The IDEA Club’s Punk Eek FAQ

| 11 Comments | 1 TrackBack

In response to postings on The Panda’s Thumb criticizing the IDEA Club’s description of punctuated equilibirum, Casey Luskin invited corrections. I have one or two suggestions. This is not exhaustive; I treat just one aspect of the FAQ.

The IDEA Club description first sets the problem by describing what it represents to be the ‘orthodox’ view of evolution, quoting Gould

Is long, slow, “gradual” evolution (see Figure 1) an inference from the evidence, or was it assumed simply because of naturalism and what was predicted by Darwin’s theory? Gould explains it is inference:

“The extreme rarity of transitional forms in the fossil record persists as the trade secret of paleontology. The evolutionary trees that adorn our textbooks have data only at the tips and nodes of their branches; the rest is inference, however reasonable, not the evidence of fossils.

(Internal quotation referenced to Gould, S. J., “Evolution’s erratic pace,” Natural History, Vol. 86, No. 5, pp.12-16, (May 1977; Emphasis added by Luskin, the author of the description)

This is illustrated by Figure 1. No source is given for Figure 1, so I assume that it is the construction of Luskin, the author of the description.

Language in the description attributes the gently sloping ascents of the lines in Figure 1 to Darwin, using phrases like “Darwin’s predicted slow and gradual evolution” and “Darwin saved his gradual theory of evolution by claiming …”. But Darwin was not, to use Dawkins’ felicitous phrase, a “constant speedist.” In OoS (6th Edition), Darwin wrote:

These several facts accord well with our theory, which includes no fixed law of development, causing all the inhabitants of an area to change abruptly, or simultaneously, or to an equal degree. The process of modification must be slow, and will generally affect only a few species at the same time; for the variability of each species is independent of that of all others. Whether such variations or individual differences as may arise will be accumulated through natural selection in a greater or less degree, thus causing a greater or less amount of permanent modification, will depend on many complex contingencies–on the variations being of a beneficial nature, on the freedom of intercrossing, on the slowly changing physical conditions of the country, on the immigration of new colonists, and on the nature of the other inhabitants with which the varying species come into competition. Hence it is by no means surprising that one species should retain the same identical form much longer than others; or, if changing, should change in a less degree. We find similar relations between the existing inhabitants of distinct countries; for instance, the land-shells and coleopterous insects of Madeira have come to differ considerably from their nearest allies on the continent of Europe, whereas the marine shells and birds have remained unaltered. (p. 291)

There are several references to rates and amounts of change in that one paragraph. Most important is the “no fixed law of development” phrase. While Darwin certainly held evolution to be gradual, in the sense of incremental, he did not hold that evolution proceeded at a constant rate, and in fact discussed some variables he thought would affect evolutionary rates of change.

Compare the IDEA Club figure above with the illustration in OoS:

The IDEA Club Figure gets Darwin’s view of the ‘tree of life’ wrong. In OoS there is just this one illustration, on page 90, which shows Darwin’s conception of a segment (one genus) of the structure of the tree of life, and the IDEA Club Figure misrepresents it. Describing the illustration, Darwin wrote

The accompanying diagram will aid us in understanding this rather perplexing subject. Let A to L represent the species of a genus large in its own country; these species are supposed to resemble each other in unequal degrees, as is so generally the case in nature, and as is represented in the diagram by the letters standing at unequal distances. … The variations are supposed to be extremely slight, but of the most diversified nature; they are not supposed all to appear simultaneously, but often after long intervals of time; nor are they all supposed to endure for equal periods.

[…]

But I must here remark that I do not suppose that the process ever goes on so regularly as is represented in the diagram, though in itself made somewhat irregular, nor that it goes on continuously; it is far more probable that each form remains for long periods unaltered, and then again undergoes modification. Nor do I suppose that the most divergent varieties are invariably preserved; a medium form may often long endure, and may or may not produce more than one modified descendant; for natural selection will always act according to the nature of the places which are either unoccupied or not perfectly occupied by other beings; and this will depend on infinitely complex relations. But as a general rule, the more diversified in structure the descendants from any one species can be rendered, the more places they will be enabled to seize on, and the more their modified progeny will increase. In our diagram the line of succession is broken at regular intervals by small numbered letters marking the successive forms which have become sufficiently distinct to be recorded as varieties. But these breaks are imaginary, and might have been inserted anywhere, after intervals long enough to allow the accumulation of a considerable amount of divergent variation. (pp 90-91, emphasis added)

Nowhere does Darwin succumb to the simplistic notion that evolution proceeds at a slow, gradual, constant rate; he explicitly and repeatedly mentions variation in rates of change. His repeated use of “gradual” and “slow” must be understood in historical context. An important competitor to his view of evolution as the incremental accumulation of favorable variations due to natural selection was saltationism. Even Darwin’s bulldog, Thomas Huxley, believed that large sudden changes from one generation to another were necessary to account for at least some biological change. Darwin firmly resisted saltationism – witness his famous assertion Nature non facit saltum – and he emphasized the incremental nature of evolution in opposition. (See Edward J. Larson, Evolution: The Remarkable History of a Scientific Theory, The Modern Library, 2004, pp. 86-87.) In every case I have found where Darwin uses “gradual” in OoS one could substitute “incremental” with no change in Darwin’s meaning.

Finally, the IDEA Club description has a short section entitled “Is Punctuated Equilibrium a Scientific Theory?” In that section Luskin makes a ludicrous assertion:

But what hard evidence does punctuated equilibrium predict? Macroevolution by punctuated equilibrium predicts that transitional forms will not be found. With respect to finding fossil evidence of the stages of evolutionary change, punctuated equilibrium predicts that evidence of these changes will not be found. (Emphasis added)

That’s complete glop. Punctuated equilibrum makes a very specific prediction about the kind of corroborating evidence it expects, and as Wes Elsberry pointed out (May 27, 2004 01:36 PM posting),

The FAQ claims that PE predicts that no data will be found to support it, yet Eldredge and Gould presented two transitional sequences supporting transitions via PE in their original essay, and cited further examples in their 1977 paper.

I look forward to corrections in the IDEA Club’s Punctuated Equilibrium FAQ.

RBH

Edited 6/1/04 to remove an incorrect reference to extinction.

1 TrackBack

Oh What Tangled Webs They Weave... from Dispatches from the Culture Wars on June 11, 2004 10:12 AM

There are few things quite as amusing as watching ID advocates pretend that ID is not about promoting a particular religious view. It's just fun to see them wiggle and dance when they get caught up in this web of pretend objectivity. A perfect example ... Read More

11 Comments

As historical sidenote, Natura non facit saltum in fact goes back a rather long way. It was used, famously, by Linnaeus, but in fact the originator of the phrase, or something very like it, appears to have been Albertus Magnus, the teacher of Thomas Aquinas.

It did not mean gradual change. At the time, it was not thought that things changed much over time - the world was as full of as many things as it could be (and we should all be, as the nursery rhyme has it, as happy as kings because of it), and not much more could be created now.

Instead, it meant that forms gradually merge into one another when arranged logically. This was later called the lex continua by Leibniz, and E. O. Lovejoy, the great historian of ideas who baptised the Great Chain of Being from which this comes, called it the Principle of Plenitude.

Bonnet organised all species in a single scale, and Lamarck made that scale into a temporal sequence. By the time Darwin adopted the saying, it was understood that there were intermediate forms between related groups nearly all the time, and so his adoption was merely the claim that things were related on a continuum, but not that things changed all the time in a constant and gradual manner, as you indicate here.

Many thanks for the historical development, John.

I depended on Larson’s usage, in which he represents Darwin’s meaning as “Yet he [Darwin] believed that both some variations (whatever their cause) are inheritable and (quoting the Latin maxim “Natura non facit saltum,” or “Nature makes no jumps”) that all inheritable variations are, as he characterized them, “infinitesmally small.” Attuned to discontinuities in the fossil record and perceiving no reason for limiting the size of variations, Huxley favored the so-called “saltationist” position that evolution proceeded in jumps through the inheritance of gross mutations” (Larson, Evolution, pp. 86-87).

My main point is that it seems clear from OoS that Darwin did not envisage evolution, whatever the source of variation, to be a constant rate phenomenon. Granted, he by and large appears to assume a sort of sympatric speciation, with offspring species replacing parent species, though he did propose that intermediate forms existed in lesser numbers than the parent population (OoS, 6th Edition, p. 136). He also implicated geographical isolation (e.g., p 84), and even what amounts to coevolution (also on p. 84).

So your remark is directly on point: Darwin did not suggest either continuous or constant rate evolutionary change.

RBH

Question by Sergei: “Dr. Ratzsch, what experimentally verifiable predictions does ID theory make and what experimental methodology would you advocate to test these predictions?”

answer by Del Ratzsch: “Sergei - That is certainly a key question and one which, it seems to me, the future fortunes of ID theory may hang upon. However, the question itself is not so simple as it may appear.

As I argued in NDS, what it is or is not legitimate to demand of some comnponent of science depends upon exactly where in the scientific conceptual hierarchy it operates. And the same may apply to design.”

Doesn’t that part just say it all? 1) Well, that’s an important question 2) Uh…maybe we don’t have to have much?

It looks to me like he was setting up for some kind of Alvin Plantinga idiocy where you say that god is ‘properly basic’, therefore you don’t have to have any reason to believe, you just can.

They’ve got nothing. ID will never mean anything to science, except as an amusing distraction, but it’s a shame that it’s going to waste a lot of people’s time in the political and educational spheres.

“Lost time is never found again.” –Benjamin Franklin

I was wondering if anyone has ever seen criticism of Punk Eek which actually cites the fossil evidence provided by Eldredge and Gould and then goes on to attack that evidence?

Although the IDC-ers will say that it only amounts to microevolution and not macroevolution (a distinction without a difference), Lenski’s experiments showed that the rate of new phenotypes appearing in his E. coli cultures was distinctly step-like. In other words the data fit the model of punctuated equilibrium (and he in fact used the term).

Frank Schmidt Wrote:

[…] Lenski’s experiments showed that the rate of new phenotypes appearing in his E. coli cultures was distinctly step-like. In other words the data fit the model of punctuated equilibrium (and he in fact used the term).

Although Lenski may have used the term “punctuated equilibrium”, it seems more likely to me that he simply referred to a series of selective sweeps separated by comparatively uneventful periods. By contrast, Gould & Eldredge had something more specific in mind. Punctuated equilibrium is a hypothesis explictly about speciation, and it says that all directed evolutionary change occurs during cladogenesis and that anagenetic evolution is just a random walk. If Lenski demonstrated significant anagenetic evolution then this is a point against punctuated equilibrium.

Casey Luskin has posted a response to my remarks above. I’ll make just one or two comments on that response.

Regarding gradualism in evolution, Luskin quotes Gould to the effect that Darwin really was a gradualist in spite of Darwin referring repeatedly to variations in rates of evolutionary change. Well, Darwin really was an incrementalist, which is not quite the same thing as a gradualist. Gould also exaggerates (by implication) Darwin’s commitment to a constant rate model, I think. Darwin clearly held to one-small-step-at-a-time evolution, but equally clearly knew that evolution could negotiate those small steps rapidly or slowly, and described some of the variables he thought would influence the rate. By no means do I mean to argue that Darwin was “the father of punctuated equilibrium,” as Gould puts it, but neither do I think ignoring Darwin’s very clear remarks about varying rates of change is a fair representation. Darwin had a better handle on the dynamics of evolution than Gould (or Luskin) gives him credit for. Not incidentally, Gould was also an incrementalist.

Luskin responded to my comment about the FAQ’s treatment of evidence for PE by saying

In fact, Hoppe fails to quote my subsequent sentence where I write “The theory of punctuated equilibrium may still predict certain patterns which may be found in the fossil record…”. (RBH italics)

“May” is a weasel word in this context, since Eldredge and Gould made quite specific statements about the nature of the evidence that would speak to PE and they described specific instances that fit. There’s no “may” about it. PE does predict certain patterns, and they are found in the geological conditions Eldredge and Gould said they would be found.

There is a pervasive conflation of time scales in the IDEA Club FAQ that is compounded in Luskin’s response. Eldredge and Gould were at pains to distinguish between geological and biological time scales; that is a significant component of their work. Luskin provides four quotations from Gould that make that quite clear. In three of Luskins’ four quotations Gould refers specifically to that issue and to the implications of being forced to use sediments deposited on a geological time scale for the kind of fossil evidence that will be available to be found. Luskin writes of this that

Thus transitional forms are not to be normally expected under Punc Eq and I don’t think I was wrong to say that. But, evidence can be found to support punc eq. As I already noted, I cited to some of this data in support punc eq: the sort of rapidly changing lineages which Gould and Eldredge cite in their 1977 paper (see ref 17 of the Punc Eq article for details). Gould writes that, “the persistence of ancestors following the abrupt appearance of a descendant is the surest sign of punctuated equilibrium.” … But the abrupt appearance of biological novelty is also exactly what one would expect if an intelligent agent had rapidly infused large amounts of genetic information into the biosphere. Thus, in my opinion, punc eq is untestable when it comes to distinguishing between it, and intelligent design theory.

Does Luskin mean to suggest that the infusion of “large amounts of genetic information” by an intelligent agent occurs on the biological time scale that PE invokes (i.e., thousands to tens of thousands of years/generations)? Are we to take ID as the default whenever specific evidence of the sort Eldredge and Gould described is not currrently available? If so, Luskin is back to an intelligent designer of the gaps argument: PE operated (via Darwinian processes) wherever we have specific evidence of a transitional series of the sort PE predicts; ID is the case whenever we don’t. Once again, though, there’s no independent evidence for intelligent design.

Luskins’ confusion of time scales is essential to the creationist misuse of PE. I have not previously heard that putative intelligent designers infuse genetic information into the world on biological time scales spanning thousands of generations. Luskins’ assertion that PE and ID are empirically indistinguishable depends on the confusion of time scales. Does intelligent design creationism really predict that “genetic information” is infused into the biosphere over thousands to tens of thousands of generations?

Luskin writes

I’m not going to give more examples that Gould and Eldredge cite because it would just be redundant. Suffice to say, they find plenty of examples of abrupt appearance of new species in the fossil record. As an ID proponent I welcome this sort of evidence, because it usually involves the abrupt appearance of novel morphologies which is utterly consistent with intelligent design theory.

But to be consistent with Gould’s view, one has to preface each “abrupt” in that passage with “geologically.” Once again, does ID operate in biological time? PE does.

Finally, Luskin tells us he has changed the wording in the FAQ to read

But what hard evidence does punctuated equilibrium predict? With respect to finding fossil evidence of the transitional stages of evolutionary change, punctuated equilibrium predicts that direct fossil evidence of transitional morphologies will tend to not be found. (italicized words are new)

That’s still a misrepresentation. A more accurate representation would read something like “PE predicts that direct fossil evidence of transitional morphologies will be found rarely, and then under specific geological conditions.” PE’s prediction is not of a negative, it’s a conditional affirmative prediction: ‘Under specific geological circumstances one has a fighting chance of finding direct evidence, but not under other geological circumstances.’

RBH

Regarding Lenski’s claim for “punctuated equilibrium” in his cultures: that’s really a misuse of the term, and was a poor choice of words. As Erik said, the data fit a model of selected sweeps in a population not limited by mutation rate. The “punctuations” are simply the relatively small time spans that it takes for a more fit genotype to go from being about 10% of a population to about 90% of the population.

Board Managers,

Porn alert!!! Delete Post# 4395 and cancel Johny Hobson’s membership.

Luskin states,

Thus, in my opinion, punc eq is untestable when it comes to distinguishing between it, and intelligent design theory.

That’s just bizzare. It’s also impossible to distinguish between punk-eek and the “fossils are made by satan theory”, but barring any independent evidence for the latter, it’s not even a consideration.

Jason,

Luskin is just doing Dembskian wordsmithing. What I think he really meant is:

“Thus, in my opinion, intelligent design ‘theory’ is untestable when it comes to distinguishing between it, and punc eq - or anything else for that matter.”

Remember that it was William Dembski himself who said that ID could accommodate all the results of “Darwinism.”

About this Entry

This page contains a single entry by Richard B. Hoppe published on May 30, 2004 4:13 PM.

Adventures of the Wedge: Synchronicity was the previous entry in this blog.

Some Facts about Motives - for Paul Nesselroade is the next entry in this blog.

Find recent content on the main index or look in the archives to find all content.

Categories

Archives

Author Archives

Powered by Movable Type 4.361

Site Meter