Evolution Defended
Not rocket science.
I've been interested in Natural Selection for a long time. I'm with Dennett who thinks that Darwin's idea is one of the most beautiful and powerful ideas ever developed. And of course not everyone agrees. For years I'd meet once a week in a coffee shop with a 'creation scientist' (later morphed to 'intelligent design') for literally years to debate the issue. Our conversation was pretty encyclopedic. Neither of us convinced the other but we each came away way better informed about the issue.
We looked at a lot of things like Paley's idea of finding a watch on a heath and knowing that it had to be designed. It was nothing like a rock or a star. Paley then looked at living things and concluded that there is no way they could have been created by chance. There had to be a designer. This was a plausible thing to say 40 years before Darwin published Origin of Species - but Darwin effectively demonstrated how mindless processes could generate 'design'.
We looked in detail at Behe's idea of 'irreducible complexity' that asserted that complex things like and eye could not possibly arise by Natural Selection because the eye is a complex thing with many components that have to work together for the thing to work at all. The Dawkins demonstrates vividly in Climbing Mount Improbable how eyes have evolved over 40 different times from scratch. This is shown by the fact that there are over 40 different kinds of eyes that have radically different designs. Dawkins also shows a plausible sequence of evolutionary steps that would create an eye from variaton and selection pressure alone.
https://www.theguardian.com/science/2022/jun/28/do-we-need-a-new-theory-of-evolution
Stephen Buranyi
(start quotes)
You may recall the gist from school biology lessons. If a creature with poor eyesight happens to produce offspring with slightly better eyesight, thanks to random mutations, then that tiny bit more vision gives them more chance of survival. The longer they survive, the more chance they have to reproduce and pass on the genes that equipped them with slightly better eyesight. Some of their offspring might, in turn, have better eyesight than their parents, making it likelier that they, too, will reproduce. And so on. Generation by generation, over unfathomably long periods of time, tiny advantages add up. Eventually, after a few hundred million years, you have creatures who can see as well as humans, or cats, or owls.
This is the basic story of evolution, as recounted in countless textbooks and pop-science bestsellers. The problem, according to a growing number of scientists, is that it is absurdly crude and misleading.
And yet, we still do not have a good answer. This classic idea of gradual change, one happy accident at a time, has so far fallen flat.
(aside: well it hasn't actually. That sort of gradual change is still one of the mechanisms driving evolution. Turns out there are others.)
If another force, apart from Natural Selection, could also explain the differences we see between living things, Darwin wrote in On the Origin of Species, his whole theory of life would utterly break down.
If the mutationists were right, instead of a single force governing all biological change, scientists would have to dig deep into the logic of mutation.
Did it work differently on legs and lungs?
Did mutations in frogs work differently to mutations in owls or elephants?
(aside: Natural Selection can have many sources of variation. Mutations happen but are rare because they are generally harmful. More common is the variation caused by gene mixing from sexual reproduction.)
They found that the molecules in our cells - and thus the sequences of the genes behind them - were mutating at a very high rate.
This was unexpected, but not necessarily a threat to mainstream evolutionary theory.
According to the modern synthesis, even if mutations turned out to be common, Natural Selection would, over time, still be the primary cause of change, preserving the useful mutations and junking the useless ones.
But that isn't what was happening. The genes were changing - that is, evolving - but Natural Selection wasn't playing a part. Some genetic changes were being preserved for no reason apart from pure chance.
Natural Selection seemed to be asleep at the wheel.
(aside: It has been well known that there is a lot of stuff in DNA that seems to have no purpose that does't get corrected by DNA's error correcting systems so no surprise that that stuff would change quickly).
(end quotes)
The media needs drama of various sorts to sell stories. With stories about science one of the gimmicks is to claim that each new scientific paper 'overthrows' all that science said in the past.
I've seen it for years with studies of coffee consumption. One study says it's bad for you and another says it's good. Back and forth it goes. The media can't get into the sort of analysis that would place all of this in context because there is no drama there; hence not eyeballs and hence no ad revenue and hence can't be done.
Buranyi's piece quoted above does that. Like, Darwin did speak of gradual change and didn't know the mechanism. He didn't know of genes or dna. But he had observed gradual change and saw that that was enough to account for the variety of nature. Later, mutations were discovered.
Buranyi is like - gasp - Darwin is overthrown! It is found that lots of the material in DNA doesn't seem to have a purpose and changes rapidly. Gasp - Natural Selection is overthrown!
Buranyi should read Dennett. For 30 years now, Dennett, following Dawkins, has shown that Natural Selection is best thought of as an algorithm.
Start with a replicator.
A plant producing seeds that make new plants is a replicator, and the new plant is a replicant. A dog is a replicator, and a puppy is a replicant.
Dawkins makes the point that the idea of replicant and replicator are abstract and don't need to be biological entities. He talked about imitated behavior as fitting that algorithm; called them memes.
The algorithm specifies that there is some variation - that is - the replicants are not exact copies of the replicators.
And the algorithm specifies a selection pressure - that is - some of the replicants are better at being replicators in their turn than others.
And the future gets populated by replicators that inherit the beneficial variation.
This is not rocket science. it's easy to understand. But it's also profound and fundamental.
Natural Selection is quiet about the first replicant. There are many ideas about that but none is conclusive. Which I think is fine. We don't know everything. That doesn't mean that what we do know is wrong.
Buranyi's sensationalist presentation about Natural Selection is normal enough media stuff that I think is more pernicious than the media realizes. These are not just amusing stories. Each story that contradicts earlier stories creates the impression that none of the stories is true.
That is not good.
But I think Buranyi goes further. He brings up arguments that have been debunked for decades (like 'irreducible complexity') that were used by the Intelligent Design (ID) movement that grew out of the Christian 'creation science' movement.
ID was a movement that was actively trying to bring science into disrespect that was disguising its religious roots.
What do think?
I present regular philosophy discussions in a virtual reality called Second Life.
I set a topic and people come as avatars and sit around a virtual table to discuss it.
Each week I write a short essay to set the topic.
I show a selection of them here.