Non-creationist, non-Darwinist, "third way" theories of evolution.
Challenge to purely physical mechanisms of evolution
- Written by Shaun Johnston Shaun Johnston
- Published: December 24, 2020 December 24, 2020
- Hits: 761 761
I see the past four centuries as having introduced us to two major scientific revolutions. However, I see the first of these revolutions, involving the physical sciences, having distracted us from exploring the second, involving how we evolved, holding us back from extracting wisdom from it. How might we get access to that wisdom?
The second revolution was announced in 1794 in Zoonomia by Erasmus Darwin, Charles Darwin’s grandfather. Erasmus outlined all the theories of evolution later picked up and developed by Lamarck, Robert Chambers (“Vestiges”) and his grandson Charles (natural selection). But a fourth has lain dormant. Here it is:
"… in the great length of time, since the earth began to exist…would it be too bold to imagine:
- all warm-blooded animals have arisen from one living filament
- possessing the faculty of continuing to improve by its own inherent activity,
- delivering down those improvements by generation to its posterity."
Today his “living filament” seems an astonishingly accurate prediction of something that wouldn’t be discovered for another two centuries, the genome. In effect Erasmus is asking, could the genome be the agent that, “by its own inherent activity,” drives evolution? Up to now, all that’s been available to support evolution since life began has appeared to be the physical environment. But Erasmus reminds us that the genome too has been a constant presence throughout evolution and, unlike the material world, as evolved creatures changed so did their genomes.
To allow for taking Erasmus’ suggestion seriously I challenge two assertions coming out of the first revolution.
- Physical determinism: all events occur as determined by the laws of physics.
- Mechanisms of evolution are purely physical.
Here’s my reasoning: Experience tells us that consciousness and brain can communicate with one another in both directions. For example, there’s no aspect of conscious experience I can’t decide to write about, that I can’t make my brain give physical expression to. If my brain can respond to that decision and report what I’m conscious of, I see no reason to doubt it can respond to any other decisions I arrive at consciously. For example, I can decide I want to know more about consciousness itself and make my body order a book about it. Such experiences persuade me that body and mind can work together as one. And, for this capability to have evolved, I conclude, brain and mind must surely have evolved together, as a single capability or set of adaptations. For that to have happened, human physical bodies and consciousnesses must be able to take on some combined form that can evolve as one. So in terms of both our conscious experiences and how evolution progresses, brain and mind appear to make up a single entity.
Physicalists account for this by making mind merely another rendering of the purely-physical brain. Us having any kind of volition independent of physical laws they say can only be an illusion. I understand there are some people, “aphants,” who don’t have a mind’s eye and aren’t aware of arriving at decisions consciously (see “my girlfriend has no inner monologue” on youtube.com) and I can see why they would deny experience consciousness any independent existence.
I see a way around this objection. It has to do with the creation of novelty over the course of evolution. Mars and the moon appear to be purely physical. They display very little evidence of novelty, no more than you’d expect on a purely-physical body. But on the Earth novelty abounds, in the form of species of living creatures. Could that be due to purely physically-deterministic processes or does it indicate there are other kinds of processes at work?
I think this is open to study. At the end of this paper I suggest how to do that. When I apply this to the combination of genetic mutation and natural selection it falls hopelessly short.
In such a situation, what is it reasonable to do? What I did was, I looked elsewhere for clues to what the mechanism of evolution could be. I got a clue from our ability to create novelty, in engineering and architecture for example. New designs do not seem to arise initially from physical forces acting on prior designs, but consciously, creatively, in human minds. If we assume this capability evolved, that tells us the processes of evolution can engage both physical processes and processes of consciousness.
And where might this creative agent of evolution be lodged? I will follow Erasmus Darwin and suppose it to be lodged in the genome.
This conclusion is radical enough to amount to a second scientific revolution. I think it offers us wisdom of two kinds. First, it suggests we’ll find far more wisdom within us than we’re likely to expect if we limit ourselves to having evolved through a purely physical process. Second, it suggests we can find wisdom in the natural world, by how the processes of evolution manifest themselves creatively in the capabilities of living creatures.
APPENDIX. Method for assessing if a purely physical mechanisms such as genetic mutation plus natural selection could account for the evolution of an interbreeding human population of one million individuals in the one million years during which its evolution occurred most rapidly.
Estimate the capability of that mechanism:
- If generation length is 20 years, one million years corresponds to 50,000 generations.
- If for the efficiency of natural selection we use the 1% Ronald Fisher used in his equations that the modern synthesis got based on, the effective number of generations is 5000.
- If you allow each woman to have had, say, eight progeny of which only two survive, then natural selection gets to select for changes among 3 billion nucleotides by rejecting only three progeny out of every four.
- From these data in this population ( taking into account the order in which they would be needed, see below) calculate how many particular changes to genes natural selection could select for.
Estimate what has to be accounted for:
- Estimate how many changes to the chromosome must have occurred and become widespread to account for rapid evolution of characteristics in that population in one million years. Include consideration of changes in development from embryo to adult. Allow also for continued selection of existing characteristics to prevent their loss through disuse.
- Estimate how many beneficial mutations to our genome that many changes would require, taking into account the order in which they’d be needed. Given that random damage to a blueprint if more likely to be harmful than beneficial, for each beneficial mutation allow a corresponding, say, one hundred harmful but not fatal mutations, that make equal but opposite contributions to fitness. Given Fisher’s efficiency for natural selection of 1%, confirm that overall fitness rises as both beneficial and harmful mutations accumulate generation by generation.
I've treated this at greater length in "Are You Wonderful? Good Science Says, Yes." (Amazon)
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