Paul Nurse: "What is Life?"

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“Creation myths exist in most cultures” says Paul Nurse. But, he claims, the creation myth of his own community, professional scientists, is an exception. The creation myth of that community, natural selection, he presents to us as science.

Why is it so important to Nurse and many of his fellow geneticists that natural selection be accepted as science? “I should say, right at the start, that we biologists often shy away from talking about great ideas and grand theories.” Fine. But then, “important overarching ideas of this kind do exist in biology, and they help us make sense of life in all its complexity.” So, better a myth than no explanation at all?

Nurse begins by accounting for life in the familiar terms of cell, genes and biochemistry. His overall theme here is, life is extremely complicated. He documents this with reference quite dutifully to his own work and the discoveries of eminent scientists such as Lavoisier, Pasteur and Berthelot.

The other two of his five big ideas are information and natural selection. Here by contrast he provides very little backup. Instead what he offers us reads to me like ideological doctrine. First, he says, to probe its complexity we should study life as information—"Information is at the centre of the butterfly’s existence and indeed at the centre of all life.” Really? And for this study our main organizing principle should be natural selection, natural selection being what drives life’s tendency to complexity, defines the lines it runs on. Oh, yes! He offers no proof for any of this, as if expecting us to accept it as self-evident, already established.

As the book progresses natural selection is hailed as the solution to all life’s mysteries:

As we have seen, life’s innovations arise as a consequence of random genetic mutations and variations. These are then sifted by natural selection, with those that work well being assimilated into the surviving, more successful, living organisms.

The ruthless winnowing process of natural selection has created many unexpected things. One of the most extraordinary of these is the human brain… All of this has happened through the blind and unguided, but highly creative, process of evolution by natural selection…. Evolution by natural selection describes how different life forms can come about and attain purpose… It is driven by chance and steered by the necessity of generating increasingly effective life forms…

Somehow, somewhere, a very long time ago inanimate and disordered chemicals arranged themselves into more ordered forms that could perpetuate themselves, copy themselves and eventually gain the all-important ability to evolve by natural selection.

Once we allow natural selection to do its work, he insists, there is nothing left over to account for:

We now know that complex life forms endowed with a sense of purpose can be generated without a designer of any kind, and that is due to natural selection… Evolution by natural selection can bring about great complexity and the apparent purposefulness of living things. It does this without any controlling intellect, defined end goal, or ultimate driving force… Natural selection is the intensely creative process that has produced us…

For professional scientists such as Nurse, calling natural selection “science” spreads support for their belief in physical determinism, a belief to which Nurse freely testifies:

Ultimately, life emerges from the relatively simple and well-understood rules of chemical attraction and repulsion, and the making and breaking of molecular bonds … The notion that cells, and therefore living organisms, are astoundingly complicated, but ultimately comprehensible, chemical and physical machines is now the accepted way to think about life.

What about mind, consciousness, free will?

Our self-conscious minds must have evolved, at least in part, to give us more leeway to adjust our behaviour when our worlds change. Unlike butterflies, and perhaps all other known organisms, we can deliberately choose and reflect upon the purposes that motivate us. The brain is based on the same chemistry and physics as all other living systems. Yet somehow, from the same relatively simple molecules and well-understood forces, spring our abilities to think, to debate, to imagine, to create and to suffer.

He appears to welcome contributions from people more vested in what scientists like to mock as “folk psychology”—belief in free will and an autonomous consciousness:

We have barely scratched the surface of understanding how the interactions between billions of individual neurons can combine to generate abstract thought, self-consciousness, and our apparent free will… Finding satisfactory answers to these questions will probably occupy the twenty-first century and likely beyond. And I do not think we can rely only on the tools of the traditional natural sciences to get there. We will have to additionally embrace insights from psychology, philosophy and the humanities more generally… It will take all our imagination and creativity to understand how imagination and creativity can come about.

Here, a novelist, a poet or an artist can help, by contributing to the basis of creative thoughts, by more clearly describing emotional states, or by interrogating what it really means to be. If we have more of a common language, or at least greater intellectual connection, between the humanities and the sciences to discuss these phenomena, we may be better placed to understand how and why evolution has allowed us to develop as chemical and informational systems that have somehow become aware of their own existence. 

“But if we ever do,” he concludes, “I am confident they, like us, will be self-sustaining chemical and physical machines, built around information-encoding polymers that have been produced through evolution by natural selection.” Any alternatives that depart from his community’s belief in physical determinism he is likely to reject.

Are there sufficient grounds for challenging these ideas of Nurse’s? I think so. As is testified to by equally-eminent evolutionists at thethirdwayofevolution.com, modern genomics in fact casts doubt on the efficacy of natural selection. It can select only for characteristics making for fitness in the phenotype but such characteristics seldom correspond one to one with particular genes. Nurse admits this: “Most common diseases and disorders, including heart disease, cancer and Alzheimer’s disease… are caused by the combined influences of many individual genes which operate and interact with each other.” Natural selection’s ability to select for individual characteristics is irrelevant to evolution in terms of gene frequencies, which is how we assess evolution today. That requires some other mechanism.

I’ll qualify that: natural selection can act as the mechanism for what is called “microevolution.” Darwin, after titling his book “On the Origin of Species by Means of Natural Selection” thought better of that and added the more appropriate subtitle, “The Preservation of Favoured Races in the Struggle for Life.” Just races, just selection of alternate existing alleles. But not species, involving the creation of new genes, that may involve collaboration among as many as a thousand individual nucleotides. For them to be selected by natural selection they’d first have to be selected for one by one, each for its own individual increment of fitness, prior to the quite different fitness each must contribute later to the completed functional gene.

Nurse tilts discourse about evolution further towards physical determinism by making information theory essential to the study of life. But information thinking has already been applied to life, and usually falls short. Population statistics, for example; can natural selection protect all essential genes from loss through disuse, as well as any beneficial mutations? I don't think so. Here's another problematic use of information thinking: Ronald Fisher, in totting up the effects of mutations over time included only those due to beneficial mutations, ignoring those due to mutations that were harmful--he was gratified when his results defied thermodynamics! Uh-oh! Similar thinking led to absurdities in kin selection--why will mothers sacrifice themselves to save their first-born, when the mother retains more chances of passing on her genes, as eagerly as to save her last born? The track record of information thinking's effect on the understanding of life has not been promising. 

I can testify to how, once you doubt natural selection, it unravels quickly into nonsense. According to Nurse, susceptibility to natural selection is itself under natural selection’s control. Now compare two populations, one that suffers no damage to its genes, and another in which random damage to its genes is given free reign. Which is more likely to survive? One in which harmful mutations ("the great majority" acknowledged Julian Huxley in "The Modern Synthesis") accumulate generation by generation, only a little offset by occasional genes conferring benefit? Obviously not. To eliminate all harmful damage and save only beneficial genes natural selection would have to be 100% efficient, which no one believes.

What can account for Nurse’s passionate advocacy of unfounded ideas? “… natural selection… is a mechanism—in fact, the only mechanism we know of—that can generate diverse, organized, purposeful living entities without invoking a supernatural Creator.” In other words, Nurse’s primary standard for the validity of a theory of evolution is that it contradicts religious accounts of creation. To him it doesn’t matter that his theory also denies the possibility of conscious expression of a free will, to some extent at least free of determinism by today’s laws of physics, because by being non-physical it also must be "supernatural." Presumably he is content that his book may contribute to the denial of that possibility in the school science classroom.

I’ve included my review of Nurse’s book among my category of “Classic” texts both because his eminence and reputation as a scientist are likely to make his book the standard popular guide to evolution, and because I want to draw attention to it as representative of the greatest scandal of modern science, that natural selection should still be talked about as the primary mechanism of evolution when it better deserves to be recognized as capable of no more than selection among existing gene variants. For an alternative see my "New Philosophy of Evolution" article and "Are You Wonderful?".

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