Introduction by Lynne Malcolm

Alan Saunders: How do animals think? Do they have consciousness? If your answer to that question is 'Yes', you're probably thinking of your pet dog.

But dogs are easy, they're domesticated, they more or less co-evolved with us; apes are easy, too, they're our cousins. But what about octopuses?

Octopus intelligence is going to occupy a lot of our attention in this special summer episode of The Philosopher's Zone.

We need to learn about the strange way in which the octopus brain works before we can move on to the philosophical implications of this and other forms of animal intelligence.

Hi, I'm Alan Saunders and we're ending 2011 and beginning 2012 with Peter Godfrey-Smith.

He's the Australian born Professor of Philosophy at the City University of New York. How though, did Peter come to be so interested in octopuses?

Peter Godfrey-Smith: It was partly as a consequence of meeting them. So I work in the US, as we say, but I come back to Australia a lot and spend quite a bit of time swimming around Sydney Harbour, and began to notice octopuses. And they're watching us, whether or not we're watching them; Sydney is a great place for octopuses, not just the blue-ringed octopus which is the one that people know about, but the larger octopus, which is the Gloomy Octopus. And I began watching them, and then trying to learn a bit about them and realised how little is known.

Alan Saunders: Why is it called the Gloomy Octopus, is that because of its disposition?

Peter Godfrey-Smith: It's because of its large and world-weary eyes.

Alan Saunders: Amongst the invertebrates, only the cephalopods (octopuses, cuttlefish and squid) have large brains. And in fact you said that meeting an octopus—you just said you were meeting octopuses when you were swimming—is like meeting an intelligent alien.

Peter Godfrey-Smith: That's right. It's probably the closest we'll get to meeting an intelligent alien. So as you said a few minutes ago, if we think about the animals that we normally interact with, that we think of as reasonably intelligent and perhaps having a kind of inner life, for animals like cats and dogs, chimps, dolphins also, these are all our cousins really, in evolutionary terms. So they're all—if we look at the common ancestor that we share with those animals, we're going back a fair way, and if we include birds we're going back quite a way to about 300 million years.

But if we then ask about our relatedness to the only intelligent invertebrates, the cephalopods, we're going back much, much further, perhaps 600 million years, really to the dawn of complex animal life. And since that time, our evolutionary paths have been quite independent. If you go back to that point and look in the sea at an animal that is both an ancestor of us and an ancestor of octopuses, it'll be a tiny little grub, swimming in the ocean with a very simple nervous system, nothing like the sort of complex behaviours of familiar intelligent animals.

So you have a sort of forking of the evolutionary path, you have a forking of the ways and down one path you get to us with one track of nervous system evolution, and down a wholly independent path you get this sort of outpost, or this island of intelligence among the invertebrates, which is the cephalopods.

Alan Saunders: And one of the differences between them and us is that their nervous system is less centralised than ours.

Peter Godfrey-Smith: That's right. So if you ask what are the basic design differences between the nervous systems of vertebrate animals like ourselves, and many invertebrate animals, not just octopuses but insects and worms and many other invertebrate animals, probably the first thing you would say is that we have a more centralised nervous system.

Even if you sort of set aside the question of just size, and just look at the layout, many invertebrates have what's called a ladder-like nervous system, which does look a little bit like a ladder. You have knots of neurons that are spread through the body and that are linked to each other in a ladder-like structure. And molluscs, octopuses and other cephalopods are molluscs, like clams and oysters, these tend to have a ladder-like nervous system, and what evolution has done with the cephalopods it has built a big nervous system on the plan that usually goes with these smaller nervous systems.

And one thing it's done, it has built a somewhat centralised nervous system, but because of the starting point and perhaps because of the different demands of their lives, the result is a less-centralised nervous system than a nervous system like ours. So the neurons of an octopus, and there are many neurons in an octopus, roughly 500-million, which is a lot; they are much less concentrated in what we think of as the head, they're scattered through the organism and in particular the majority of an octopuses neurons are in the arms themselves.

Alan Saunders: Well that's very curious. I mean obviously there must be neurons in the head, because it's got eyes in its head, hasn't it?

Peter Godfrey-Smith: That's right. There are eyes and there are big structures behind the eyes called the optic lobes, which are some of the smarter parts, it's thought, of the octopus's brain. That's the respect in which evolution has built something that's recognisable to us as a sort of brain inside a head, between the eyes, a big cluster of nervous complexity between the eyes. We do have that in octopuses, and that's where a lot of the smart stuff goes on, but there's this strange fact that the majority of the neurons are not there, they're scattered through the body.

Alan Saunders: And is it an exaggeration to say that an octopus has a brain in each arm?

Peter Godfrey-Smith: That would be an exaggeration, and each arm has a lot of neurons but that itself doesn't mean that much because they could all be controlled by a sort of central controller in the brain, and I was recently sent an email by an octopus biologist in Alaska, a guy called David Shiel. David once saw some octopuses being cut up for food while they were still alive and the arms were being put in a bucket, and the heads were being discarded and he said that from his vantage point, he could see the individual arms sort of crawling their way up the edge of the bucket, as if, like a whole organism.

Alan Saunders: All this suggests that octopus minds lack the cohesiveness that human minds have, but that's something that's generally said about animal minds.

Peter Godfrey-Smith: That's right. And I think if we're looking for first generalisations about the differences between non-human minds and human minds, something about cohesiveness and integration is probably a good thing to be looking at. So here's a nice example with the more familiar animal, birds. So with humans it's generally the case, I mean there are some interesting results to the side here, but it's generally the case that which eye you see something with, does not have many consequences for your downstream behaviour. But with birds, it's quite easy to teach a bird to solve a certain problem in a way in which only one eye is used, and then if you test the bird on that problem in which it is forced to use only the other eye, in at least some birds, (pigeons are the ones who've been tested here) they failed the test. So the picture you get from an experiment like that is that even with something similar to us like a bird, it looks as if there's less cohesiveness, less integration, less centralisation of intellectual processing, and octopuses are perhaps an extreme case of that, a case where you can see from the map of the nervous system that what nature has done is built a less integrated, less cohesive style of organism with respect to its intelligence.

Alan Saunders: So this presumably is why they are of philosophical interest. I mean philosophers studying the human mind used essentially to think about not just the human mind but a rather narrow sub-set of the human mind probably living in North Oxford, but octopuses provide a far more extreme example of the way in which minds might work.

Peter Godfrey-Smith: That's right. So if you ask a question in the following form, if you ask: 'What are some generalisations we might make about the nature of the mind that we would expect to hold every time minds evolved in the universe; not just our local parochial neighbourhood here, but wherever complex organisms with powerful information processing abilities arise; are there things we can say about every mind? Then probably octopuses and other cephalopods, they're still very imperfect cases to look at, because we are related to them; they have neurons just as we have neurons, the raw materials are quite similar, but they're far enough away from us that we can at least begin to ask these very general questions.

For example, we could ask questions about learning rules. So learning rules would have evolved independently in cephalopods and in vertebrates such as ourselves, so if we can both learn by reinforcement, by attending to the good and bad consequences of our actions, by having some behaviours reinforced positively and some reinforced negatively, if we can both do that and do that in the same kinds of ways, then that's something which evolution has done twice over. It seems to be a sort of basic design principle for minds, that you build something with trial and error learning. And it's true that cephalopods can engage in that kind of learning.

So you have a situation in which a similar kind of program if you like, or rules of design are seen in two separate experiments in the evolution of life on earth, our experiment and the octopus experiment. So if we ever do encounter genuine aliens from another planet, they will be more different again because they will presumably have no evolutionary connection with us whatsoever, they'll be more different we can suppose. But octopuses are the one actual world presently-known case that might give us some hints about a case like that.

Alan Saunders: On ABC Radio National, you're with The Philosopher's Zone and I'm talking to Peter Godfrey-Smith from Harvard University about animal intelligence and in particular octopus intelligence.

Peter, the American philosopher Thomas Nagel wrote a famous article called 'What is it like to be a Bat?' He assumes that there must be something that it is like to be a bat, but that whatever it is like to be a bat, the experience of being a bat is so irreducibly batty that we can't know what it is. Some people though have denied this, they actually think there is nothing that it is like to be a bat. Is there, do you think, something that it is like to be an octopus, or are there in fact given all these arms with neurons in them, are there several things that it is like to be an octopus?

Peter Godfrey-Smith: That's the big question. I don't have a confident answer, I'd love to have something very definite to say, and I don't know how we'll find out. I think here again, octopuses are a good case for the following reason:

One reason that people sometimes deny that non-human animals have a subjective inner life is the fact that they have this reduced cohesiveness, or reduced integration of their intelligent faculties. And if it's true that there's a relationship between the degree of integration of an animal's life and the question of whether it has a capacity for subjective experience, then octopuses are an important case because they have, at least it appears from the map of their nervous system, they have an especially decentralised and disintegrated nervous system. So that would provide some reason to doubt whether it feels like anything to be an octopus, if you think that there's this important connection between the integration of a nervous system and the capacity to have experience.

Now that if there is one that, as I say, I don't really know how to make progress on it. It's one of these questions where I suppose 20 or 50 years from now, something will have happened and we'll think, 'Oh, of course, right, that was always the key here'. But at the moment, I can't do a good job of even guessing how we might press on this problem in a really progressive way.

Alan Saunders: When you say don't know how to make progress here, are you saying that we don't know how to make scientific progress, or are we talking about philosophical progress? Are we talking about getting a philosophical grip on the issue?

Peter Godfrey-Smith: I wouldn't make much of a distinction between the two with respect to this question. So what we're asking is, is it something that feels like to be that animal? And we ask it often about animals like cats and dogs, and most of us are fairly confident that it does feel like something to be one of those animals. And I think in different ways we all encounter different kinds of doubt when we begin to look at animals that are further from us and that have smaller and simpler nervous systems than ours. Octopuses have a big nervous system but one which is profoundly alien in some ways.

So we ask the question and my personal hunch is that it does feel like something to be an octopus. But if someone denies it to me, I have a hard time at this stage, mounting arguments that I think of as convincing arguments.

Alan Saunders: There's another notion of consciousness: access consciousness, in which mental representations of the world may be poised for use in rational control of action, action or speech, but taking speech as a form of action, and a form of action unavailable to animals. Do animals, do you think, have that? Do they have access consciousness?

Peter Godfrey-Smith: I'm a little bit sceptical about the usefulness of that concept, the idea of access consciousness. So in philosophy at the moment, a lot of philosophers like the distinction between what they call phenomenal consciousness and access consciousness, where to be phenomenally conscious is to have the capacity to have experiences that feel like something, and access consciousness is as you said, having mental representations with a certain kind of relationship to the control of action.

I'm a bit sceptical about that for a couple of reasons. Here is a framework that I think I of as perhaps a better framework. So if we ask the question, does it feel like something to be an animal? I don't think of that as synonymous with a question about some kind of consciousness. Let's just take the example of pain. I look at an animal and I ask 'Does this animal have the capacity to feel pain?' Perhaps it's be being a bit idiosyncratic, but I don't think of that really as a question about a kind of consciousness, I think of it as a more basic question about whether an animal has certain kinds of feelngs. So that's sort of Question 1. Does it feel like anything to be this animal, where pain is an example of a kind of feeling?

Now that doesn't exhaust the questions we might ask about the mind and questions about consciousness or one category of further questions. Within neurobiology rather than philosophy, one framework that some people like very much at the moment is called the works-based theory of consciousness, which is a family of ideas that have the general form—we've been discussing this in some ways implicitly all along—which is the idea that the difference between animals with conscious information processing and animals with another kind of information processing, has to do with certain kinds of integration and certain devices that achieve integration. And one possible way I can imagine things coming out, is a situation which we say 'All these animals'—we give a list of certain animals—'it feels like something to be them.' But they don't have what we might naturally describe as conscious thought, because of the absence of a certain kind of integration in their information processing.

Alan Saunders: This is a bit of an aside, but you talked about feeling pain. What about suffering? If I come across a dog that has been chained up for a long while, possibly not fed, possibly regularly beaten and it whimpers when I approach and backs fearfully away from me, I would say that that animal was suffering, not just in the sense of suffering pain, but suffering. Now am I right in attributing that to the dog, or should I simply say 'Well, it's undergone pain and it's undergone repeated pain'?

Peter Godfrey-Smith: I think you'd be right, and this is an area where there is some work that establishes some useful bridging concepts between the human and the non-human case. So the example I have in mind is stress. So we think of stress as very much a kind of human thing, the stress of our working lives or something like that. But stress is a kind of biologically, not a universal, but something which is found recognisably in lots and lots of animals. So there's been a great deal of work on the stress response in primates such as baboons and chimpanzees.

There's also been some work on stress-like responses in fish, which are fairly distant relatives of ours. So stress is something which I think that's a concept we can use not just about humans, but in a fairly scientifically well-based way about non-human animals. And it's probably the case that if you look at the dog you are describing, that its chemistry, its blood-chemistry, will show a stress response which is identifiably similar to a human stress response.

Alan Saunders: Now the story our engagement with animal consciousness goes back as far as Aristotle, but the obvious place to begin the historical story is in the 17th century, with Rene Descartes. What did he have to say?

Peter Godfrey-Smith: Right, yes. Descartes had a view in which animals are machines, essentially, non-human animals are machines. And to his credit, he didn't just sort of say this as something which fitted into his story and which was not argued for, he did give fairly careful arguments. He argued that language is a really important divide between humans and non-humans, and that the human capacity for language requires that we be more than machines, but the things that animals can do, which don't include the use of language, are things that could in principle be explained mechanistically. Now that's an argument which I think did make a good deal of sense in Descartes' time. At the present time the idea that language is intrinsically non-mechanisable is a much less likely idea.

Alan Saunders: Now Descartes' arguing for an absence of animal consciousness on grounds of the dissimilarity between animals and us. But you can also argue for an absence of animal consciousness on the basis of certain similarities between animal behaviours and behaviours which can be conducted unconsciously by humans. It's been argued that all animal behaviour can be assimilated to the non-conscious activities of humans, such as driving while distracted, driving on auto-pilot. I'm unconvinced by this. What do you think?

Peter Godfrey-Smith: I'm also unconvinced. It's an attempt to say something that bridges the human and non-human case and you can see reasons for saying it. But one reason you might resist this is the following:

So attention is a phenomenon which we're familiar with from the human case, and attention is something which is probably the simplest summary of what's missing when a person is driving on auto-pilot, they aren't attending to the act of driving. Now I think it's reasonable to think that for animals too, there's a distinction between things that they do while attending and things that they don't. So when one's interacting with as it might be a dog, or in fact an octopus—this happened to me the other day—you can sometimes see the signs of attention. The animal acquires a focus on a particular aspect of their surroundings which is—it's a definite move the animal makes. It's now attending to this. So the idea that animals live are sort of auto-pilot across the board, I think of as—at least one thing missing from that picture is the distinction between attention and its absence, which I think is visible in the animal case as well.

Alan Saunders: John Searle, the American philosopher says, 'I do not infer that my dog is conscious any more than that when I came into this room, I inferred that the people present are conscious; I simply respond to them as is appropriate to conscious beings. I just treat them as conscious beings and that is that.' Perhaps you can do that with dogs—can you do it with octopuses?

Peter Godfrey-Smith: Right. You can't. It's a nice illustration of a crucial difference, so with dogs as you said earlier, we've co-evolved with them in many respects, and our behaviour's integrated with theirs, in such a way that Searle's comment makes some sense. But just as if we met an alien, that would not be the case and we'd have to sort of start from scratch and ask ourselves, Well what are we saying when say that this thing has beliefs, that it has feelings and so on, and what evidence would show us that it had those things?

We have to ask those questions in the case of the octopus, from scratch. It's not the case that we're dealing with an animal whose behaviours are integrated with our habits in a way that can make the question less problematic.

Alan Saunders: Well Peter Godfrey-Smith, thank you very much for joining us this week.

Peter Godfrey-Smith: It's a pleasure.

Peter Godfrey-Smith is Professor of Philosophy at the City University of New York.

Lynne Malcolm back announces the program