David Bohm was an eminent quantum physicist. As a young man he worked closely with Albert Einstein at Princeton University. With Yakir Aharonov he discovered the Aharonov-Bohm effect. He was later Professor of Theoretical Physics at Birkbeck College, London University, and was the author of several books, including Causality and Chance in Modern Physics 1 and Wholeness and the Implicate Order. 2 He died in 1992. This dialogue was first published in ReVision Journal, and the editorial notes are by Renée Weber, the journal’s editor. 3
Bohm: Suppose we look at the development of the embryo, at those problems where you feel the present mechanistic approach doesn’t work. What would the theory of morphogenetic fields do that others don’t?
In each moment there’s a selection of which potential is going to be realized, depending to some extent on the past history, and to some extent on creativity.
Sheldrake: The developing organism would be within the morphogenetic field, and the field would guide and control the form of the organism’s development. The field has properties not just in space but in time. Waddington demonstrated this with his concept of the chreode [see Fig. 5], represented by models of valleys with balls rolling down them towards an endpoint. This model looks mechanistic when you first see it. But when you think about it for just a minute you see that this endpoint, which the ball is rolling down the valley towards, is in the future, and it is, as it were, attracting the ball to it. Part of the strength of this model depends on the fact that if you displace the marble up the sides of the valley, it will roll down again and reach the same endpoint; this represents the ability of living organisms to reach the same goal, even if you disrupt them – cut off a bit of embryo and it can grow back again; you’ll still reach the same endpoint.
Bohm: In physics the Lagrangian law is rather similar; the Lagrangian falls into a certain minimum level, as in the case of the chreode. It’s not an exact analogy, but you could say that in some sense the classical atomic orbit arises by following some sort of chreode. That’s one way classical physics could be looked at. And you could perhaps even introduce some notion of physical stability on the basis of a chreode. But from the point of view of the implicate order, I think you would have to say that this formative field is a whole set of potentialities, and that in each moment there’s a selection of which potential is going to be realized, depending to some extent on the past history, and to some extent on creativity.
Sheldrake: But this set of potentialities is a limited set, because things do tend towards a particular endpoint. I mean cat embryos grow into cats, not dogs. So there may be variation about the exact course they can follow, but there is an overall goal or endpoint.
Bohm: But there would be all sorts of contingencies that determine the actual cat.
Sheldrake: Exactly. Contingencies of all kinds, environmental influences, possibly genuinely chance fluctuations. But nevertheless the endpoint of the chreode would define the general area in which it’s going to end up. Anyway, the point about Waddington’s concept of the chreode, which is taken quite seriously by lots of biologists, is that it already contains this idea of endpoint, in the future, in time; and the structure, the very walls of the chreode, are not in any normal sense of the word material, physical things. Unfortunately Waddington didn’t define what they were. In my opinion, they represent this process of formative causation through the morphogenetic field. Waddington in fact uses the term ‘morphogenetic field’. Now the problem with Waddington’s concept is that, when he was attacked by mechanists, who maintained that this was a mystical or ill-defined idea, he backed down and said, well, this is just a way of talking about normal chemical and physical interactions. René Thom, who took up the concepts of chreodes and morphogenetic fields and developed them in topological models (where he called the endpoints ‘morphogenetic attractors’), tried to push Waddington into saying more exactly what the chreode was. Waddington, whenever pushed by anyone, even René Thom, backed down. So he left it in a very ambiguous state.
Now Brian Goodwin and people like him see chreodes and morphogenetic fields as aspects of eternal Platonic forms; he has a rather Platonic metaphysics. He sees these formative fields as eternally given archetypes, which are changeless and in some sense necessary. It is almost neo- Pythagorean; harmony, balance, form and order can be generated from some fundamental mathematical principle, in some sort of necessary way, that acts as a causal factor in nature in an unexplained but changeless manner.
The difference between that and what I’m saying is that I think these morphogenetic fields are built up causally from what’s happened before. So you have this introjection, as it were, of explicit forms, to use your language, and then projection again.
Each moment will therefore contain a projection of the re-injection of the previous moments, which is a kind of memory; so that would result in a general replication of past forms
Bohm: Yes. What you are talking about – the relation of past forms to present ones – is really related to the whole question of time – ‘How is time to be understood?’ Now, in terms of the totality beyond time, the totality in which all is implicate, what unfolds or comes into being in any present moment is simply a projection of the whole. That is, some aspect of the whole is unfolded into that moment and that moment is just that aspect. Likewise, the next moment is simply another aspect of the whole. And the interesting point is that each moment resembles its predecessors but also differs from them. I explain this using the technical terms ‘injection’ and ‘projection’. Each moment is a projection of the whole, as we said. But that moment is then injected or introjected back into the whole. The next moment would then involve, in part, a re-projection of that injection, and so on in-definitely.