Is emergence just mumbo-jumbo?

David: Can I ask you…? We’ve been using the word ‘science’: what are the qualities of science? I mean, I’m thinking of reductionism, determinism, those things. When you think of science, is it that kind of reductionistic science, or…?

PA: I think the core of science is imagination in alliance with honesty. Just to be honest without being imaginative means that you’re not doing very good science; being imaginative without being honest means that you’re being a poet.

David: That’s the poets struck off the list!

PA: I think the combination of the two is really the core of being an effective, interesting scientist.

David: Okay.

PA: Then I think you then have the distinction between reductionism and emergence.

David: Yes, what’s…?

PA: I think the easy part of science is reductionism: dismembering the butterfly in order to find its atoms. But the difficult part is reassembling the simple ideas that you’ve developed and creating the butterfly out of the atoms and seeing that an idea of beauty emerges from that.

David: Yes, when you’ve reduced it down to its bits, you understand how all the bits work. But even if you do understand that and you put all those bits back together, if all you understand are the rules for the individual bits, you’ll have left out the emergent rules. Once it becomes the whole system, once it becomes the butterfly, there are new rules which emerge at the level of the butterfly and have very little to do with the level of its atoms. Does that work for you or is that mumbo-jumbo?

PA: That’s mumbo-jumbo. I mean, all defeatism is mumbo-jumbo, basically.

David: Why is it defeatism?

PA: Because it suggests that there’s something beyond your understanding of the entities that make up the butterfly.

David: Why should that be a defeat, though?

PA: Well, because we hope through the scientific method that we will understand absolutely everything. It’s a wonderful challenge that the world is out there in all its complexity. We little humans are tinkering with understanding little bits of it, but we’re gradually migrating towards an understanding of the whole, and that includes understanding how the individual entities collaborate into producing a system. I mean, it’s a real challenge.

David: Yes, and in its own way, a very powerful and beautiful one. I mean, everything we’ve got scientifically is from that method. But I don’t see why it’s a defeat to say in addition to the rules that govern the individual parts there could be entirely scientific rules which operate at the level of the system.

PA: Yes, but we’ve got no need for them at the moment. There are rules that operate only when you have congregations of atoms and molecules for which it would be meaningless to talk about the property of a single atom: temperature. What do you mean by ‘the temperature’ when you’ve got a single atom? It can’t mean anything.

But what you mean by temperature is the distribution of myriad molecules over the available energy levels following a particular form. Now, I can understand that. You might say that temperature, therefore, is an emergent property. And in a sense it is, but I also understand it in terms of what is going on at the level of a collection of individual molecules. So I don’t see that there is any real difference between an emergent property like temperature, which I claim can be understood in terms of the behaviour of individual molecules, and the emergent property of being a butterfly.

Ard: Really? So how about…?

PA: I mean, I’m an optimist. And I can’t stand philosophers because they’re all pessimists! So don’t be defeatist! Be optimistic!

David: When we talked to George Ellis and others who are keen on emergence, one of the reasons they’re keen on it is, they say, ‘Look, with reductionism everything is caused from the lowest level.’ Whereas, with emergence, they say you then get what they call downward causation, so the system itself then has an effect on its parts. Some things in the universe are not caused by just the rules which guide the atoms and the chemicals…

PA: Well, that’s nonsense, isn’t it?

David: Is it?

PA: I think it must be. It’s a mechanical universe. It might be a quantum mechanical universe, but effect follows cause even in a quantum universe.

David: Yes, and they’re saying sometimes the cause is at the higher level and causes an effect lower down; that it’s not all cause coming up from the atoms.

PA: Well, I can see that if I have a particular thought that it might make me sweat through embarrassment, for example.

David: Yes. That’s precisely it.

PA: So there is a kind of downward…

David: Right, so they’re saying an emergent level of the universe is the level of thought.

PA: Yes.

David: And that once it’s in the universe, then a whole new set of rules emerge which have causative power: they cause things to happen. So suddenly it’s not just that the atoms cause a reaction in your kidneys which make you think that you’re thirsty and that you have a thought. You see what I mean? It’s a radical challenge to reductionism, isn’t it? They think it is, and I’m inclined to agree it is.

PA: Science fiction writers often play with ideas like that as well. It’s quite interesting to see the way that writers of fiction think.

David: Yes, but I’m asking you as a scientist whether you think there’s something to it. Because you said, ‘Well, I could see an idea…’ It seemed like you were entertaining this notion might be right.

PA: Only to amuse you!

David: Okay, that’s me put down. But not to amuse me, what do you think of it? Because people like Noble and Ellis and others, they say, ‘Look, this is the future of science. This is a revolution. Yes, there’s causation, reductionist science, but there’s this other kind: the downward causation from emergence.’ They see this as a real scientific endeavour.

PA: Yes. Well, obviously, because it’s a scientific endeavour, you shouldn’t dismiss it out of hand. You should explore whether there are consequences, whether it’s testable and whether there is any… what we loosely regard as truth.

David: Loosely regard?

PA: And if there is even the hint of evidence for it, then it’s worth pursuing, because science doesn’t dismiss out of hand, or at least shouldn’t dismiss out of hand.

David: What’s your feeling about it as a scientist?

PA: What does my gut say, rather than my brain?

David: Yes.

PA: Worth thinking about, but not worth investing in.

Ard: That’s your investment advice? Sell!