The key steps in adopting evolution

(My latest book God vs. Darwin: The War Between Evolution and Creationism in the Classroom has just been released and is now available through the usual outlets. You can order it from Amazon, Barnes and Noble, the publishers Rowman & Littlefield, and also through your local bookstores. For more on the book, see here. You can also listen to the podcast of the interview on WCPN 90.3 about the book.)

Making a Gestalt-type switch is often aided by nudges from outside sources, and in the case of evolution, two such factors came into play: the age of the Earth and concerns about the effects of human population growth.

Darwin was fortunate that he lived in a time when advances in knowledge in other areas, such as the idea of uniformitarianism in geology, were coming along at the same time that he was pondering all the things he was observing on his voyage on the Beagle. The first edition of the first volume of Charles Lyell’s highly influential book The Principles of Geology was published in 1830 and was given to Darwin to read on his voyage on the Beagle that began in 1831. Its argument that small changes (such as erosion) can accumulate over long periods of time to produce major geological features such as mountains and gorges had an impact on him.

By measuring the rates of erosion and sedimentation that were occurring in his own time and calculating how long it would take at that rate to produce the existing rivers and canyons, Lyell concluded that the Earth must be hundreds of millions of years old. Furthermore, Lyell’s books discussed some of the fossil evidence that existed at that time because he used them as aids in arriving at the ages of rocks, although Lyell himself believed in special creation.

The fact that the Earth was now possibly hundreds of millions of years old, rather than merely thousands, created an intellectual environment that was more open to acceptance of the idea that new species can gradually evolve from old ones, because that needed long time spans too.

Darwin (and also Wallace) had a Gestalt-type switch when he was struggling to find the mechanism that causes species to evolve in a way that seemed to indicate directionality. The trigger was Thomas Malthus’s Essay on the Principle of Population (1798) that argued that populations would grow exponentially, except for the fact that they encounter limited resources that restricts growth because of starvation and premature death. This gave Darwin the idea that natural selection could serve as the mechanism he was looking for. In The autobiography of Charles Darwin 1809-1882 (Nora Barlow (ed), 1958, page 120), he describes his epiphany in ways that suggest a Gestalt-type switch:

In October 1838, that is, fifteen months after I had begun my systematic enquiry, I happened to read for amusement Malthus on Population, and being well prepared to appreciate the struggle for existence which everywhere goes on from long-continued observation of the habits of animals and plants, it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The result of this would be the formation of new species. Here, then, I had at last got a theory by which to work. (my italics)

Darwin and Wallace saw that if there are variations, then it makes sense that some variations are more likely to survive to adulthood and produce more offspring than others. If this advantageous property is heritable and passed on to its offspring then, over time, that particular variation will dominate the population. And by a very long series of such small changes, new species would emerge.

Once Darwin saw the world in this new way, there was no going back. And the rest, as they say, is history.

I have argued that the kinds of switches in viewing the world that Darwin and Wallace experienced are like Gestalt switches in perception. When one changes one’s perspective, suddenly things fall into place and new patterns emerge. What seemed inexplicable, mysterious, and even impossible before suddenly seems clear and even obvious. And once the new way of seeing things is pointed out to others, they immediately see it as obvious too. As Thomas Huxley said after learning how the theory of evolution worked, “How extremely stupid not to have thought of that!” As a result, the new view spreads like wildfire.

But even when told what to look for, not everyone makes the switch. There are some people who never see the new pattern, either because of a rigidity of attitude or, as we will see in the next posting in the case of evolution, because they do not want to see the new pattern because they cannot bear to give up the old one. For them the duck remains a duck and they never see a rabbit.

Next: The mental block of creationists

POST SCRIPT: Well, that didn’t take long!

On Tuesday, I wrote about the atheist billboard campaign in Ohio, putting up three billboards near Cleveland, Columbus, and Cincinnati. Some godly people in the Cincinnati area have already taken offense and threatened violence, requiring the billboard to be moved to another location.

See here for more details.


  1. says

    Really enjoying this sequence of articles, Mano. I’m left with little comment, except thinking to myself, “Yeah, that’s right!” But I feel bad for not giving you the feedback you deserve, so I thought I should actually make a comment. So, here ya go!

    You have a gift for putting things into simple, intuitive explanations. I’m buzzing with anticipation to see what you have to say about the mental blocks of creationists and how it relates to gestalt switching. It’s fascinating to me, the whole topic.

    For me the gestalt-switch is highly interconnected with the ideas of intuition and Eureka! or “Ah ha!” moments. You need to build up an adequate vocabulary of intuitive concepts. Then, once you have a sufficient supply of these concepts available to you, you can then simply connect a couple of them together, and things start to make a new kind of sense all of a sudden (a gestalt switch). Along with this connection, comes a certain feeling, the ‘Ah ha!’ feeling, which I associate with the natural feeling of ‘wonder’ (hence my nickname).

    I have an idea, as yet unsubstantiated, that this ‘Ah ha!’ moment corresponds exactly with an actual brain event, the formation of a new synapse between neurons (or the sudden strengthening of a previously weak synapse), followed by a cascade of new neuronal connections being made as the significance of the first new connection seeks a ‘lower energy state’ (which is merely an analogy to chemical reactions which must pass an activation barrier, but which then release energy to fuel even more molecules to get over the barrier, which release more energy, etc.), and each new connection triggers a small amount of ‘wonder’.

    The bigger the gestalt switch, the more new connections are formed, and the greater the sense of wonder.

    But without all those preceding intuitional concepts forming a basis of vocabulary to think about the issue, the crucial connection cannot be made, or does not stick if made prematurely.

    Imagine a pile of mechanical parts. Workers proceed to take various parts and connect them. Still, it appears a pile of junk. Eventually, some of the parts are joined into larger assemblies, and you can get the sense that there are distinct components being built. But still, it’s just a pile of disjoint components. Eventually, a framework is laid down, and a few of the most basal components are connected together in a shape that seems to make a bit of vague, intuitive sense. Then, more components are cumulatively connected to this framework, and it begins to appear that there’s some logic to this mess. Soon, a clear boundary is formed around the framework and its components, and there’s a clear sense that the whole thing makes some sort of sense. But there are still a few disconnected components, and that makes the whole not-quite-yet-functional. Finally, the last component is dropped in place.

    What was initially a pile of parts is not a functional automobile (for example). Now all it takes is for you to turn the key, and VROOM! the things jumps to life.

    Before all that heavy work, the key could not do anything. But after all the concepts are in place, the key gives an exciting result.

    That’s how I think gestalt-switches work. Some cars are more complex, and therefore need more up-front work, than others, but the process is the same.

    Now, it is difficult to see the car as ‘just a bunch of parts’. It seems to be a whole unitary thing of its own.

    Some gestalts allow you to switch from one perspective to the other, but I think the more complex ones tend to be one-way, just as some chemical processes are easily reversible, while others tend to go in one direction and stay there.

    Lots more ideas on this, but I think that’s enough for now.

  2. says


    While I would like to think that when we learn something new it creates new synapses, the speed of new synapse formation seems to be much slower than the suddenness of learning something new or making a Gestalt switch. There has to be a deep underlying connection somewhere but I am still trying to figure it out.

  3. says

    Well, then perhaps it’s more of a strengthening or synchronization. Two neurons that once were working at odds are now working together. Information flow has found a new pathway that was blocked before. That sort of thing.

  4. says

    The unblocking of an old pathway would explain the suddenness feature. But wouldn’t it also mean that we already had that knowledge before it got blocked? So we did not learn anything new, we just relearned something old?

  5. says

    “But wouldn’t it also mean that we already had that knowledge before it got blocked?”

    No. This is why I tried to emphasize the prior learning of foundational, intuitional concepts.

    The key is the making of a new connection between existing concepts.

    But once that connection is made, a whole cascade of other changes, other connections, are made in rapid succession.

    The initial change is small, but the subsequent changes — though each also small on its own — add up to a much bigger overall change.

    Imagine a river flowing for thousands of years. One of its banks has been slowly eroding over this time. Suddenly, one day, a little rock is swept away by the current, and a trickle of water flows over this bank.

    Now, it depends on what’s the terrain on the other side of the bank (prior concepts). If the terrain is just more dirt, then nothing really happens.

    But if the terrain has been cleared away by other processes (prior learning of concepts), then the trickle can flow down into a lower terrain. The trickle continues to erode the bank, and eventually cuts right through it, and the river changes course.

  6. says

    I’ll try to give a concrete example. Okay, I use this example a lot:

    When I was around 12, I had seen the word ‘enzyme’ used in many different places, but I couldn’t figure out from the context what it meant. The ‘enzyme’ concept in my brain was simple and undifferentiated, almost meaningless. It had no connections with other concepts.

    So, one day I was bored in the library, and I decided to flip through an encyclopedia. I thought, “Why not? I’ll look up ‘enzyme’.” So I did. And I started reading about how enzymes are proteins (*connect* to ‘protein’, which also was a fairly undifferentiated concept, but at least it was connected to things like ‘muscle’), and they are also catalysts (*connect* to ‘catalyst’, which I also knew vaguely about). I also learned that the stomach contains enzymes, such as pepsin (*connect* to ‘stomach’. *new* concept ‘pepsin’). I looked up ‘pepsin’, and discovered that its function is to break down proteins (*connect* to ‘break down’, *connect* to ‘protein’).

    This puzzled me, because pepsin is an enzyme, which is a protein, which breaks down proteins. Wouldn’t pepsin break itself down? I continued on.

    I learned that proteins are made of amino acids (*connect*) and that the sequence (*connect*) of amino acids determines the folding (*connect*) and thus the function (*connect*) of the protein. Those proteins whose function is catalysis are called enzymes (*connect, connect, connect* mini “Ah ha!” moment).

    Then I learned that the sequence of the amino acids is determined during protein synthesis by the original sequence in DNA (*connect*), and that a gene (*connect*) is a sequence of DNA that encodes a protein.

    Finally, I learned that the DNA sequence is determined by evolution (*connect*) by natural selection (*connect*).

    BAM! All of a sudden, that last connect put me over a threshold. I could now see the connection from DNA, to synthesis, to amino acid, to protein, to folding, to function, to catalysis, to enzyme, to pepsin, to digestion, to food, to survival, to natural selection, to evolution, and back to DNA.

    There were *connects* and *new* concepts galore. It was a huge “Ah ha!” experience. So many previously separate ideas began to fit together into a cohesive whole, like the newly assembled car getting its ignition turned on, and the power going to the spark plugs, to the gas, to the piston, to the engine, to the VROOM.

    If I had stopped reading at the part about protein synthesis, I would have learned some new concepts, and would have had plenty to ponder over for weeks and months.

    But just reading those last few concepts, especially the connect to evolution, was enough to open up a whole new way of thinking, a whole new course for my conceptual river to follow.

    If I had stopped, I would have eventually learned about evolution years later, probably when I was 17 or 18. But by just making that one small connection, the *prior concepts* were all joined together into a whole.

    Without the prior concepts, the words ‘evolution’ and ‘natural selection’ had a kind of vague sense to them as well. It *required* having the prior concepts in place, but that alone wasn’t enough. There needed to be that final connection which set off that whole cascade of new connections (and resulting understanding).

    So, that’s how I think of gestalt switches. If you don’t have the background knowledge, they won’t work. If you’ve never seen a Dalmatian before, or have insufficient experience with dog anatomy and behaviour (e.g. sniffing the ground), then you’re never going to see the Dalmatian.

    But even with vast experience with Dalmatians, you probably aren’t going to see the Dalmatian right away either. It requires that final connection, such as, perhaps, “Hmm, there’s a bunch of spots all jumbled together. What else has a bunch of spots? Maybe a cheetah? Maybe a dog? *connect* Ah ha! *connect connect connect* There it is! That’s amazing.”

    So, no, it’s not the ‘unblocking of an old pathway’, it truly is the creation of a brand new pathway. But it *does* require the necessary terrain, the prior concepts, for the gestalt switch to work.

    With those prior concepts in place, a tiny connection can trigger a cascade of many other connections, which opens up a relatively large flood of understanding.

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