doing all the explanatory work in selection theory.
Anyway, that is one point. The other point is about organisms' traits not being as rigidly genetically determined as is often supposed. That was the point about the bicycle-riding bears and the "maze-solving" slime molds. Obviously, both these abilities are based on general abilities with survival value. I was just making the point that the functional abilities of living things in general should be viewed from a dynamical-systems perspective, and not from a genocentric, rigidly mechanistic perspective. I admit I did not make this very clear.
[ 07 July 2002, 21:57: Message edited by: James A. Barham ]
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Frances
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Member # 169
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posted 07. July 2002 22:46
James. You raise an interesting attempt at tautology but as I have argued and shown, natura selection can be formulated in a non-tautalogous form. In fact you suggest that 'since the trait was useful, it was selected' but that is not the case. Many useful traits will remain unselected for.
Let me repeat my quote
Natural selection can be defined as a process in which
If a population has
1. variation among individuals in some trait or attribute
2. a consistent relationship between that trait and mating ability, fertilizing ability, fertility, fecundity and or survivorship (fitness)
3. a consistent relationship for that trait between parents and their offspring which is at least partially independent of common environmental effects (inheritance)
then
1. the trait frequency distribution will differ among age classes
2. if the population is not at equilibrium then the trait distribution of all offspring in the population will be predictably different from that of all parents beyond that expected from conditions a and c alone.
You responded that natural selection does not explain the origin of the trait, indeed it doesn't, that's variation a separate mechanism from selection.
There is no 'striving' of the organism to survive perse, rather the environment 'selects' for traits which affect survivorship.
So usefulness is only understood after the fact, not before the fact. Mutations are not generated with a concept of usefulness and in fact what may be useful may not be selected depending on the environment.
Again, this is a simple concept that can be tested and has indeed been tested. As far as your statement about genocentric is concerned RM&NS allows for variation in many forms.
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Frances
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Member # 169
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posted 07. July 2002 22:52
James. You raise an interesting attempt at tautology but as I have argued and shown, natura selection can be formulated in a non-tautalogous form. In fact you suggest that 'since the trait was useful, it was selected' but that is not the case. Many useful traits will remain unselected for.
Let me repeat my quote
Natural selection can be defined as a process in which
If a population has
1. variation among individuals in some trait or attribute
2. a consistent relationship between that trait and mating ability, fertilizing ability, fertility, fecundity and or survivorship (fitness)
3. a consistent relationship for that trait between parents and their offspring which is at least partially independent of common environmental effects (inheritance)
then
1. the trait frequency distribution will differ among age classes
2. if the population is not at equilibrium then the trait distribution of all offspring in the population will be predictably different from that of all parents beyond that expected from conditions a and c alone.
You responded that natural selection does not explain the origin of the trait, indeed it doesn't, that's variation a separate mechanism from selection.
There is no 'striving' of the organism to survive perse, rather the environment 'selects' for traits which affect survivorship.
So usefulness is only understood after the fact, not before the fact. Mutations are not generated with a concept of usefulness and in fact what may be useful may not be selected depending on the environment.
Again, this is a simple concept that can be tested and has indeed been tested. As far as your statement about genocentric is concerned RM&NS allows for variation in many forms.
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James A. Barham
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Member # 50
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posted 08. July 2002 18:38
Frances:
I guess we are at loggerheads and are just going to have to agree to disagree. You keep repeating Endler's schema of natural selection, and I keep pointing out that his point (2) is teleological. I really don't know what else to say.
I would just leave you with this. You say there is no "striving" in organisms. I say, tell that to the fox that chews off its own leg to escape the trap!
This striving is not limited to higher organisms, either, by any means. Check out H.S. Jennings's "Behavior of the Lower Organisms" (reprint, Indiana UP, 1962---originally publ. 1906), sometime, where he describes in detail a chase between two amoebae, one predator and the other prey. This book also contains the famous comment that "if Amoeba were a large animal, so as to come within the everyday experience of human beings, its behavior would at once call forth the attribution to it of states of pleasure and pain, hunger, desire, and the like, on precisely the same basis as we attribute these things to the dog." (p. 336).
For some comparable up-to-date examples, see Guenter Albrecht-Buehler's "Cell Intelligence" web site.
www.basic.northwester.edu/g-buehler/cellint0.htm
If these phenomena are not teleological (i.e., purposive), I don't know what is. And, to repeat, the logical structure of selection theory simply takes these, as all functional phenomena, for granted, so cannot explain them.
[ 08 July 2002, 18:43: Message edited by: James A. Barham ]
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Frances
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Member # 169
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posted 09. July 2002 00:42
James,
I do not understand your argument. You claim that the premise 2) is teleological but I fail to see any evidence of such. It's merely a premise which does not imply any usefulness other than a relationship between genes and the mating ability, fecundity, fertility etc. There is no assumption of any trait being succesful or even useful. Your initial objection was that it does not explain the origin of the trait but that's covered by mutation and variation.
There is no teleology implied in Endler's description other than in the weakest form of teleology or as Ayala states
quote:
Unbounded design or contingent teleology occurs when the end-state is not specifically predetermined, but rather is the result of selection of one from among several available alternatives. The adaptations of organisms are designed, or teleological, in this indeterminate sense. The wings of birds call for teleological explanation: the genetic constitutions responsible for their configuration came about because wings serve to fly and flying contributes to the reproductive success of birds. But there was nothing in the constitution of the remote ancestors of birds that would necessitate the appearance of wings in their descendants. Wings came about as the consequence of a long sequence of events, where at each stage the most advantageous alternative was selected among those that happened to be available; but what alternatives were available at any one time depended, at least in part, on chance events
Remember that this discussion started with your claim that the observation of maze solving abilities of the slime mold could not be explained by 'survival' when in fact that seems to be the key explanation. Furthermore you have not explained why the ability of a chemical reaction to solve a similar maze should not be seen as teleology as well?
As Dennett points out the dynamics of natural selection does not involve foresight, there is no theoretical principle even that assures that optimization takes place because of selection. Selection is merely a filter that acts upon available variation. In fact selection cannot even assume that variations that would optimize a certain situation would even arise.
In fact the premise (2) is nothing different from the statement that there is a relationship between a particular chemical element and its ability to form links with other elements based on the thermodynamic characteristics.
Should we thus conclude that the bonds in chemistry are now teleological? Does hydrogen want to bond with oxygen in the sense of 'purpose'?
I agree that organisms can show teleology in their behavior which in many cases can be understood quite well in terms of survival depending on the level of intelligence assigned to the organism. Is the ability of a bacterium to swim upstream of a food or light gradient evidence of intelligence or a mere adaptation?
More importantly even if there were teleology involved, what reason do we have to believe that it is or has to be explained by natural selection and mutation alone?
[ 09 July 2002, 00:45: Message edited by: Frances ]
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