tag:blogger.com,1999:blog-2814994353835004156.post1442373522615533241..comments2023-12-18T20:54:23.723+00:00Comments on philosomama: Analogies, evolutionary forces, and a shiny new journalEllen Clarkehttp://www.blogger.com/profile/16849531733597762341noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-2814994353835004156.post-4908351018875076952014-06-01T03:09:53.570+01:002014-06-01T03:09:53.570+01:00Hi Chris,
I find your claim that "our concer...Hi Chris,<br /><br />I find your claim that "our concern in the present paper is with the analogy for its own sake" [from the introduction to the paper] to be problematic.<br /><br />If the concern is the analogy for its own sake, then the conclusion is an accurate sociological/ historical/ scientific description of how we talk and think about evolution currently. But this isn't a philosophically innocent endeavor. There is the divide between the statisticalists and the causalists, and I suspect each thinks about evolution in significantly different ways from the other. So I doubt there is an independent view of the analogy outside some causalist/ statisticalist bias. It is a loaded issue.<br /><br />So what I was responding to above was that I got a bit of a causalist bias since you "are saying that the story about the world that is told by evolutionary biology is like the story about the world told by Newtonian mechanics". I took this to be a biased position against the statisticalists, and was saying that the statisticalists could provide analogies that would tilt evolutionary biology their way. Everyone can insist their analogies are the right analogies, but, without further argument, this is only to reiterate one's basic position. <br /><br />Appealing to the amorphous nature of physical forces, as I took EC to be saying, won't help solve this problem.<br /><br />Noahhttp://noahgreenstein.com/wordpressnoreply@blogger.comtag:blogger.com,1999:blog-2814994353835004156.post-18898094989482274922014-05-31T21:40:38.629+01:002014-05-31T21:40:38.629+01:00Hi Ellen,
I worked quite hard on the Price equati...Hi Ellen,<br /><br />I worked quite hard on the Price equation way back when André and I were working on our 2002 paper. At the time, I concluded that it was not fundamentally different with respect to this point than Fisher's theorem or general descriptions. My position has always been that you cannot separate out the contributions of these factors in <i>individual</i> histories. You can do so for the <i>type</i> of situation that is presented by a population in a certain situation. In other words, my claim is that it is one thing to say that 65% of the time, a situation such as that faced by the hominin population 500,000 ya, language would evolve (or that this is the probability of this outcome) and another thing to say that in the actual evolutionary history of human language, selection was 65% responsible. I actually don't think the second has any clear meaning. A quick look at Steve Frank's paper leads me to think that he is talking about mutation rates and selection strength. I could be wrong, of course, and please correct me if I have missed something essential, but the paper doesn't seem to be new with regard to the point in question. Mohan Matthenhttps://www.blogger.com/profile/18412367867949250445noreply@blogger.comtag:blogger.com,1999:blog-2814994353835004156.post-29465787979706159932014-05-31T11:18:07.874+01:002014-05-31T11:18:07.874+01:00Here's a link.....
http://stevefrank.org/abst...Here's a link.....<br /><br />http://stevefrank.org/abstracts/12NS03.html Ellen Clarkehttps://www.blogger.com/profile/16849531733597762341noreply@blogger.comtag:blogger.com,1999:blog-2814994353835004156.post-29493321863661521852014-05-31T11:14:41.018+01:002014-05-31T11:14:41.018+01:00Following the same point......
Mohan you said &quo...Following the same point......<br />Mohan you said "you cannot disaggregate the contributions that the various Sober-forces make to an individual evolutionary change."<br /><br />I wonder if Price's equation doesn't give us one way we can disaggregate component forces of the total evolutionary change of a population. Steve Frank has a nice series of papers in Journal of Evolutionary Biology explaining how we can separate the evolution that is due to natural selection from the evolution that is caused by transmission bias. Admittedly, this doesn't exactly line up with a decomposition into selection, drift, mutation and migration. Rather, the transmission bias term incorporates mutation, lower-level selection and drift. But we can separate these out in models at least, holding one or more of them constant.Ellen Clarkehttps://www.blogger.com/profile/16849531733597762341noreply@blogger.comtag:blogger.com,1999:blog-2814994353835004156.post-56288694356070989852014-05-30T23:03:18.830+01:002014-05-30T23:03:18.830+01:00Hi Chris,
Thanks for your response. In the intere...Hi Chris,<br /><br />Thanks for your response. In the interests of not getting into an endless back and forth, I'll restrict my comment to something new that arises out of your reply.<br /><br />Here is a heuristic way of putting my point about selection and drift. Selection is a chance process; drift is the departure from expectation in that chance process. To suggest that such departures require an additional cause ("drift as process," as Roberta Millstein calls it) is to suggest <i>contrary to assumption</i> that selection is deterministic and departures are explained by interfering causes. (Sober does actually say something like this, but he has to add the caveat that selection is deterministic <i>in infinite populations</i>. True, but there's also no drift in infinite populations.)<br /><br />Your point about mutation and migration being closer to Newtonian forces is interesting. Mutation and migration can be disaggregated post facto, and this is an important point. The only problem in the general theoretical context is that these too are probabilistic. Mutation figures in the mathematical theory as a mutation <i>rate</i>, and I would argue that you can't disaggregate mutation rates from selection even post facto. <br /><br />A further complication—and I am not sure as yet what to make of this—is that mutation and migration rates figure in the selection process. For instance, a propensity to increase mutation rates when stressed may be adaptive; similarly for migration. Mohan Matthenhttps://www.blogger.com/profile/18412367867949250445noreply@blogger.comtag:blogger.com,1999:blog-2814994353835004156.post-91176458682145067322014-05-30T17:42:58.246+01:002014-05-30T17:42:58.246+01:00Mohan, thanks for your comments.
1. I agree with ...Mohan, thanks for your comments.<br /><br />1. I agree with you about what Sober says. He seems to think there is a sense of ‘force’ such that we can talk about theories of forces other than Newtonian Mechanics. NM is the most familiar theory of forces but not the only one. I agree with what I think you are suggesting: there isn’t a clear sense of force outside of the context of NM. In particular, I would have a hard time making sense of someone who said: “Theory X is a theory of forces. Even though ‘forces’ in theory X are almost completely different from forces in NM, they still have property Y, which is the essential feature of forces.” I don’t know what could tell us what the essential properties of forces are if not NM. So you were certainly right, in challenging Sober, to try to identify differences between evolutionary forces and Newtonian forces. I also agree that the dynamical view has evolved on these issues, in part in response to your criticisms.<br /><br />2. In the text, we don’t claim that Brownian motion is a force. We included it in the diagram just to indicate what we thought the closest Newtonian analogs of various evolutionary forces are. We say in the text the drift is the least force-like of the alleged Newtonian forces, and that there are important issues about the role of probability in evolutionary biology for which the analogy with Newtonian forces is unenlightening. So we are not claiming that all evolutionary forces are perfectly force-like. Part of our point is that some of the most force-like are the ones receiving relatively little attention, like mutation and migration. <br /><br />3. Part of the point that we were making in the section on composition of forces is that you can’t desegregate the over-time effects of individual Newtonian forces either. E.g. if a test particle, experiences gravity due to two masses m1 and m2, and after ten seconds it has deflected 10 meters south of where it would have been in the absence of forces, you can’t decompose that 10 meters south into components due to m1 and m2. (As we note in the paper, this point is made very nicely and in more detail in a paper by Sheldon Smith.) <br />Christopher Hitchcockhttps://www.blogger.com/profile/10232394766065633104noreply@blogger.comtag:blogger.com,1999:blog-2814994353835004156.post-74538065388829303972014-05-30T17:19:05.467+01:002014-05-30T17:19:05.467+01:00Noah, thanks for your comments.
(BTW, I won’t cla...Noah, thanks for your comments.<br /><br />(BTW, I won’t claim to speak for Joel in anything I say here.)<br /><br />Let’s distinguish two different claims:<br /><br />1. Evolutionary forces such as selection, drift, migration, and mutation are analogous to Newtonian forces such as gravity, electrostatic attraction/repulsion, friction, and spring forces.<br /><br />2. Evolutionary forces are causes of changes in gene frequencies in a population (and they can sometimes cause stasis as well).<br />In our paper, we argue for 1 (although we demur to a considerable extent on drift). We don’t argue directly for 2, although many will think that 1 lends strong support for 2.<br /><br />So suppose someone makes the following argument (I don’t attribute this to you, but maybe it is in the ballpark of what you are considering):<br /><br />i. Natural selection is more closely analogous with friction than with gravity.<br /><br />ii. Friction does not cause deceleration and heating, since all of the causation occurs at the level of fundamental forces. <br /><br />iii. Therefore, natural selection does not cause changes in gene frequencies, since all of the causation goes on at a lower level. <br /><br />Nothing we say in the paper is intended to refute this argument; in particular, we don’t challenge premise (ii). In fact, I would be happy if someone making this argument cited our paper in support of premise (i). Personally, I don’t find premise (ii) very compelling. (I’ve written about this briefly in the context of the causal exclusion argument in philosophy of mind.) And I don’t read any of WALM as being skeptical of micro-causation generally. But nothing in the present paper is aimed at refuting premise (ii).<br /><br />We are claiming that evolutionary biology is analogous to Newtonian mechanics in certain respects. Newtonian mechanics is not literally true, so in saying this, we are saying that the story about the world that is told by evolutionary biology is like the story about the world told by Newtonian mechanics (regardless of whether the latter is true). One problem with saying this is that “Newtonian mechanics” is much less clearly defined than most people realize. It is not a formal system with a fixed list of axioms like ZFC. And there are lots of branches of classical physics that loosely fit together: continuum mechanics, rigid body mechanics, Lagrangian and Hamiltonian mechanics, etc. I think that those who make an analogy between evolution and Newtonian mechanics have in mind something like: the physics you learn in a first year university physics course. This is classical mechanics with discrete bodies and discrete forces. <br /><br />If you look at the way friction is presented in such a course, it is essentially treated as an autonomous force. There may be a hand-wavy gesture at the possibility of explaining friction in terms of more fundamental forces, but this is not in any way a central theoretical commitment of the theory being presented. So the main claim we wanted to make here is that the reducibility of friction is not an essential part of the story NM tells about the world. A possible world in which friction is primitive is still a Newtonian world. Friction, whether reducible or not, is very much a force in the context of NM. <br />Christopher Hitchcockhttps://www.blogger.com/profile/10232394766065633104noreply@blogger.comtag:blogger.com,1999:blog-2814994353835004156.post-25635555983052403822014-05-29T23:25:56.431+01:002014-05-29T23:25:56.431+01:00It's funny, but I can't find where Sober s...It's funny, but I can't find where Sober says that evolutionary theory is analogous to a theory of forces. The title of his chapter suggests that one can treat it as a theory of forces. The closest I can find is on page 14: "The theory may be thought of in analogy with Newtonian mechanics. Various forces are described, but the theory has at its conceptual center a view of what will happen to the systems it describes when no forces at all impinge." It was Chris Stephen's who said, discussing my and Andre's piece, that "the analogy between evolutionary theory and Newtonian <i>mechanics</i> was never intended to be perfect. However that may be, Sober always assumed that there was a clear sense of force, and that evolutionary theory is quite literally a theory of forces. This is actually what the quote from Sober I have just given seems to presuppose.<br /><br />A more substantial point. Hitchcock and Velasco say that friction never acts by itself, but always in conjunction with other forces, such as the force of gravity that pulls an object down on another, thus creating friction. "This undermines the claim of Matthen and Ariew that Newtonian forces (unlike evolutionary forces) can always be considered in isolation." This is a welcome clarification. However, we never meant to say that all Newtonian forces can act in the absence of other forces. (I doubt we even ever said that, though I'd have to check: we never discussed the point, so it's possible we were careless.) Rather our point was that in evolutionary theory, you cannot disaggregate the contributions that the various Sober-forces make to an <i>individual</i> evolutionary change. So you CAN say that friction was one-fifth the force of gravity, but you cannot say that in the evolution of the human opposed thumb, drift accounted for one-fifth of the final result.<br /><br />Finally, I note with some bemusement that Hitchcock and Velasco list Brownian motion as a Newtonian force. Brownian motion is a paradigm for our critique. Like drift, it is the product of uncertainty in an ensemble, not a cause of it.Mohan Matthenhttps://www.blogger.com/profile/18412367867949250445noreply@blogger.comtag:blogger.com,1999:blog-2814994353835004156.post-39258276566318635562014-05-28T15:59:13.899+01:002014-05-28T15:59:13.899+01:00Hi.
Good review of the paper, but I take issue wi...Hi.<br /><br />Good review of the paper, but I take issue with your appeal to the unknown as a defense of V&H's causalist position. You said:<br /><br />>If there is anything magical about thinking of natural selection as an overall force producing all the multifarious births and deaths that we actually observe, then it is in very good company lumped in with physical forces.<br /><br />Explaining something unknown by appealing to something even less understood is not a good strategy (ignotum per ignotius). Let me explain why this is really problematic:<br /><br />Imagine a statisticalist pointing to their analogies and explanations of evolutionary phenomena and saying, "Evolution isn't mysterious at all, and we have a perfectly good statistical explanation right here. The only causality is in the underlying fundamental physics." The evolutionary causalist is then in the uncomfortable luddite position of insisting, without reason, that we don't understand evolution. Appealing to an analogy with physics that supports the causal position is question begging, if there is no deeper reason why this analogy holds other than it supports the claim that evolutionary phenomena are mysterious and hence causal. Therefore without some other reason to support the causal view of evolutionary phenomena, appealing to mysteriousness does not justify the causalist position.<br /><br />So I don't think your defense of their position is viable, and hence V&H's argument is on shaky ground. Though please feel free to poke holes in what I said.Noahhttp://noahgreenstein.com/wordpressnoreply@blogger.comtag:blogger.com,1999:blog-2814994353835004156.post-86079594937961580302014-05-28T00:12:55.016+01:002014-05-28T00:12:55.016+01:00Thanks for the nice comments Ellen!Thanks for the nice comments Ellen!Christopher Hitchcockhttps://www.blogger.com/profile/10232394766065633104noreply@blogger.com