Kenny on Noble

Anthony Kenny on Denis Noble:

When I was a bachelor don at Balliol I shared a staircase with Denis Noble, who was a physiology tutor: my rooms were on one side of the staircase and his on the other. We were both courting at the time, and so would also meet each other's fiancées on the stairs. We shared students as well as premises. There was an honour school called PPP: Psychology, Philosophy and Physiology. Denis taught the students physiology and I taught them philosophy. At meals in college we often discussed topics of common interest: Denis was not only a physiologist but as competent a philosopher as any of my colleagues.

In those days, there was a broad consensus that the sciences formed a hierarchy in which each level was to be explained in terms of the one below it: psychology was to be explained by physiology, physiology by chemistry, and chemistry by physics. This scientific strategy was called 'reductionism', since all sciences were ultimately to be reduced to physics. The idea was pithily expressed by Jim Watson, one of the discoverers of DNA: 'There are only molecules – everything else is sociology.'

Reductionist science chalked up victory after victory, as more and more lower-level mechanisms were discovered to explain higher-level processes. One such discovery was made in 1984 by the young Denis. He explained the pacemaker rhythm of the heart in terms of the flow of ions of potassium and calcium through protein channels. This achievement established his credentials as a reductionist biologist. However, he did not long continue to be a card-carrying member of the fraternity. He soon realized that in the heartbeat there was not only upward causation from the molecular level to the cellular level, but also downward causation from the cell influencing the molecules. Denis chaired the meeting at which I challenged Dawkins on the explanatory power of genes, and he took my side in the argument.

After I became Master of the college I ceased to share students with Denis, and so we had less opportunity for scientific discussion. However, our paths remained entwined at an administrative level. For two years, Denis served as my vice Master. This period included the year in which Mrs Thatcher was proposed, and then rejected, for an honorary Oxford degree. Denis was a founder of the Save British Science campaign which protested against the Thatcher government's cuts to the science budget, and he took a leading part in the campaign against the proposal. After the proposal was rejected, 200 alumni wrote separate letters to Balliol, either to applaud or to condemn the decision of Congregation. Denis and I divided between us the burden of replying. I, who had voted in Council in favour of the degree, wrote to the pro-Thatcher correspondents, while Denis wrote to the rest.

In retirement, I have been delighted to resume philosophical and scientific discussions with Denis. He has now come a long way from his reductionist beginnings. In his latest book, Dance to the Tune of Life, he enunciates a principle that he calls 'biological relativity'. This states that in biology there is no privileged level of causation: living organisms are multilevel open systems in which the behaviour at any level depends on higher and lower levels, and cannot be fully understood in isolation. Levels are distinguished from each other by their degree of complexity. If we start with atoms, we move upward through the levels of molecules, networks, organelles, cells, tissues, organs, whole-body systems and whole organisms.

One of the goals of reductionism was to eliminate from science all teleology or goal-directedness. In fact, Noble argues, teleology is ubiquitous in nature. However, it operates in different ways at different levels. At the purely molecular level, the protein-membrane network that sustains cardiac rhythm has no goal: its function only becomes clear at the level of cells. In its turn, the cellular activity serves a purpose that only emerges at the still higher level of the cardiovascular system.

While he remains a thoroughgoing Darwinist, Denis challenges the neo-Darwinism of Dawkins. He rejects the assumption that natural selection working on chance variations in genetic material is entirely sufficient to explain all evolutionary change, and has followed up the critique of The Selfish Gene that we began in his Holywell Manor drawing room years ago. In Dance to the Tune of Life, he argues that genes are not agents – selfish or unselfish: they are only templates – mere organs of the living cell:

There is nothing alive in the DNA molecule alone. If I could completely isolate a whole genome, put it in a Petri dish with as many nutrients as we may wish, I could keep it for 10,000 years and it would do absolutely nothing other than to slowly degrade.

Moreover, DNA is not sealed off from the outside world: it is subject to modification from within the organism and from the environment. Human beings and other animals are not lumbering robots but autonomous agents who can affect not only their environment but also the make-up of their own genome.

In 2017, Denis organized a joint conference between the Royal Society and the British Academy on the new trends in evolutionary biology. Despite attempts made to block it by outraged neo-Darwinists, the conference was well attended and excited all the participants. I am proud to have had a hand in the early stages of its organization. Its proceedings have recently been published by the Royal Society in its journal Interface Focus.

To this day, Denis and I continue our discussions on the relationship between philosophy and science. We both agree that the notion that science is necessarily and uniquely reductionist is not an empirical discovery, but a philosophical postulate. We both agree that teleology is undeniable and ubiquitous, but that we do not know, and perhaps cannot know, whether this is simply a fundamental feature of nature, or whether there is some supreme level at which it has an explanation. Certainly science cannot tell us whence the universe originated, and whether it has an ultimate goal. In his latest book, Denis suggests that even in asking these questions we have reached a boundary across which we cannot go.

(Brief Encounters: Notes from a Philosopher's Diary, pp 185-188.)