Skyhooks and cranes-9: The resurgence of natural selection and the resurgence of religion

(For other posts in this series, see here.)

I am going to conclude this series by arguing that it was more-or-less a coincidence that led to the deep-seated animosity towards evolutionary theory in America.

The early 20th century was the time when religious people in America became alarmed that they had perhaps gone too far in separating church and state in the public schools and decided to try and reverse the trend, and this movement coincided in time with the rise in acceptance of natural selection as the mechanism evolution. This theory, with its explicit rejection of a special divine plan for the human race, became seen as a potent symbol of an anti-religious way of thinking that had to be combated. Hence it was natural to use opposition to the teaching of the theory of evolution as a vanguard action that would lead to the restoration of religious instruction in schools.
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Skyhooks and cranes-8: Alternatives to natural selection

(For other posts in this series, see here.)

In the half century after Charles Darwin published his On the Origin of Species in 1859, the idea of evolution gained considerable ground but the theory of natural selection was just one of several mechanisms that drove the process, and hence the anti-religious implications of the theory were somewhat muted.

Some of these alternative theories were modified forms of Lamarckism, the idea that characteristics that an organism acquired during its lifetime that enabled it to survive better were somehow transmitted to the entities in the body that carried inherited traits to their progeny, so that children inherited that acquired trait. These changes could either come about because of animals needing or desiring a change (the famous Lamarckian example of giraffes getting longer and longer necks as a result of having to strain to reach high leaves) or the ‘use-disuse’ theory, that body features that people used a lot would grow and become more common while those that they did not need or use would atrophy and disappear (the example here being the building of certain muscles in the body or the disappearance of fish-like features once they became land animals).

The difference between use-disuse theory and natural selection is subtle but important. In use-disuse theory, if an organism does not use some property, that property gets diminished in its offspring. So a parent who does not exercise is more likely to have children who are not athletic, because the parent did not exercise. In natural selection, on the other hand, it is the variations in genes that result in variations in the properties of organisms and those organisms that have features that provide a selection advantage are more likely to survive to adulthood and to parent offspring. Hence those genes tend to increase in the population. So whether a child has good eyesight or not depends (at least to some extent) on the parents’ genes and not on the parents’ lifestyle, except insofar as the parents’ lifestyle influences the child’s lifestyle.

Another alternative to natural selection was the theory of orthogenesis, that suggested that evolution followed a path determined by forces originating within the organisms themselves. This made it possible to think that the laws of evolution contained within them forces that guaranteed the eventual emergence of the human species.

The alternative theories such as use-disuse and orthogenesis had the reassuring feature that there was some sort of deliberate and directed progression in evolution, enabling their believers to still think of human beings as special and as the pre-ordained end point of the process. The idea that human beings were special in the eyes of god could thus be retained, giving religious believers the comfort that their lives had the external meaning that they sought.

The theory of evolution by natural selection offered no such assurances. But in the second half of the 19th century, even after the publication of Darwin’s famous book On the Origin of Species in 1859, this disturbing idea was in the background. In fact, by the end of the 19th century, the theory of natural selection (though not evolution as a whole) seemed to be in full retreat.

The year 1900 saw the rediscovery of Gregor Mendel’s 1865 work on genetics. We now realize that this discovery removed one of the major objections to the acceptance of the theory of natural selection, which was the idea that children were thought to have the average properties of their two parents, so that even if one organism developed a favorable feature, that feature would become diluted in the next generation because that organism would most likely mate with another organism that did not have the favorable feature. There did not seem to be a good way for a positive feature to steadily increase from generation to generation in small incremental steps, the way that natural selection postulated. Mendel’s theory allowed changes to remain in the population without getting diluted by mating.

But the implications of Mendel’s work were initially misunderstood and theory was thought to work against Darwinian natural selection, further hastening its decline in importance. As a result of all these factors, the idea of natural selection as the fundamental mechanism for the evolutionary process went into an even greater period of decline that continued into the early years of the 20th century, even as the fact of evolution was increasingly accepted. (Peter J. Bowler, The Eclipse of Darwinism, 1983)

But beginning around 1910, the emergence of the new field of population genetics that correctly coupled Darwinian natural selection with Mendelian genetics, created what is now called the neo-Darwinian synthesis. The mathematical analyses of scientists such as J. B. S. Haldane, Sewall Wright, and R. A. Fisher put natural selection on a solid theoretical footing and led to the resurgence of that idea as the prime mechanism for evolution. By around 1920, the reversal was complete. Darwin’s theory of natural selection was ascendant and has remained so ever since, growing even stronger with time. (William B. Provine, The Origins of Theoretical Population Genetics, 2001).

But one consequence of this dominance was that the idea that human beings were somehow designed by god, and that the process of evolution was somehow guided to eventually produce them, was seen as incompatible with science. The idea that humans had a special purpose was no longer seen as credible.

Meanwhile, we saw that up through the end of the 19th century, there had been a consensus that it was good to keep religion and the state separate, and the use of religious teaching and prayers and the Bible in public schools had been steadily declining. But around the turn of the century, there were increased rumblings that perhaps this had been carried too far and efforts were made to restore the balance. And the start of the 20th century saw the beginnings of a push to bring back the Bible and religion into public schools.

This renewed interest in putting religion back in schools happened to coincide with the resurgence of natural selection and is, I believe, the reason that the US has had this seemingly unique obsession with, and hostility towards, the theory of evolution by natural selection.

Next: The resurgence of natural selection and the resurgence of religion.


Some time ago, I expressed my sense of frustration with the literary output of writers like James Joyce and William Faulkner for seemingly going out of their way to make their works difficult. The comic strip Pearls Before Swine seems to take a similarly dim view.

Skyhooks and cranes-7: Early American reactions to evolution

(For other posts in this series, see here.)

The original question that started this series was why there is such deep-seated and long-standing hostility to Darwin’s theory of evolution, especially in America. It is one that I am often asked and is not a question that can be answered briefly.

As I have suggested, part of the reason could be that the fact that even the human mind and consciousness may not be anything special but are the products of the working of the mindless natural selection algorithm and following the same natural laws is disturbing to some. Evolution, properly understood, rules out any non-material cause for the properties of living things, and this can be disturbing to religious and non-religious people alike who want to cling on to the romantic idea that humans are somehow special or that there is something transcendent that cannot be explained in terms of natural laws.
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Skyhooks and cranes-6: Why some atheist scientists support the morality skyhook

(For other posts in this series, see here.)

One can understand why the Pope and religious scientists want to promote the unsustainable idea that the world of morality and ethics lies in a separate domain outside the reach of scientific investigation and accessible only by religion. But what is puzzling is why so many nonbelievers, including scientists, also seem willing to give credence to religion the role of sole arbiter of morality and ethics.
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Skyhooks and cranes-5: Darwin and morality

(For other posts in this series, see here.)

The final skyhook that is invoked is the one of morality. It is argued by some religious apologists that we cannot explain the universality of some ideas of right or wrong or the existence of altruism, without invoking something transcendent, some cosmic conscience. Francis Collins, former director of the Human Genome Project and of the National Human Genome Research Institute at the National Institutes of Health and author of the book The Language of God, elevates this idea to something he calls the Law of Human Nature and is a strong exponent of this skyhook. To do so, he has to make the self-serving and unsubstantiated assumption that human nature is not only unexplained, it is fundamentally mysterious and inexplicable, thus requiring a skyhook and thereby foreshadowing his conclusion.
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Skyhooks and cranes-4: Understanding the mind

(For other posts in this series, see here.)

Currently people seem to be pinning their hopes for a skyhook on the workings of the human mind. This is not because the case here is stronger. In fact, there is no reason whatsoever to think that science cannot explain how the mind works because, unlike with origins of the universe, there are no extraordinary circumstances involved. There is every reason to think that the laws of science that apply outside the brain, and which we can study carefully under controlled conditions, also apply within the brain. There is no reason to suspect that there is anything more to the mind than brain activity.
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Skyhooks and cranes-3: The last four skyhooks

(For other posts in this series, see here.)

Some people simply cannot get over their childhood infatuation with magical thinking. They want and need to believe in skyhooks. They do not want science to fill in all the gaps in our knowledge. They want there to be some gap that they can only plug god into. Or as the TV character House says, “You know, I get it that people are just looking for a way to fill the holes. But they want the holes. They want to live in the holes. And they go nuts when someone else pours dirt in their holes. Climb out of your holes, people!”
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Skyhooks and cranes-2: Replacing skyhooks with cranes

(For other posts in this series, see here.)

Darwin’s big idea of natural selection essentially removed the necessity for skyhooks. According to natural selection, complex things could and did emerge from simpler things and hence we no longer need to invoke skyhooks to explain how they came about. Instead we now have ‘cranes’ that can do all the lifting we need.

Daniel Dennett in Darwin’s Dangerous Idea (1995) uses the metaphor of the cranes used in building construction to contrast with skyhooks. Cranes are devices that can lift things, just like skyhooks can, but they are not magical devices that suddenly appear out of the sky. They are real, we know how they are built and where they come from, and they are planted on solid ground. Furthermore, small cranes can be used to build bigger cranes that can in turn be used to build yet bigger cranes and so on, until we end up with some really powerful cranes that can do amazing and, to the untrained and unobservant eye, may appear to be skyhooks and do seemingly magical things. But the wonderful thing is that they come about naturally.

Dennett argues that in the evolution context, cranes are natural processes that speed up the process. Starting with the simple and basic process of natural selection, increasingly sophisticated organisms have appeared over time that act like cranes, enabling even more complex life forms to be created even more quickly. In other words, we have evolutionary cranes creating even bigger, more efficient evolutionary cranes.

For example, the evolution of DNA likely started with point mutations at single locations. But once that produced organisms that were capable of reproducing sexually, the process of gene swapping that occurs during the process of meiosis (by which the sex cells that contribute to reproduction are created in the testes and ovaries) has led to much faster genetic changes and more rapid evolution than could be obtained using point mutations alone. So sexual reproduction is a powerful evolutionary crane.

Natural selection favors those systems that can evolve faster because they are more adaptable to changes in the environment, so that the rate of change of systems increases with time. In other words, evolution speeds up. Massimo Pagliucci suggests that “natural selection may favor the evolution of particular molecules (called “capacitors” of evolution), or arrangements of gene networks, that make it easier for a population to evolve in response to new environmental changes.”

All these processes eventually resulted in the emergence of human beings who have language and science and technology and thus can be considered as yet more powerful cranes because we are now able, through our ability to significantly control our environment and with genetic engineering technology, to create new organisms that would have taken a long time to come about by themselves without our presence.

Thus we humans are not only the product of work done by other cranes, we ourselves serve as cranes for future development. As Dennett says:

Vast distances have been traversed since the dawn of life with the earliest, simplest self-replicating entities, spreading outward (diversity) and upward (excellence). Darwin has offered us an account of the crudest, most rudimentary, stupidest imaginable lifting process – the wedge of natural selection. By taking tiny – the tiniest possible – steps, this process can gradually, over eons, traverse these huge distances. Or so he claims. At no point would anything miraculous – from on high – be needed. Each step has been accomplished by brute, mechanical, algorithmic climbing, from the base already built by the efforts of earlier climbing. (p. 75)

To me this is an amazing and exciting thing to conceive, that we have the power to explain life without invoking skyhooks, if not in all its details now, at least in principle. But not everyone shares this sense of excitement at the ever-increasing explanatory power of science. In particular, many people (and not all of them are religious) are uneasy about the idea that we humans, with all our sophistication, are also simply the end products of this mechanical algorithmic process. They simply can’t wrap their minds around the idea that there is nothing at all, no vital essence or soul, that is unique and makes us human, not even our minds or our consciousness or our sense of morality. While we have some qualities (like language) that distinguish us (at least partially) from other species, there is not a single thing that we humans possess that could not have come about through the same algorithmic processes that also produced slugs or worms or a leaf.

This can be hard to take for those who have a sense of superiority about the human species. Darwin’s theory so completely undercuts the basis for believing that humans are possessed of some quality that is not the product of the Darwinian algorithm that it distresses people and many have tried to find ways to suggest that it is incomplete. As Steven Pinker says, “People desperately want Darwin to be wrong . . . because natural selection implies there is no plan to the universe, including human nature.” (Steven Pinker, How the Mind Works (1997), p. 165)

Next: The intelligent design skyhook

POST SCRIPT: From bacteria to humans in four minutes

In the space of four minutes, Richard Dawkins gives an overview of the sweep of evolution from bacteria to our common ancestors with apes.

Skyhooks and cranes-1: Why skyhooks are appealing

I occasionally meet people who, knowing something about my interests with science and religion, say something like “I am not religious but I am skeptical of the theory of evolution.” These people are often well-educated but not biologists or archeologists or paleontologists or anthropologists, so it is unlikely that they have done any kind of scholarly study of the evidence in favor of evolution and found it wanting. Their skepticism of evolution seems to spring from a different well.

When questioned, it usually turns out that the major reason for their doubts is that we live in a world that has an amazing array of diverse and complex organisms. If one doesn’t closely into the science and mathematics of evolutionary theory, it can seem quite incredible that all this could have emerged by purely natural causes. So for some people, skepticism about evolution arises purely from a sense, a gut feeling if you will, that it is highly unlikely that life arose in the unguided way that evolution proposes. Just last week I had a discussion with a professor of chemistry who argued in precisely this way, that he could not imagine that all this could have come about without some kind of guiding intelligence, and what could that be but a supernatural agency of some kind?

I have argued before that evolution by natural selection, though unguided, is very far from something that happens purely by chance. While it is chance that produces the variations, the process of natural selection is highly focused. Furthermore, people’s intuitions about probability are notoriously poor, and people should be wary of placing too much weight on them.

The other major source of discomfort is that people cannot properly conceive of very long timescales, especially the hundreds of millions of years that are involved in evolutionary processes. Things that are unlikely over shorter time periods can become likely, even inevitable, if you wait long enough, but people have no real feel for that. For example, we all know that the chance of winning a big lottery prize is very small. But if I were willing to play for a very, very long time, the probability of my winning becomes very high, almost inevitable. But of course, the amount I would have bet would be almost certainly be much more than my winnings and I would be long since dead anyway, so the whole exercise would be pointless. But our tendency is to take the probability over our short lifetimes, and erroneously assume it remains the same over very long time scales.

But even allowing for that, there is something strange about the theory of evolution being singled out for skepticism. After all, all manner of small probabilities and long time scales are involved in the Big Bang theory, involving the way that the primordial matter coalesced to form the stars, planetary systems, and galaxies. Why aren’t people similarly skeptical about how the Earth and our Solar system came into being? Some religious fundamentalists, of course, do argue that god created everything and reject pretty much all of science, but I am not talking about them. I am talking about people who have no problem accepting scientific theories of how the entire universe came to be, but yet remain unconvinced that scientific theories can explain how all of life came into being.

There is another possible reason for this focused skepticism against evolution. The Big Bang is a spectacular thing to visualize. There is a magnificence to it that is commensurate with the importance we attach to something that happened at the very beginning of time. But the theory of evolution is the very opposite, saying that life in all its grandeur came about very slowly as a result of a vast number of tiny little plodding steps, each too small to observe. There is no arresting visual image that we can seize upon.

Daniel Dennett’s book Darwin’s Dangerous Idea (1995) says that the basic idea of Darwin’s theory, that everything is a product of an algorithmic process, a simple set of rules mindlessly applied, is what many people find hard to accept.

Among the controversies that swirl around us, most if not all consist of different challenges to Darwin’s claim that he can take us all the way to here (the wonderful world we inhabit) from there (the world of chaos or utter undesignedness) in the time available without invoking anything beyond the mindless mechanism of the algorithmic processes he proposed. (p. 74)

As a result of this skepticism, people have consistently, over time, invoked what Dennett calls skyhooks as explanations. A skyhook is defined as an “imaginary contrivance for attachment to the sky” that can be used for lifting things easily. The skyhook concept is similar to the deus ex machina (“god from a machine”) literary device used by inferior Greek dramatists to suddenly swoop down and lift their characters out of a tight spot. So a skyhook is basically a mysterious and advanced mechanism that can be invoked as an explanation. The existence of skyhooks as explanatory mechanism leads naturally to an acceptance of the existence of a designer, since someone had to have created the skyhook.

The search for skyhooks has historically taken many forms. In the early days, skyhooks were used to explain the appearance of every species. This was the theory of ‘special creation’, popular up to Darwin’s day, where god (the ultimate skyhook) created species to fit into the various ecological niches. As time went by and science explained more and more of what was previously inexplicable, the number of skyhooks needed as explanatory devices has decreased, but never gone away.

The ‘God of the Gaps’ that I have written about earlier is a manifestation of this desire for skyhooks.

The idea of skyhooks is seductive and is what draws many of us in to believing in a creator, especially when we are young. It is a form of magical thinking that all young children find attractive and which is what makes believing in a god easy.

But why do people continue to feel the need for skyhooks as adults when there are other good explanations?

Next: Replacing skyhooks with cranes.

POST SCRIPT: The appeal of skyhooks for children

In this interview with Jonathan Miller, Richard Dawkins says that as a boy he accepted the need for skyhooks for the creation of life, before he discovered that the theory of evolution solved the problem, and the sense of intellectual freedom and liberation that it generated.