thinking makes it so

There is grandeur in this view of life…

Masters of war

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Why should evolution be at all relevant to ethics? Well, because (1) the kind of ethics we humans are primarily interested in is the ethics of how we humans interact with each other; and (2) we humans, with all our physical, behavioural and cognitive features, are products of evolution.

Perhaps not everyone would agree with both these statements – particularly the second – but for now I am taking them as sound assumptions. If that means I am primarily addressing an audience which shares these assumptions, so be it.

This article follows Great god progress in a discussion on The ethics of belief.

I was originally intending to review the thinking of other and later contributors to evolutionary theory (eg TH Huxley’s grandson Julian Huxley) but I think that would be too much of a tangent. The material is available elsewhere, generated by far greater experts than I. I don’t want to risk confusing my main argument with too much background and preamble.

So I shall try to make my point as clearly as possible, and only then consider what else I might need to add to make it more convincing. But as I’ve said before, I only need to make its feasibility convincing, not necessarily demonstrate its truth.

The starting point is my understanding of contemporary evolutionary thinking. But because I want to develop an argument involving ethical concepts I want to make it very clear that I am not trying to derive ethical values – either positive or negative – from any direction suggested by evolution. In that sense I want to keep firmly within the ‘Evolution is neutral’ position summarised in Darwin’s bulldog.

Replication of replication

At risk of understatement, I am struck by the profound simplicity and explanatory power of the contemporary synthesis of evolutionary thinking. If I understand it correctly, the idea is that, however sustainable physical replication first emerged, once it did emerge, it provided the engine not only for life itself but for the diversity found among living things.

The primary replication is of course that of genetic material (which for most contemporary forms of life means chromosomes made up of sequences of genes), rather than the secondary replication of somatic structures like leaves and legs, which happens as a result of genetic replication.

But the theory is not just about replication. A few other factors must be added to the mix. One, even simpler than replication, is high numbers. The period of time which has elapsed since the conditions were right for life on our planet is so immense we sometimes struggle to grasp its implications.

Then another battery of high numbers in generated by replication itself. This is particularly significant considering how much evolution of inheritable patterns and structures (multicellularity, sexual reproduction, aerobic respiration, the digestive system etc etc) took place within ancestors which enjoyed far higher reproductive capacity and far lower reproductive cycle times than occur in mammals, let alone humans. A single individual producing 10 offspring per cycle will generate 26 billion individuals after 10 cycles – assuming they all survive of course.

Another factor, grounded in the physical mechanism of replication, is variation resulting from intermittent errors in the replication process. Not all of that theoretical 26 billion will be exact copies. Some will include mutations. The majority of mutants may well be defective, perhaps not even viable. So after 10 cycles the actual total may be a lot less than 26 billion. But a proportion of mutations will be viable and inheritable; and in the context of competition (which is the last of our key evolutionary factors) some will be advantageous.

Replication is a physical process requiring energy and building materials. Accessible resources of the right kinds of these will be finite. So replicating entities which, by undergoing viable and inheritable variation, evolve features which improve their access to and/or exploitation of appropriate resources will enjoy advantages relative to their competition, and therefore survive at the expense of their competition.

Advantageous variations could be things like absorbing solutes at higher or lower concentrations or accessing energy at higher or lower intensities or in different forms. Or they could lead to exploiting secondary sources – like other replicating entities themselves, either ‘dead’ or ‘alive’ – and so not having to rely on primary sources like sunlight, water and atmospheric gases. Once this happens, any replicator which is a potential nutrition source for other replicators is competing not just for resources but for survival itself.

So driven purely by potentially infinite (but not infinitely perfect) replication within a finite resource pool, our community of replicators will inevitably descend into a something like the ‘war of all against all’ (bellum omnium contra omnes) which Hobbes1 saw as the state of nature for mankind.

In all wars there is an arms race. But this ‘evolutionary arms race’2 has no conscious deliberation behind it. Nothing is thinking ‘I must do x to survive’, then does x, and so survives. It is the replicator which randomly mutates so as to do x – or something equivalent – which survives to replicate. That is all the ‘survival of the fittest’ means. Fitness is purely in terms of survival so as to have maximum numbers of viable replicating progeny. ‘Survival of the survivors’ would be more precise but it doesn’t quite roll off the tongue.

As mentioned in Great god progress, it is primarily the arms race which generates complexity, sophistication and design – if this is what survival demands. ‘Arms race’ should be broadly construed, to cover eg the offensive ‘tooth and claw’ weaponry of carnivores; the escape velocity of antelopes; camouflage of both hunter and hunted; plant poisons to deter herbivores; protective mimicry among moth caterpillars; and countless more, stretching blind ingenuity to its limits.

The reason for saying the arms race is the primary generator of diversity is purely to acknowledge that the analogy almost fits but not exactly. Inherited variation which improves an organism’s exploitation of primary resources (inorganic energy sources, water, atmosphere, minerals), or which increases its longevity or reproductive capacity, cannot strictly speaking be classified as offensive or defensive weaponry, as there is no ‘enemy’ or ‘rival’.

The point though is that advantageous variation within a replicator’s competitors is continually (in the context of an evolutionary timeframe) intensifying the struggle for survival. The domain of primary resources may go through periodic change (volcanic activity polluting the atmosphere and reducing sunlight; encroaching and receding ice ages; …) but there is no equivalent ‘competition’ in design complexity from that quarter. The bottom line is that the ‘arms race’ is not the only driver of evolutionary change, but its contribution to change – and in particular its contribution to diversity – is overwhelming.

Kith and kin

The diversity is not just physical. As animal nervous systems evolved, sentience and behaviour diversified. And just as it is rare in human history for warfare to be literally all against all, so elsewhere in nature competitive behaviour has diversified to accommodate symbiotic and commensal relationships between individuals of different species, and social structures and alliances between those of the same species.

A replicator which mutated so as to recognise its own offspring and devour them would not leave many offspring behind. This would be an evolutionary cul-de-sac to end all culs-de-sac. By contrast a replicator which mutated so as to recognise its own offspring and help them to survive would, other things being equal or almost equal, leave more offspring than one without the mutation. This, simplified almost to absurdity, is the logic behind kin selection. At the level of the individual gene, kin selection goes beyond direct offspring to other family members (eg siblings and cousins) which have a mathematically calculable probability of possessing a copy of the same gene.

But cooperative behaviour among at least some animals – including humans – goes beyond kin and extends also to unrelated neighbours (‘kith’).

For a long time biologists were stumped as to how social cooperation had evolved, assuming natural selection operated at the level of the individual organism. Cooperation – for example that of wolves hunting in packs – makes obvious sense in the long run. But it was unclear how that long run was ever reached. Consider a mutation in an individual proto-wolf which led it to forego the chance to kill and eat a rabbit and instead help another bring down an antelope. How could a mutation like that survive natural selection? Surely purely selfish or kin-directed strategies (like sticking to rabbits and hiding the kill from all but family; or pretending to cooperate in an antelope kill but then whisking the best bits away before your allies had a chance to get their teeth into it) would always be selected for over more generous tendencies?

Then in the early 1970s Robert Trivers used mathematical models to establish how reciprocal altruism could have evolved. Subsequent research has extended and deepened the explanatory theory. Computerised simulations have been particularly important, showing how different inherited behavioural strategies might fare after multiple generations.

The theory is well documented and available from many sources (eg Nowak, 20063; Trivers, 19714; Dawkins, 19905; Hauser, 20086), so does not need repeating here.

What we do need to look at though is the relationship between the Golden Rule, Kant‘s categorical imperative, and reciprocal altruism as an evolved behavioural strategy. This will be the subject of the next article in this series.

References

1 Thomas Hobbes, De Cive, 1642.

2 Richard Dawkins, The selfish gene, second edition, 1990.

3 Martin Nowak, Five rules for the evolution of cooperation, in: Science 314, 2006.

4 RL Trivers, The evolution of reciprocal altruism, in: Quarterly Review of Biology, 46, 1971.

5 Richard Dawkins, op.cit.

6 Marc D Hauser, Moral Minds, Abacus, 2008.

© Chris Lawrence 2009.

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