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Evolution Faith

Did Darwin make atheism credible?

Imagine that my wife and I walk into our living room one morning to find that our son’s toy box has fallen over, and pieces of BRIO train set track lie jumbled on the floor. But eight of the pieces are joined together in a perfect circle, lying on the floor, with a train on top of the tracks. My wife asks me: “Did you make that railway?” I say “No – it must have been you”. She says it wasn’t her. We look at each other for a moment, thinking and then we come to two different conclusions.

My wife is worried and says: “Someone must have come into the flat last night. Railways don’t just spontaneously appear from a jumble of fallen pieces. We need to check my jewellery is still there.”

I shake my head and say “This is evidence that there are billions more BRIO sets in the world than anyone has realised. I am going to call a stockbroker and buy some shares in BRIO PLC.”

“Are you crazy?” my wife asks.

“No,” I say. “What do you think the chances are that these pieces could have just fallen like that, and the train fallen on top of them? One in a billion? One in a trillion?”

She says: “Maybe one in a trillion – it just couldn’t have happened by chance.”

I reply: “Yes it could, if there are billions of BRIO train sets in the world that keep being tossed onto the floor. Ours just happens to be the lucky one that has spontaneously formed a perfect circle, with a train placed on top. I had never realised that BRIO train sets are so common. I don’t think anyone had. But here is evidence. There are billions of them.”

My wife would think I was mad. Instead of the obvious explanation of an intelligent agent who has put the railway tracks together, I am invoking pure chance, justified by an outrageous speculation about billions of train sets.

Arguments in ancient Greece

This problem of explaining the origin of complex, purposeful structures by chance rather than by the action of a mind is a problem faced by atheists. In the natural world there are many structures that have multiple parts working together to make higher-order structures that have a purpose. These provide evidence of the work of an intelligent mind. The first philosophers to make arguments favourable to atheism – Leucippus, Democritus and Epicurus, living over 2000 years ago in Greece – were aware of this problem.

The argument for an intelligent mind was made eloquently and persuasively by other Greek philosophers like Socrates and Plato. They drew an analogy between the natural world and human craftsmanship. Look at a statue. No one could deny that a statue is the work of an intelligent mind. How much more is the human body, of which the statue is just a simple representation, the work of an intelligent mind. There must be a supremely intelligent mind behind the natural world around us, and this is the mind of God.

This analogy has been pervasive throughout human history. Hundreds of years later, Jesus Christ said: “Consider the lilies, how they grow: they neither toil nor spin, yet I tell you, even Solomon in all his glory was not arrayed like one of these.” Luke 12:27. He assumed it would be obvious to his listeners that flowering plants displayed more intelligent care than the royal robes of the King of Israel when his kingdom was at peak of cultural innovation. Jesus was making the same analogy between human craftsmanship and the natural world.

All that early proto-atheists like Democritus and Epicurus could say in response to this argument for a mind was that complex, purposeful things in the natural world had just come about by chance. These were just lucky assemblages of atoms. To try to justify this, they said that the universe must be infinitely large and infinitely old, and that there are trillions of worlds within it. We just happen to be the lucky people who are on the stupendously lucky world on which things have happened to come together in such a way that complex life can exist.

Not many people found this a persuasive argument. Even the staunch atheist Richard Dawkins concedes that arguments for atheism in the ancient world were not compelling. “I could not imagine being an atheist at any time before 1859 when Darwin’s Origin of Species was published” he wrote in The Blind Watchmaker.

The case made by Democritus and Epicurus is as ridiculous as my inference of billions of BRIO train sets from the unexpected occurrence of a completed railway in my living room. Needing so much luck to explain the world, atheism did not take off.

This left Socrates argument for design as one of the strongest arguments available to theists down through the centuries. The solar system, the world, the complex life forms on earth – none of these could have happened just by chance. We need the mind of God to explain their design and existence.

As human technology has got more sophisticated over the ages, and we have discovered more about the natural world, analogies have constantly been drawn between the latest human technology and the natural world. The Roman Stoics compared Archimedes’ astronomical mechanism to the workings of the actual stars and planets. William Paley in 18th Century England compared a pocket watch to living things. Today we can compare the latest nanotechnology with the vastly more complex and efficient molecular machines found in every living cell. Or painstakingly written computer programmes with the information encoded in our DNA. The analogy between human craftsmanship and the natural world has cascaded down through the ages, gathering force with technological and scientific progress. It is a persuasive argument for the existence of God.

Darwin according to Dawkins

This argument was fatally undermined when Darwin published The Origin of Species according to atheists like Richard Dawkins. “Darwin made it possible to be an intellectually fulfilled atheist” he claims in The Blind Watchmaker. According to Dawkins, Darwinian natural selection can explain complex life forms without the need to invoke massive strokes of luck; without needing hugely improbably things to happen; without one-in-a-trillion events.

How does it work? Let’s go back to our BRIO analogy. Imagine that instead of just being tipped on the floor once, my sons BRIO set kept being rejumbled every five minutes. Every five minutes there would be a fresh opportunity for bits of track to be joined together by chance. This is a bit like what happens in living things that reproduce. In every new generation there is a new opportunity for new variation.

Now imagine that as well as this rejumbling of the BRIO every five minutes, there is also a rule in place that any bits of track that get joined together do not get rejumbled. They stay as they are. So as soon as two bits are together they stay together. They can wait until by chance a third bit gets added. Then the three bits can wait, and eventually a fourth bit by chance may get added. Eventually the full circle may form, and a train be dumped on top of it. The railway has evolved by a gradual process of cumulative selection.

Step-by-step assembly of a trainset

If you have a system set up like that, then the production of a functional train set does not seem so unlikely. It is a series of unlikely events, but that series does not seen half as unlikely as the spontaneous assembly of the full circle and train in one go. A lot of luck is still involved but not as much as before.

This is the way that Dawkins tries to explain the origin of highly complex things by Darwinian evolution. It relies on small changes that are each selected for, because they provide greater fitness. Gradually they build up something more complicated. It all sounds plausible.

In The Blind Watchmaker, Dawkins suggests that this process could generate something as complex as a human eye. He suggests that an organism could start off with a small light sensitive spot its skin, and gradually over millions of generations this could sink into a little cup in the skin, enabling better assessment of direction. Then it could be enclosed enough to be a pinhole camera. Then it could gain a lens, etcetera etcetera. Painted in broad brush strokes, it all sounds plausible.

But the question we have to ask ourselves is: does this process eliminate enough luck from the origin of the natural world as we know it today for atheism to be credible?

Chance in evolution

In his book The God Delusion Dawkins writes about the Darwinian mechanism of evolution as if it only relies on chance in a very small way. He claims things like this: “Natural selection is a cumulative process which breaks the problem of improbability up into small pieces. Each of the small pieces is slightly improbable, but not prohibitively so” (p. 121, emphasis added). “Natural selection is not only a parsimonious, plausible and elegant solution; it is the only workable alternative to chance that has been suggested” (p. 120, emphasis added). He says that only “somebody who doesn’t understand the first thing about natural selection” would call it a “theory of chance”. He says it is the “opposite”.

I should point out that Dawkins seems to be indulging in a little equivocation here. In one sense what he is saying is absolutely right: natural selection, when narrowly defined, is the opposite of chance. In biology research we often speak of evolution occurring via five forces: natural selection, drift, recombination, migration and mutation. In the context of these five forces, natural selection is the one that is non-random. So as a research biologist, if I superficially read Dawkins’ statements above, I can nod my head and agree.

However, in the context of his book, Dawkins is using “natural selection” in a much wider, more colloquial sense, meaning the whole of the process of the evolutionary process. Used in that sense, it is quite wrong to say it is the “opposite” of chance. In fact, chance is an unavoidable component.

At this point, I could go into a lot of detail about the process of Darwinian evolution, giving you lots of instances where it requires huge injections of luck.

I could write about how evolutionary pathways can get trapped at local fitness peaks that are not global fitness peaks, and can only escape them by random drift. For example, if my BRIO train set had a circle made of eight pieces, which my toy train could happily rotate around, how could I get from that to a more complex train set? I would have to break the circle and insert a junction. I would have to go downhill from a local fitness peak in order to be able to climb a different fitness peak represented by a longer, more sophisticated railway.

To get from the train set on the left to the one on the right, I have to break the circle. Without this backward step, the track cannot progress to greater complexity.

I could write about evolutionary steps that need more than one concurrent mutation to work. To get two mutations in place at the same time that are both required before fitness is increased takes a big stroke of luck.

I could write about new beneficial mutations that simply get unlucky and are eliminated from the population by random drift.

I could write about how some new structures are very likely to need multiple part to come into place at the same time before they can function, and therefore require a lot of luck. For example, what if I had a system where I had to have a circular train set before the assemblage of pieces was selected for? It would take a lot of luck to build the train set. Given the complexity of the molecular machinery of life, it seems hard to imagine that such structures do not exist in biology. (Surprisingly, Dawkins is vehemently opposed to even looking for such things: “searching for particular examples of irreducible complexity is a fundamentally unscientific way to proceed,” he writes in The God Delusion (p. 125). That makes him sound less like a scientist and more like someone views his beliefs as sacrosanct from testing.)

In short, it is very well known to biologists working in the field (and, no doubt, to Dawkins himself) that chance is a very important element in the evolutionary process. But if you read The God Delusion as a non-biologist, you are likely to come away with the impression that it hardly involves any luck at all.

Dawkins’ own invocation of luck

But in reality, I don’t need to make those points. I can grant Dawkins everything he claims for the evolutionary process, and still show from his own admissions that he can’t get away from needing astronomical doses of pure luck to explain how we got here. Atheism has not got away from its problem of an implausible reliance on luck.

Here is a page from Dawkins’ book The God Delusion:

We really need Darwin’s powerful crane to account for the diversity of life on Earth and especially the powerful illusion of design. The origin of life, by contrast, lies outside the reach of that crane, because natural selection cannot proceed without it. Here the anthropic principle comes into its own. We can deal with the unique origin of life by postulating a very large number of planetary opportunities. Once that initial stroke of luck has been granted – and the anthropic principle most decisively grants it to us – natural selection takes over: and natural selection is emphatically not a matter of luck.

Nevertheless, it may be that the origin of life is not the only major gap in the evolutionary story that is bridged by sheer luck, anthropically justified. For example, my colleague Mark Ridley…has suggested that the origin of the eukaryotic cell (our kind of cell with a nucleus and various other complicated features such as mitochondria, which are not present in bacteria) was an even more momentous, difficult and statistically improbable step than the origin of life. The origin of consciousness might be another major gap whose bridging was in the same order of improbability. One-off events like this might be explained by the anthropic principle, along the following lines. There are billions of planets that have developed life at the level of bacteria, but only a fraction of these lifeforms ever made it across the gap to something like the eukaryotic cell. And of these yet smaller fraction managed to cross the later Rubicon to consciousness. If both of these are one-off events, we are not dealing with a ubiquitous and all pervasive process, as we are with ordinary run-of-the-mill biological adaptation. The anthropic principle states that since we are alive, eukaryotic and conscious, our planet has to be one of the intensely rare planets that has bridged all three gaps.

Natural selection works because it is a cumulative one-way street to improvement. It needs some luck to get it started, and the ‘billions of planets’ anthropic principle grants it that luck. Maybe a few later gaps in the evolutionary story also need major infusions of luck, with anthropic justification.

Richard Dawkins (2006) The God Delusion page 140 (emphasis added)

Here, despite his repeated claim that “natural selection is emphatically not a matter of luck”, Dawkins is still reduced to invoking huge amounts of luck to explain how we got here. He is making the same argument as Democritus and Epicurus: he needs so much luck that he has to invoke billions of worlds. He has to posit billions of planets that are potentially habitable by conscious life forms.

Dawkins’ argument is weaker than that of Democritus and Epicurus. They claimed that the universe is infinite in terms of both space and time. But Dawkins knows that the universe has a beginning, so he does not have infinite time to work with. He also knows that it is not infinite in size. This dramatically reduces the probabilistic resources available to him within this universe compared to what Democritus and Epicurus thought they had.

If you read further in The God Delusion, Dawkins also finds himself not just having to invoke billions of habitable planets, but also billions of universes too, to explain why the physical constants of our universe are so fine-tuned for life. Though there is no empirical evidence for multiple universes, it is all Dawkins has to fall back on to give himself the huge amount of luck that he needs to explain reality.

Conclusion

Even if we grant Darwinian evolution all the power for eliminating luck that Dawkins claims for it, atheism is still a huge leap of faith in blind chance. Despite writing: “I could not imagine being an atheist at any time before 1859 when Darwin’s Origin of Species was published”, Dawkins finds himself falling back on arguments made by Democritus and Epicurus in ancient Greece. Dawkins’ ultimate reliance on these ancient invocations of luck undermines his case that Darwin made atheism credible.

Like the ancients, we are still left with a choice between huge amounts of luck, or a divine mind behind the universe and life.

A Professor of Evolutionary Genomics explains why, without God, the appearance of complex life is far too lucky

A Professor of Evolutionary Genomics explains why, without God, the appearance of complex life is far too lucky. Using a BRIO train set.

Posted by Grace Church Greenwich on Friday, 31 January 2020
A talk based on the material in this blog