Monday, 30 May 2016

Evolution revolutions compared

I've been promoting an evolution revolution over the past decade. The main theme is an expansion of the domain of evolutionary theory. The main proposed title is Universal Darwinism.

The extent to which this is a revolution has been debated. I think it is the biggest scientific revolution I have seen and the most interesting revolution that is currently going on.

Recently, other evolution revolutionaries have been making the headlines with their own evolution revolution. In particular, I'm thinking of the extended evolutionary synthesis. Since the proponents of this recently landed an 8 million dollar Templeton Foundation grant to pursue their ideas, we will probably be hearing more from them in the future.

The proponents of the "extended evolutionary synthesis seem to want to play down the revolutionary aspects of their proposals, but their proposed revolution has a number of things in common with the ideas I promote - so it seems appropriate to compare them.

At first glance their proposals are oriented around incorporating developmental biology into evolutionary theory. I recognize that developmental biology was left out of the modern evolutionary synthesis, but I wouldn't say that the focus of Universal Darwinism was putting it back in. This difference in perspectives gives our proposals a rather different slant.

One thing they do argue for is "Inclusive inheritance". They say:

The EES recognizes that inheritance results not just from genes but also through the transmission of a wide variety of resources (epigenetic marks, antibodies, hormones, symbionts, behavior, environmental states), through which parents construct developmental environments for their offspring. In the EES, heredity and development are closely intertwined and can include all causal mechanisms by which offspring come to resemble their parents."
IMO, this is the part of their proposal that most closely resembles Universal Darwinism. Universal Darwinism points out that copying operations are ubiquitous in nature, and are not confined to biology. High fidelity copying is also common. My main comment on their presentation is that it clearly does not go far enough. In particular, I see no sign of Darwinian physics in their presentation.

To their credit the proponents do extend inheritance beyond DNA and culture. They criticize 'dual inheritance' models of cultural evolution as ignoring other kinds of environmental inheritance and propose their own 'triple inheritance' models which don't have this defect. This material is all good and correct.

In Universal Darwinism, it isn't just inheritance that is "extended". It's all the operations found in more conventional evolutionary theory: copying, mutation, selection, filtering, sorting and merging. Do the proponents of the extended evolutionary synthesis recognize this? To some extent they do. Their presentation of this idea seems a bit odd to me, though. What they emphasize is what they call "multiple routes to the adaptive fit between organisms and environments". The basic idea here is that rather than just organisms adapting to environments, organisms change environments to suit themselves. Since they have organisms selecting environments as well as environments selecting organisms, this seems like a bit of an expansion of selection - compared with the conventional role of selection in evolutionary theory. However, this idea too seems watered down compared to the presentation typically found in Universal Darwinism.

I've previously commented about their terminology. They use the term "niche construction" use a lot, but have a confusing and counter-intuitive definition of it. According to them "niche construction" involves any change made by an organism to its environment. That mixes together niche creation and niche destruction. In my opinion, referring to destructive operations as "construction" gets confusing fast. I call their concept "environmental modification by organisms". I don't think it is important enough to deserve a snappier title. Things like "environmental modification", "niche creation" and "niche destruction" seem like better terminology to me.

They frequently use the term ecological inheritance. By contrast I more frequently use the term "environmental inheritance". I don't pretend these terms are synonyms, but they do represent competing terminology. Ecological inheritance seems like an umbrella term that includes organic inheritance. Environmental inheritance excludes organic inheritance. So we have Ecological inheritance = Organic inheritance + Environmental inheritance. It's nice to have an umbrella term, but IMO, usually what you want is something that contrasts with organic inheritance - not something that includes it.

I'm also concerned that their more revolutionary content is mixed up with a lot of more conventional material that will be regarded as being old hat.

Maybe there are some good things in their proposal that I'm currently missing, but my impression is that this is a watered down and inferior evolution revolution - when compared to the Universal Darwinism that I have been promoting. In fact, my reaction to their proposals has been similar to when I first read about Boyd and Richerson's version of cultural evolution. I felt as though the revolutionary content in memetics had been watered-down and stripped out, leaving a rather dry and boring husk. Perhaps watered-down content is all that academia is likely to stomach - but I want evolutionary theory to skip ahead a bit. The evolution revolution has already been going on for 150 years. How much longer is it going to take?


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