Friday, November 16, 2012

Darwin's nominalism

"I look at the term 'species' as one arbitrarily given, for the sake of convenience, to a set of individuals closely resembling each other." (Origin of Species).


Does Darwinian theory commit you to nominalism? Logan Paul Gage, in his essay "Can a Thomist be a Darwinist," gives this as a reason why Thomists shouldn't embrace Darwinism.

From God and Evolution (Seattle: Discovery Institute Press, 2010).







18 comments:

Cale B.T. said...

My opinion doesn't count for much, but for those interested in this subject, I'd like to recommend David Oderberg's Real Essentialism. It's not a cheap book, but as a philosophical layman, I've been finding it surprisingly accessible.

rank sophist said...

I'm with Cale: evolution is compatible with Thomism. The conflict is with neo-Darwinism, which claims that all evolution is incremental and non-teleological. Of course, this also contradicts every available scrap of scientific evidence--so it should not be considered an accurate view of the world, in any case. Evolution largely occurs through punctuated equilibrium (speciation events) and epigenetics (quasi-Lamarckism). Natural selection, while important, is after these in significance.

Mr Veale said...

FWIW
Fortunately, evolutionary gradualism does not really imply that species distinctions are illusions. It is true that the differences between parent and viable offspring are likely to be small. Since viable offspring develop from coadapted developmental resources, any major change in those resources is likely to derail development, not generate significant change. However, there is no similar argument against rapid change in population-level properties. Species can quickly go extinct, change their range, change their role in an ecosystem, or change in genetic diversity. These changes occur on ecological rather than geological time scales...So if populations are species by virtue of population-level properties, speciation need not be smooth, gradual, and seamless. Furthermore, the most important contemporary theories identify species and speciation through population-level properties. One well-known approach, the biological species concept, identifies species by asking a question about populations: is this population reproductively isolated? In turn, reproductive isolation is a property of a population, and one it can acquire quickly. A change in the course of a river, a change in pigmentation pattern, or a change in daily activity cycles can cause reproductive isolation.

From Sterelny and Griffiths "Sex and Death: An Introduction to Philosophy of Biology" (Chicago:1999) p182

"...new forms typically arise relatively rapidly (on geological time scales) when lineages divide. Species are born through splits in a lineage and the subsequent reorganization of the fragments, not by the transformation of a whole lineage. If so, then the typical life story of a species involves relatively well defined origins and terminations." ibid p185

"In our view, evolutionary theory lends no support to the idea that our species classifications do not reflect objective features of the livingworld. The division of organisms into species is an objective feature of the living world." ibid, p185

Mr Veale said...

(If anyone is interested, the second part of our response to ECREE is up

http://www.saintsandsceptics.org/when-nothing-is-extraordinary-another-problem-with-ecree/ )

William said...

Cale and rank:

What do you think of the book's attempts to use a neo-Aristotelian classification for micro-organisms? For example, because the system he has separates all life into plant and animal, he places bacteria into either animal or plant kingdoms based on whether they are motile.

Although I am mostly a minimalist not a nominalist about species, to me this forcing of modern knowledge into the bed of Aristotle is a hammer being used to fasten a bolt. You?

BenYachov said...

Is it animal vs plant or animal vs vegetable with Aristotle?

Or to put it another way Sensitive Soul vs mere Vegetative Soul?

Because it seems to me lower lifeforms without any type of Nervous System are default Vegetative regardless of their ability to move or be plants.

Papalinton said...

"The conflict is with neo-Darwinism, which claims that all evolution is incremental and non-teleological." .... "Evolution largely occurs through punctuated equilibrium (speciation events) and epigenetics (quasi-Lamarckism). Natural selection, while important, is after these in significance."

Another misconstrual in the search to inveigle Medieval thought on the back of modern science. There is no either/or dichotomy between 'punctuated equilibrium' and 'evolutionary incrementalism'. Both states are subsumed within the study of evolution and it is a question of relative speed by which natural selection of random mutations occur. Punctuated equilibrium characterises the relatively rapid changes while incrementalism refers to the slow backdrop of change that is constantly occurring in response to environmental conditions. "Stasis", the Gouldian proposition that marks the static period between punctuating events is simply the extra slow period of evolutionary change.

Another misconstrual is that of natural selection being of lesser importance. It is not in competition with the rate of change that distinguishes punctuation and incremental change. Natural selection is the fundamental process that drives both punctuated evolutionary events and incremental evolutionary change.

There is no conflict, only variation in interpreting the evidence that spurs further avenues for continued investigation.

Where conflict arises is in the retrojected proposition that evolution is compatible with Thomism. Who cares? Thomism is entirely irrelevant in, and inconsequential to, the scientific investigation of evolutionary biology. To link Thomism and evolution is simply a means to invoke the highly spurious notion of supernaturalist teleological intentionality. Any such relationship is just an add-on a to mitigate cognitive dissonance.

Papalinton said...

Mr Veale

Sterelny and Griffiths have posited a hypothesis fundamentally based on the notion of population-level and group selection being drivers of speciation change. To say the least, this is a highly contentious proposition for which there is little if any evidence. Where there may be evidence for speciation change within a population the evidence for that change has been equally explained and fits the genetic model of change.

I would ask you to read THIS, just in the interest of review. I would be interested in your opinion.

Mr Veale said...

Hi Papa
I'll take a look at this - but Sterelny and Griffiths do not believe that group selection drives evolution. The quotations I gave might give that impression...but their argument is that properties like "reproductive isolation" belong to groups, not individuals. That does not require group selection.

Have you read Sterelny's -"Dawkins v Gould: Survival of the Fittest"? If not, I think you'd like it.

Mr Veale said...

So - even if a group has a unique history or trait, it does not mean that there was or selection for that trait, or selection of the animals with that trait (or the genes that cause it etc....)

Papalinton said...

I think we are talking across each other a little here:

PapaL: "Sterelny and Griffiths have posited a hypothesis fundamentally based on the notion of population-level and group selection being drivers of speciation change."

Mr V: "I'll take a look at this - but Sterelny and Griffiths do not believe that group selection drives evolution. "

I think it is not so much of Sterelny and Griffiths believing that group selection drives evolution, but rather that population-level group selection drives speciation change. And on the surface of it, that seems a reasonable proposition. But when one digs a little deeper, where they do present illustrations for group selection as evidence indicating a speciation change, those example seem to align closely with gene-level selection at work.

I have just completed reading a very nice piece on Sterelny's -"Dawkins v Gould: Survival of the Fittest" as we speak. It can be read HERE.

And this little piece.

Very interesting, aren't they?

Interestingly, Sterelny works just up the road at the Australian National University, when he's not a Victoria Uni in NZ. He looks a pretty grizzly character. ;o)

Mr Veale said...

LOL, Papa! He does, doesn't he!
Thanks for the links.
BTW Did you know that Sterelny/Griffith is free to read online?
Graham

Chris said...

"Evolution largely occurs through punctuated equilibrium (speciation events) and epigenetics (quasi-Lamarckism). Natural selection, while important, is after these in significance."

This isn't really correct. Punctuated equilibrium isn't an evolutionary force like epigenetics and natural selection; it's a description of the process of rapid change in small populations - changes which are often (always?) caused by high selection pressure. And any epigenetic change must still pass through the selection filter - a creature with an epigenetic novelty is still going to have to survive and reproduce; its descendants will also have to do the same on a statistically high enough level to become a new/separate species.

Crude said...

Punctuated equilibrium isn't an evolutionary force like epigenetics and natural selection; it's a description of the process of rapid change in small populations - changes which are often (always?) caused by high selection pressure.

Not as Darwin envisioned it. Darwin was a proponent of extremely fine-grain gradual, and constant gradualism at that. The idea of periods of evolutionary stasis and sudden, comparatively rapid, incidents of change - not to mention larger changes in the span of a single or short number of generations - wouldn't fit with Darwin's view.

Really, Darwinism as Darwin propounded it is largely dead. Hell, Darwinism as Dawkins saw it isn't doing so hot either.

Contra rank, I'd say any questions of teleology - its presence or lack - has nothing to do with science, and thus with neo-darwinism insofar as it's actually scientific, and not metaphysical speculation.

Chris said...

Well, sure, that's what Darwin thought – in 1859. He didn't know about genetics either. Not terribly relevant at this point. Evolution by natural selection - the most important part of his evolutionary theory - is still by far the dominant paradigm in biology, though there are of course other mechanisms (horizontal gene transfer, genetic drift, etc.) - acknowledged by even the most hardcore neo-Darwinists.

Evolutionary stasis doesn't really contradict gradualism. Stasis just means that outward phenotypic isn't detectable - it doesn't mean that non-fossilizing internal organs aren't changing or that minor genetic mutations that don't have phenotypic effects aren't occurring - mutations are always occurring, in every single generation; most are just infinitesimally minor or completely neutral in regards to selection.

Martin said...

I third Cale B.T.'s suggestion about Oderberg's Real Essentialism. I'm a layman, and it makes for fascinating reading. Especially the chapter on biological species. He addresses all the common criticisms of metaphysical realism that are brought up, such as that the borders between species are blurred, that species aren't fixed, etc.

Crude said...

Evolution by natural selection - the most important part of his evolutionary theory - is still by far the dominant paradigm in biology, though there are of course other mechanisms (horizontal gene transfer, genetic drift, etc.) - acknowledged by even the most hardcore neo-Darwinists.

Whether it's the 'most dominant paradigm' is an open question. I think the most dominant paradigm is something far more broad and general than specific adherence to natural selection being the overwhelmingly most important engine of evolution. Really, my impression is that even defining what natural selection is is a major issue of debate among mainstream biologists.

Evolutionary stasis doesn't really contradict gradualism.

Insofar as it's possible to find some hypothetical interpretation of the results that itself may be impossible to test, it does not. By that standard, next to nothing contradicts young or old earth creationism either.

And stasis isn't the only problem for gradualism. What's happened, however, is that Darwin's strict gradualism has been abandoned, and now gradualism means something closer to 'it took place over time'.

Like I said, Darwin himself is pretty irrelevant at this point. Even guys like Coyne will admit this when their backs are to the wall.

Crude said...

And just to join in, yes, Real Essentialism is a great read for anyone interested in these questions. Lots of ground covered.