River Out of Eden by Richard Dawkins (1995)

Nature is not cruel, only pitilessly indifferent. That is one of the hardest lessons for humans to learn.
(River out of Eden, page 112)

Three things become clear early in this book:

1. Dawkins is very argumentative He can barely state a fact or idea without immediately imagining a scientific illiterate misunderstanding it, or a creationist arguing against it, or the tradition of thinkers who’ve adopted a contrary position, and then – whooosh! – he’s off on one of his long-winded digressions devising metaphors and analogies and thought experiments (‘imagine 20 million typists sitting in a row…’) devoted to demolishing these opponents and their silly beliefs.

The neutral reader sits back, puzzled as to why Dawkins feels such a continual necessity to find enemies and argue against them, constantly and endlessly, instead of just stating the facts about the natural world in a lucid, calm way and letting them speak for themselves.

2. Dawkins is not a mathematician as he points out quite a few times in The Blind Watchmaker. As I read him saying this for the third or fourth time, it dawned on me that this means Dawkins rarely if ever makes his points with numbers – through data or statistics, tables and graphs and diagrams, as a true scientist might. Instead, deprived of numbers (of course he does use numbers, but very sparingly), Dawkins makes his case through persuasion and rhetoric. He is a rhetorician – the dictionary definition being someone who:

exploits figures of speech and other compositional techniques to have a persuasive or impressive effect

Consider the titles of the clutch of mid-career books which I’m rereading: The Blind Watchmaker, River Out of Eden, Climbing Mount Improbable, Unweaving The Rainbow. They are all named for metaphors or analogies for the big Darwinian idea he is so anxious to explicate and defend, and they are themselves made up of chapters which are made up of sections and passages which rely far more on metaphor and analogy and stories and anecdotes than they do on hard data and scientific facts.

3. Dawkins is good at it The four book titles quoted above are all vivid and powerful metaphors for evolution and its implications. The master metaphor which dominates River Out of Eden – that all life on earth amounts to a river of DNA flowing from simple beginnings and then splitting over a billion years or more into thousands and then millions of tributaries, one for each of the species now alive – is a powerful explanatory tool, and leads you on into a series of other analogies and metaphors.

Wrong!

I was amused by the number of times Dawkins mentions or quotes other people – creationists, fellow academics or other biologists – solely to show how their approach or interpretation of Darwinism, biology or anything else is wrong wrong wrong!

He doesn’t hold back. He isn’t subtle or circumspect. He often puts exclamation marks at the end to emphasise just how wrong wrong wrong they are! before proceeding to demolish them one by one! It’s like watching a confident man at a coconut shy throwing the wooden balls and knocking each coconut off, one… by… one. Here’s a selection of his targets:

– Lamarckism or the belief that characteristics organisms acquire during their lives are passed on to their children – ‘Wrong, utterly wrong! (p.3)

– It’s tempting to think of the original branches between what would later turn out to be distinct families or orders of animals as consisting at the time of the first breach ‘mighty Mississippis rivers’ – ‘But this image is deeply wrong‘ (p.10)

– Zoologists are tempted to think of the divide between what later became major groups as a momentous event. But they are ‘misled’ (p.11)

– One zoologist has suggested that the entire process of evolution during the Cambrian period, when so many new species came into existence, must have been a different process from what it is now. ‘The fallacy is glaring!‘ (p.12)

– The digital revolution at the core of the new biology has dealt ‘a killer blow to vitalism, the incorrect belief that living matter is deeply distinct from nonliving material’ (p.20).

– ‘There is a fashionable salon philosophy called cultural relativism which holds… that science has no more claim to truth than tribal myth’. It is, of course, wrong, which he goes on to prove with the fact that tribal myth can’t build the airplanes which fly you to conferences where you can present papers about cultural relativism.

– He once asked a student how far back you’d have to go to find ancestors that Dawkins and the student shared. She replied back to the apes. ‘An excusable intuitive leap, but it is approximately 10,000 percent wrong.’

– Some creationists insist on misinterpreting the scientific concept of Mitochondrial Eve and claim, from the sound of it, that she’s identical with the Biblical Eve! ‘This is a complete misunderstanding.’ (p.62)

And so on…

The trouble with Dawkins’s arguments

There are several practical problems with Dawkins’s relentless argufying.

One is that, because Dawkin is arguing all the time with someone or other, if you put down the book then pick it up later, it’s often difficult to remember the precise Wrong Interpretation of evolution he was in the middle of raging against i.e. to recall the context of whatever scientific information he happens to be presenting.

Making it worse is the way Dawkins often breaks down the argument he’s tackling into sub-arguments, and especially the way he breaks his own counter-arguments down into sub-counter-arguments. And then he’ll say, ‘I’ve just got to explain a few basic concepts…’ or ‘Before I reply to the main thrust of that argument, let me make a small digression…’ leading you steadily away from whatever point you think he was trying to make.

And if the digression takes the form of an analogy, yjrm quite quickly you can be three of four ‘levels’ removed from the initial proposition he’s arguing against. You find yourself needing to follow an analogy he’s using to explain a concept you need to understand in order to grasp the thrust of a part of an argument he’s making against a specific aspect of one particular misinterpretation of evolution.

In other words – it’s easy to get lost.

At several points he asks the reader to be patent, but I wonder how many of his readers really do have the patience to put up with the digressions and analogies.

It’s an oddity of Dawkins’s approach that moments after venting a vivid attack on creationists and Christians for their ignorance, for being ‘wrong, utterly wrong!’ – he will ask them to bear with him, and have a little patience because what follows is only a rough analogy or a hypothetical example or a computer program he’s made up, or some other rather remote and tangential point.

It’s as if someone punched you in the face and then asked you to hold their coat for them. it shows an astonishing naivety and innocence.

And more to the point, the upshot of all these aspects of his approach is that – he never really presents the knock-down, drop-dead, unanswerable counter-arguments against creationist literature which he continually promises.

In fact on several occasions in The Blind Watchmaker he made so many apologies about the absence of current scientific knowledge on a particular point (especially about a) the patchiness of the fossil record and b) the sharply conflicting hypotheses among scientists about how life on earth got started) – or he went on at such length about the arguments and divisions among the scientists themselves – that I emerged with my belief in evolution shaken, not confirmed.

I couldn’t help feeling that, if I was a born-again Christian, a fundamentalist and creationist, Dawkins’s books, with their combination of in-your-face insults with mealy-mouthed, round-the-houses argufying, might well confirm me in my anti-evolutionary beliefs.

The importance of geological time

To summarise Dawkins’s arguments for him, the central foundation of Darwin’s theory of evolution by natural selection is TIME. Lots and lots and lots of time. Geological time. More time than we can possibly imagine. To quote Wikipedia (in order to have the latest, up-to-date info):

The earliest time that life forms first appeared on Earth is at least 3.77 billion years ago, possibly as early as 4.28 billion years, or even 4.5 billion years; not long after the oceans formed 4.41 billion years ago, and after the formation of the Earth 4.54 billion years ago.

Around 4 billion years ago. No human being can understand that length of time.

The next element in Darwin’s theory is the advantage of small changes, minute changes, sometimes molecular changes, in organisms as they reproduce and create new generations. Even minuscule differences, which humans cannot detect, might be the vital determinants in whether an organism just about survives to reproduce, or just fails and is killed or eaten before it reproduces.

Dawkins’s core argument is that, if you set that process in train and let it run for four and a half billion years – then anything can happen, and we have the evidence in the fossil record that it has, that forms of life of surpassing weirdness and sizes and functions have been and gone, and their descendants live on all around us in a marvellous profusion.

It is:

  1. the enormous, impossible-to-conceive length of geological time
  2. and the big difference to its chances of survival which even tiny variants in an organism’s attributes can give it

which anti-evolutionists tend not to have grasped, or understood or have simply rejected. Which drives Dawkins crazy.

The evolution of ‘the eye’

The locus classicus (the classic example) where the two sides clash is THE EYE.

Anti-evolutionary writers of all stripes cite the human eye and assert that it is ridiculously unlikely that The Eye can have just popped into existence in complete perfection, with a fully functioning iris and lens and all the rods and cones which detect light and shade and colour, absurdly unlikely, only a caring Creator God could have made something so wonderful.

AND the related creationist argument, that what possible use would half an eye, or a tenth of an eye or a hundredth of an eye have been to any organism? It must have appeared fully functional or not all.

To which Dawkins and all the evolutionists reply that a) no-one is saying it came into being fully functional and b) you’d be surprised: half an eye is really useful. So is a hundredth of an eye, or a thousandth.

In fact, having a patch of skin which is merely light-sensitive can convey advantage on some organisms. Given enough generations this light-sensitive patch will become a confirmed part of all the members of a particular species, and will tend to form a dip or hollow in the skin to protect itself from damage. If the dip goes deep enough then sooner or later some chance mutation may code for another strand of skin to form across the opening of the dip, with a slight preference given to any variation which creates a membrane which is translucent i.e. lets at least some light through to the light-sensitive skin beneath.

And bingo! The eye!

The killer fact (for me, reading this well-trodden argument for the umpteenth time) is that not only is The Eye not an improbable device for evolution to create in the natural flow of endless variations created in each new generation and likely to be selected because its adds even a smidgeon of survival value to its owners..

But that the formation of The Eye turns out to be a highly probable result of evolution. We know this because we now know that The Eye has evolved at least forty separate times in widely separated orders and families and genera. over the past four and a half billion years. Conclusion:

Never say, and never take seriously anybody who says: ‘I cannot believe that so-and-so could have evolved by natural selection.’ (p.81)

Dawkins dubs this position The Argument from Personal Incredulity, and this discussion of The Eye is one of the few places where Dawkins states an opponent’s argument clearly and then mounts a clearn and convincing counter-argument.

Analogies

Bored with a lot of the these tired old arguments, and of Dawkins’s combative yet strangely naive style, I took to noting the the analogies, reading them as a kind of buried or counter-narrative linking up the boring arguments.

– The river out of Eden is the river of DNA, a river of digital information, which makes up all living things. In fact the river has branched out over the aeons, with countless streams and tributaries running dry but there are, as of now, some thirty million separate rivers of DNA or species.

– Each generation is a sieve or filter: good genes get through, ‘bad’ genes don’t.

– The genetic code is like a dictionary of a language with 64 words.

– the DNA inside each of us is like a family Bible (p.44)

– Insofar as it is digital, the genetic code is like digital phones or computer codes.

– Every cell in your body contains the equivalent of 36 immense data tapes (i.e the chromosomes) (p.21).

– We humans – and all living things – are survival machines designed to propagate the digital database that did the programming.

– The membranes in a living cell are like the glassware in a laboratory.

– An enzyme is like a large machine tool, carefully jigged to turn out a production line of molecules of a particular shape (p.26)

– Cells’ ability to replicate is comparable to the process of ‘bootstrapping’ required in the early days of computing (p.27).

Reading River Out of Eden for the analogies was more fun that trying to follow many of Dawkins’s trains of thought which were often tortuous, long-winded and strangely forgettable.

Credit

River Out of Eden by Richard Dawkins was published by Weidenfeld and Nicholson in 1995. All references are to the 1996 Phoenix paperback edition.


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Seven Clues to the Origin of Life by A.G. Cairns-Smith (1985)

The topic of the origin of life on the Earth is a branch of mineralogy. (p.99)

How did life begin? To be more precise, how did the inorganic chemicals formed in the early years of planet earth, on the molten rocks or in the salty sea or in the methane atmosphere, transform into ‘life’ – complex organisms which extract food from the environment and replicate, and from which all life forms today are ultimately descended? What, when and how was that first momentous step taken?

Thousands of biologists have devoted their careers to trying to answer this question, with the result that there are lots of speculative theories.

Alexander Graham Cairns-Smith (1931-2016) was an organic chemist and molecular biologist at the University of Glasgow, and this 120-page book was his attempt to answer the Big Question.

In a nutshell he suggested that life derived from self-replicating clay crystals. To use Wikipedia’s summary:

Clay minerals form naturally from silicates in solution. Clay crystals, like other crystals, preserve their external formal arrangement as they grow, snap, and grow further.

Clay crystal masses of a particular external form may happen to affect their environment in ways that affect their chances of further replication. For example, a ‘stickier’ clay crystal is more likely to silt up a stream bed, creating an environment conducive to further sedimentation.

It is conceivable that such effects could extend to the creation of flat areas likely to be exposed to air, dry, and turn to wind-borne dust, which could fall randomly in other streams.

Thus – by simple, inorganic, physical processes – a selection environment might exist for the reproduction of clay crystals of the ‘stickier’ shape.

Cairns-Smith’s book is densely argued, each chapter like a lecture or seminar packed with suggestive evidence about what we know about current life forms, a summary of the principles underlying Darwin’s theory of evolution, and about how we can slowly move backwards along the tree of life, speculating about how it developed.

But, as you can see from the summary above, in the end, it is just another educated guess.

Detective story

The blurb on the back and the introduction both claim the book is written in the style of a detective story. Oh no it isn’t. It is written in the style of a biology book – more precisely, a biology book which is looking at the underlying principles of life, the kind of abstract engineering principles underlying life – and all of these take quite some explaining, drawing in examples from molecular biology where required.

Sometimes (as in chapter 4 where he explains in detail how DNA and RNA and amino acids and proteins interact within a living cell) it becomes quite a demanding biology book.

What the author and publisher presumably mean is that, in attempt to sweeten the pill of a whole load of stuff about DNA and ribosomes, Cairns-Smith starts every chapter with a quote from a Sherlock Holmes story and from time to time claims to be pursuing his goal with Holmesian deduction.

You see Holmes, far from going for the easy bits first, would positively seek out those features in a case that were seemingly incomprehensible – ‘singular’ features he would call them… I think that the origin of life is a Holmesian problem. (p.ix)

Towards the very end, he remembers this metaphor and talks about ‘tracking down the suspect’ and ‘making an arrest’ (i.e. of the first gene machine, the origin of life). But this light dusting of Holmesiana doesn’t do much to conceal the sometimes quite demanding science, and the relentlessly pedagogical tone of the book.

Broad outline

1. Panspermia

First off, Cairns-Smith dismisses some of the other theories about the origin of life. He makes short work of the theories of Fred Hoyle and Francis Crick that organic life might have arrived on earth from outer space, carried in dust clouds or on meteors etc (Crick’s version of this was named ‘Panspermia’) . I agree with Cairns-Smith that all variations on this hypothesis just relocate the problem somewhere else, but don’t solve it.

Cairns-Smith states the problem in three really fundamental facts:

  1. There is life on earth
  2. All known living things are at root the same (using the same carbon-based energy-gathering and DAN-replicating biochemistry)
  3. All known living things are very complicated

2. The theory of chemical evolution

In his day (the 1970s and 80s) the theory of ‘chemical evolution’ was widely thought to address the origin of life problem. This stated that lot of the basic amino acids and sugars which we find in organisms are relatively simple and so might well have been created by accident in the great sloshing oceans and lakes of pre-life earth, and that they then – somehow – came together to make more complex molecules which – somehow – learned how to replicate.

But it’s precisely on the vagueness of that ‘somehow’ that Cairns-Smith jumps. The leap from a random soup of semi-amino acids washing round in a lake and the immensely detailed and complex machinery of life demonstrated by even a tiny living organism – he selects the bacterium Escherichia coli – is just too vast a cliff face to have been climbed at random, by accident. It’s like saying if you left a bunch of wires and bits of metal sloshing around in a lake long enough they would eventually make a MacBook Air.

Cairns-Smith zeroes in on four keys aspects of life on earth which help to disprove the ‘chemical evolution’ theory.

  1. Life forms are complex systems. It is the whole machine which makes sense of its components.
  2. The systems are highly interlocked: catalysts are needed to make proteins, but proteins are needed to make catalysts; nucleic acids are needed to make proteins, yet proteins are needed to make nucleic acids;
  3. Life forms are very complex.
  4. The system is governed by rules and conventions: the exact choice of the amino acid alphabet and the set of assignments of amino acid letters to nucleic acid words are examples.

3. The Miller-Urey experiments

Cairns-Smith then critiques the theory derived from the Miller-Urey experiments.

In 1953 a graduate student, Stanley Miller, and his professor, Harold Urey, performed an experiment that demonstrated how organic molecules could have spontaneously formed from inorganic precursors, under conditions like those posited by the Oparin-Haldane Hypothesis. The now-famous ‘Miller–Urey experiment’ used a highly reduced mixture of gases – methane, ammonia and hydrogen – to form basic organic monomers, such as amino acids. (Wikipedia)

Cairns-Smith spends four pages comprehensively demolishing this approach by showing that:

  1. the ultraviolet light its exponents claim could have helped synthesise organic molecules is in fact known to break covalent bonds and so degrade more than construct complex molecules
  2. regardless of light, most organic molecules are in fact very fragile and degrade easily unless kept in optimum conditions (i.e. inside a living cell)
  3. even if some organic molecules were created, organic chemists know only too well that there are hundreds of thousands of ways in which carbon, hydrogen, nitrogen and oxygen can combine, and most of them result in sticky sludges and tars in which nothing could ‘live’

So that:

  1. Only some of the molecules of life can be made this way
  2. Most of the molecules that would be made this way are emphatically not the ‘molecules of life’
  3. The ‘molecules of life’ are usually better made under conditions far most favourable than those obtaining back in the primordial soup era

He then does some back-of-a-matchbox calculations to speculate about how long it would take a random collection of organic molecules to ‘happen’ to all tumble together and create a life form: longer than the life of the universe, is his conclusion. No, this random approach won’t work.

Preliminary principles

Instead, he suggests a couple of principles of his own:

  1. That some and maybe all of the chemicals we now associate with ‘life’ were not present in the first replicating organisms; they came later; their exquisitely delicate interactivity suggests that they are the result not the cause of evolution
  2. Therefore, all lines of investigation which seek to account for the presence of the molecules of life are putting the cart before the horse: it isn’t the molecules which are important – it is the mechanism of replication with errors

Cairns-Smith thinks we should put the molecules of life question completely to one side, and instead seek for entirely inorganic systems which would replicate, with errors, so that the errors would be culled and more efficient ways of replicating tend to thrive on the available source material, beginning to create that dynamism and ‘sense of purpose’ which is one of life’s characteristics.

We keep coming to this idea that at some earlier phase of evolution, before life as we know it, there were other kinds of evolving system, other organisms that, in effect, invented our system. (p.61)

This seems, intuitively, like a more satisfying approach. Random forces will never make a MacBook Air and, as he has shown in chapter 4, even an entity like Escherichia coli is so staggeringly complex and amazingly finely-tuned as to be inconceivable as the product of chance.

Trying to show that complex molecules like ribosomes or RNA or amino acids – which rely on each other to be made and maintained, which cannot exist deprived of the intricately complicated interplay within each living cell – came about by chance is approaching the problem the wrong way. All these complex organic molecules must be the result of evolution. Evolution itself must have started with something much, much simpler – with the ‘invention’ of the basic engine, motor, the fundamental principle – and this is replication with errors. In other words:

Evolution started with ‘low-tech’ organisms that did not have to be, and probably were not made from, ‘the molecules of life’. (p.65)

Crystals

And it is at this point that Cairns-Smith introduces his Big Idea – the central role of clay crystals – in a chapter titled, unsurprisingly, ‘Crystals’ (pp.75-79).

He now explains in some detail the surprisingly complicated and varied world of clay crystals. These naturally form in various solutions and, if splashed up onto surfaces like rocks or stones, crystallise out into lattices, but the crystallisation process also commonly involves errors and mutations.

His description of the different types of crystals and their properties is fascinating – who knew there were so many types, shapes, patterns and processes, starting with an introduction to the processes of saturation and super-saturation. The point is that crystals naturally occur and naturally mutate. He lists the ways they can vary or diverge from their ‘pure’ forms: twinning, stacking errors, cation substitutions, growth in preferred directions, break-up along preferred planes (p.97).

There follows a chapter about the prevalence of crystals in mud and clay and, therefore, their widespread presence in the conditions of the early planet earth.

And then, finally, he explains the big leap whereby replicating crystals may have attracted to themselves other molecules.

There follows a process of natural selection for clay crystals that trap certain forms of molecules to their surfaces that may enhance their replication potential. Complex proto-organic molecules can be catalysed by the surface properties of silicates.

Genetic takeover of the crystals

It is at this point that he introduces the idea of a ‘genetic takeover’.

When complex molecules perform a ‘genetic takeover’ from their clay ‘vehicle’, they become an independent locus of replication – an evolutionary moment that might be understood as the first exaptation.

(Exaptation = ‘the process by which features acquire functions for which they were not originally adapted or selected’)

Cairns-Smith had already described this process – the ‘genetic takeover’ of an initial, non-organic process by more complex, potentially organic molecules – in his earlier, longer and far more technical book, Genetic Takeover: And the Mineral Origins of Life, published in 1982.

This book – the Seven Clues – is a much shorter, non-technical and more accessible popularisation of the earlier tome. Hence the frivolous references to Sherlock Holmes.

Proliferating crystals form the scaffold for molecules which learn to replicate without them

The final chapter explains how these very common and proliferating entities (clay crystals) might have formed into structures and arrangements which attracted – for purely chemical reasons – various elementary organic molecules to themselves.

Certain repeating structures might attract molecules which then build up into more complex molecules, into molecules which are more efficient at converting the energy of the sun into further molecular combinations. And thus the principle of replication with variation, and competition for resources among the various types of replicating molecule, would have been established.

Thoughts

At this point the book ends, his case presented. It has been a fascinating journey because a) it is interesting to learn about all the different shapes and types of clay crystal b) he forces the reader to think about the fundamental engineering and logistical aspects of life forms, to consider the underlying principles which must inform all life forms, which is challenging and rewarding.

But, even in his own terms, Cairns-Smith’s notion of more and more complex potentially organic molecules being haphazardly replicated on a framework of proliferating clay crystals is still a long, long, long way from even the most primitive life forms known to us, with their vastly complex structure of cell membrane, nucleus and internal sea awash with DNA-controlled biochemical processes.


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