Teleology and biology

Contra Noah Millman, who recently claimed, "we can’t rely naively on an Aristotelean teleology which we now know has no empirical basis" (God knows what he meant here!), teleology pervades modern biology, and there is absolutely no sign it can be gotten rid of. Take this report of recent sloth research in the NY Times: I find at least the following uses of teleology in explaining what the sloths are up to, with the key teleological words highlighted:

"[the three-toed sloth] has carved out a remarkably ingenious mode of life in the treetops" (Something is ingenious in that it achieves an end very economically.)

"Why then does the sloth take such a risk every week?" (For what end?)

"They started by trying to understand what would compel the sloth to brave the dangers of a weekly visit to ground zero." (To what end would it do so?)

"Rather, they assumed, it was to favor a critical component of the sloth’s ecosystem, the pyralid moth. The descent to the sloth’s midden affords the pregnant moths in its fleece a chance to lay eggs." (The behavior has the end of helping the pyramid moth.)

"The researchers guessed that the sloths might be eating the algae from their own fur, and that this could be the purpose of the whole system." (No comment needed.)

"But the invention of giving over its fleece to algae farming would go a long way to solving its problem of limited nutrition." (The solution to the problem is the end that the system moves towards.)

And it has been decisively demonstrated that such language cannot be being translated into mere descriptions with the teleology yanked out, without a huge loss of meaning. When the scientists conclude that the purpose of the sloths coming to the ground is to help the moths that is not equivalent to saying that it just happens that their doing so helps the moths. Because the sloths descending to the ground also happens to help the jaguars that sometimes eat them, but no scientist would ever say that the sloths descend to the ground with the purpose of feeding themselves to the jaguars. Helping the moths is what the behavior is for, while helping the jaguars is an accidental byproduct of the behavior.


"Hey, who you sayin' got no purposes? You just stay right where you are for about a week or so, and I'll hurry right over there to kick your butt!"

26 comments:

  1. The Selfish Gene is back in print. So is Dennett.

    This is like anything with different levels of explanation Gene. You need beliefs to talk about minds, but that doesn't mean you can't talk about beliefs in terms of brain states.

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    1. "but that doesn't mean you can't talk about beliefs in terms of brain states."

      THAT doesn't mean that you can't, but, in fact, one can't: as Donald Davidson puts it, moving from beliefs to brain states, one has changed the subject.

      But what does that have to do with my post, anyway?

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    2. The teleology you discuss can be reduced. TSG does it. Minds are just another example.
      If we are talking about the stability of your porch discussing its nails and trusses is not changing the topic.

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  2. Why can't you eliminate the teleological description by saying that its genes cause the sloth to instinctually come down from the tree, and the cause of that gene being prevalent in sloths is that it increases survival advantage, since it helps the moths? By the way, I actually am a firm believer in teleology, but I don't think the scientists are really invoking teleology here. This seems to just be a case where teleology is being used as a metaphor for natural selection.

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    1. "and the cause of that gene being prevalent in sloths is that it increases survival advantage, since it helps the moths"

      Teleology.

      The gene does this for the purpose of helping the moths.

      Otherwise, you are going to be in the position of just looking at every single living event and saying "Genes. Genes. Genes. Genes."

      Or ask yourself this: why did the scientists spend years trying to figure out why this logs came down from the trees? They knew the answer "Genes" from day one. They were asking "What *purpose* does this serve?"

      Are you sure you are confusing the idea of a telos with that of a conscious purpose?

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    2. "The gene does this for the purpose of helping the moths." You can remove the teleological description there too, by saying that the gene has the effect of causing the moths to be helped, increasing the survival advantage of the sloth, and thus the gene had a good chance of being passed on, which is the cause of sloths having that gene today.

      "They knew the answer "Genes" from day one. They were asking "What *purpose* does this serve?"" Well, they knew that a gene was the cause, but they were trying to find out, what caused this gene to be passed on? What effect did it have on the sloth's survival that made it likely that it would be passed on?

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    3. "What effect did it have on the sloth's survival that made it likely that it would be passed on?"

      Right: what was its purpose?

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    4. It seems to me that you're watering down Aristotle's notion of final cause. If a particular rock is really heavy, which causes it to not be blown away in the wind, would you say that the purpose of its heaviness is to not be blown away in the wind? How does that differ from you saying that the purpose of a gene is to confer survival advantage, just because it has the effect of causing the sloth to have increased survival advantage?

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    5. "It seems to me that you're watering down Aristotle's notion of final cause."

      Not at all. Ask an Aristotle expert like Feser or Long.

      It is the purpose of the behavior we are seeking. And it is very specifically not whatever it just happens to do that we dub its purpose. The sloth coming to the ground happens to feed jaguars, and allow naturalists to take its photograph more easily. But THOSE were not plausible explanations these scientists would accept! No, what the behavior is FOR is to complete the life cycle of the moth.

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    6. What distinguishes helping the moths from feeding the jaguars and being photographed is that feeding the jaguars, for instance, is not the effect of the descending-the-tree gene that is the efficient cause of the gene being in the sloth. Rather, the efficient cause of the gene being in the sloth is the effect that the gene had on helping the moths.

      To put it another way, the efficient cause of the sloth descending the tree is the sloth's ancestors surviving due to descending the tree and helping the moths. Where is the discussion of purpose in that description?

      Now if you want to use "what is the purpose of the sloth's instinct to go down" as a shorthand for "what was the efficient cause of the sloth's ancestors survival when they had the instinct to go down", that's an odd use of the word purpose. As I said, I think the scientists are just using purpose as a metaphor.

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    7. "Rather, the efficient cause of the gene being in the sloth is the effect that the gene had on helping the moths."

      No, this is all together wrong. The efficient cause is the biochemical reactions that created it! You've just tried to hide a teleological description by calling it an efficient cause!

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    8. And, of course, even the biochemical reactions will exhibit teleology.

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    9. What you are arguing is that because biologists, like most people, find certain metaphors and ways of speaking useful, the universe must be pervaded by purpose. This just isn't so.

      Like most discipline biology borrows and specializes words. This is like "work" in physics. When, as you seem to do, you stretch such biological usages beyond their specialized meaning you change the assertions being made.

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    10. Let me elaborate, since I might be a bit unclear. You can't really DO biology without evolution by natural selection, and the notion of an adaptation. And you can't really do that without the notions of purpose, reason, etc. So on that I think pretty much everyone agrees. But you can't conclude that really truly the grass feels a desire to grow and found your biology on a belief in that desire divorced from the evolutionary theory that defines that goal. Some people want to take that goal seeking and then say "AHA! You don't need natural selection!". That's the error I mean.

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    11. Forget biochemical reactions, by that argument you could say that the real efficient cause is the interactions of subatomic particles. I don't think the scientists (unless they're religious) would dispute the claim that in principle, the behavior of the sloth is completely explainable in terms of behavior of subatomic particles. But how humans generally talk is by grouping large numbers of particles into large objects, and grouping large numbers of particle-level interactions into interactions between large objects. So in that sense, we can talk about a gene causing a descent from the tree, and about helping the moths causing a sloth to survive.

      So again, we're saying that the efficient cause of the sloths descending from trees is the effect of the descent-from-tree gene. The efficient cause of having their having the gene to do so is the ancestors of sloths who survived having that gene. The efficient cause of those ancestors' survival is the helping of moths. And the efficient cause of the ancestors helping the moths is those ancestors having the descent-from-tree gene. Where am I hiding a teleological description in any of that?

      So when scientists talk about the purpose of the sloths descending from the tree, all they're really talking about is the intermediate efficient causes (at the macroscopic level of description).

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    12. So, sloths don't really exist, but are just a way humans happen to group things when they talk?! Then scientists must not really exist either, and are really just a way sub-atomic particles... Oy, if you're going to babble complete nonsense, I really don't know how to respond.

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    13. @Bodybuilder: "What you are arguing is that because biologists, like most people, find certain metaphors and ways of speaking useful..."

      No way, uh-uh. Biologists find explanations in terms of functions (which are teleological) *indispensable*. The entirety of biology would collapse without functional explanations.

      "When, as you seem to do, you stretch such biological usages beyond their specialized meaning..."

      So, when a biologist says "The function of the heart is to circulate blood," just how I am "stretching" that meaning?!

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    14. @Bodybuilder: "But you can't conclude that really truly the grass feels a desire to grow..."

      You have severely misunderstood the notion of a final cause. It has nothing to do with whether the grass feels anything or not:
      http://edwardfeser.blogspot.com/2009/09/teleology-revisited.html

      'Some people want to take that goal seeking and then say "AHA! You don't need natural selection!". '

      So, because some people might do something stupid with teleology, we shouldn't use it?!

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    15. Well, that's at least what reductionistic materialists believe. Now you may disagree with that (as do I), but they believe that all phenomena can in principle be explained in terms of the behavior of particles, but since some large collections of particles behave in ways that are coherent and organized, humans tend to view them as single objects. That's not to say that the ways that humans group the particles are arbitrary; they are after all based on empirical observations about how certain particles act in concert.

      But in any case, I only brought up subatomic particles to make the point that rejecting a putative efficient cause because it doesn't reference biochemical reactions is just as pointless as rejecting it for not referencing subatomic particles.

      The point is, regardless of whether biochemistry, subatomic particles, emergent phenomena, or Cartesian egos ultimately explain macroscopic objects, at the macroscopic level we can talk about genes causing behavior and survival of an animal causing the inheritance of genes. So in that context, where do you think I'm smuggling in a teleological description in my sequence of efficient causes in my last comment?

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    16. @Mathman: " I don't think the scientists (unless they're religious) would dispute the claim that in principle, the behavior of the sloth is completely explainable in terms of behavior of subatomic particles."

      Well, I would certainly hope they would dispute it, because the idea is preposterous. From the "point of view" of subatomic particles, not only would a sloth not be explicable, it would not even be visible. The world of physics is an *abstraction* from the real world, and certainly not a "complete" explanation of it!

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    17. Yes, I agree with you that physics does not completely explain reality, but lots of other people disagree. They think there is no real world apart from the world of physics.

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    18. "No way, uh-uh. Biologists find explanations in terms of functions (which are teleological) *indispensable*. The entirety of biology would collapse without functional explanations." I think in biology, "function" is just a shorthand for "what led to the relevant genes being passed on", which is purely a matter of sequence of efficient causes.

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  3. Well, I'm convinced. Question is, what are the implications of this?

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    1. Well, for one, biologists can stop fighting the idea of living things having ends.

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  4. @mathman: "Well, that's at least what reductionistic materialists believe. Now you may disagree with that (as do I), but they believe that all phenomena can in principle be explained in terms of the behavior of particles,"

    Well, lots of people believe Elvis is still alive.

    But I didn't reject "natural selection" as an efficient cause because it doesn't reference biochemical process!!! I rejected because it is not a cause of anything at all! It is a principle of explanation, but nothing whatsoever has ever been *caused* by natural selection!

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    1. I didn't claim that natural selection caused anything either. I just said that genes can cause behavior, and the survival of organisms can cause the inheritance of genes.

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