Rupert's Reply for the Reality Club - 2005
WHAT I BELIEVE IS TRUE EVEN THOUGH I CANNOT PROVE IT
There is no need to suppose that all the laws of nature sprang into being fully formed at the moment of the Big Bang, like a kind of cosmic Napoleonic code, or that they exist in a metaphysical realm beyond time and space.
Before the general acceptance of the Big Bang theory in the 1960s, eternal laws seemed to make sense. The universe itself was thought to be eternal and evolution was confined to the biological realm. But we now live in a radically evolutionary universe.
If we want to stick to the idea of natural laws, we could say that as nature itself evolves, the laws of nature also evolve, just as human laws evolve over time. But then how would natural laws be remembered or enforced? The law metaphor is embarrassingly anthropomorphic. Habits are less human-centred. Many kinds of organisms have habits, but only humans have laws.
Habits are subject to natural selection; and the more often they are repeated, the more probable they become, other things being equal. Animals inherit the successful habits of their species as instincts. We inherit bodily, emotional, mental and cultural habits, including the habits of our languages.
The habits of nature depend on non-local similarity reinforcement. Through a kind of resonance, the patterns of activity in self-organizing systems are influenced by similar patterns in the past, giving each species and each kind of self-organizing system a collective memory.
Is this just a vague philosophical idea? I believe it can be formulated as a testable scientific hypothesis.
My interest in evolutionary habits arose when I was engaged in research in developmental biology, and was reinforced by reading Charles Darwin, for whom the habits of organisms were of central importance. As Francis Huxley has pointed out, Darwin's most famous book could more appropriately have been entitled The Origin of Habits.
Over the course of fifteen years of research on plant development, I came to the conclusion that for understanding the development of plants, their morphogenesis, genes and gene products are not enough. Morphogenesis also depends on organizing fields. The same arguments apply to the development of animals. Since the 1920s many developmental biologists have proposed that biological organization depends on fields, variously called biological fields, or developmental fields, or positional fields, or morphogenetic fields.
All cells come from other cells, and all cells inherit fields of organization. Genes are part of this organization. They play an essential role. But they do not explain the organization itself. Why not?
Thanks to molecular biology, we know what genes do. They enable organisms to make particular proteins. Other genes are involved in the control of protein synthesis. Identifiable genes are switched on and particular proteins made at the beginning of new developmental processes. Some of these developmental switch genes, like the Hox genes in fruit flies, worms, fish and mammals, are very similar. In evolutionary terms, they are highly conserved. But switching on genes such as these cannot in itself determine form, otherwise fruit flies would not look different from us.
Many organisms live as free cells, including many yeasts, bacteria and amoebas. Some form complex mineral skeletons, as in diatoms and radiolarians, spectacularly pictured in the nineteenth century by Ernst Haeckel. Just making the right proteins at the right times cannot explain such structures without many other forces coming into play, including the organizing activity of cell membranes and microtubules.
Most developmental biologists accept the need for a holistic or integrative conception of living organization. Otherwise biology will go on floundering, even drowning, in oceans of data, as yet more genomes are sequenced, genes are cloned and proteins are characterized.
I suspect that morphogenetic fields work by imposing patterns on the otherwise random or indeterminate patterns of activity. For example they cause microtubules to crystallize in one part of the cell rather than another, even though the subunits from which they are made are present throughout the cell.
Morphogenetic fields are not fixed forever, but evolve. The fields of Afghan hounds and poodles have become different from those of their common ancestors, wolves. How are these fields inherited? I believe, but cannot prove, that they are transmitted by a kind of non-local resonance, and I have suggested the term morphic resonance for this process.
The fields organizing the activity of the nervous system are likewise inherited through morphic resonance, conveying a collective, instinctive memory. The resonance of a brain with its own past states also helps to explain the memories of individual animals and humans.
Social groups are likewise organized by fields, as in schools of fish and flocks of birds. Human societies have memories that are transmitted through the culture of the group, and are most explicitly communicated through the ritual re-enactment of a founding story or myth, as in the Jewish Passover celebration, the Christian Holy Communion and the American thanksgiving dinner, through which the past become present through a kind of resonance with those who have performed the same rituals before.
Others may prefer to dispense with the idea of fields and explain the evolution of organization in some other way, perhaps using more general terms like "emergent systems properties". But whatever the details of the models, I believe that the natural selection of habits will play an essential part in any integrated theory of evolution, including not just biological evolution, but also physical, chemical, cosmic, social, mental and cultural evolution.
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This question generated many eye-opening responses from a "who's who" of third culture scientists and science-minded thinkers.
A book based on the 2005 Question What We Believe But Cannot Prove: Today's Leading Thinkers on Science in the Age of Certainty, edited by John Brockman with an introduction by the novelist Ian McEwan has been published by the Free Press (UK). The US edition follows from HarperCollins in March, 2006.