video
Topic Series
John Searle
Robert Lawrence Kuhn: Levels of Nothing
Sara Imari Walker on Physics, Emergence, and Life on Other Planets
Greg Epstein on Technology, Morality, and Non-Religion
David Papineau on Consciousness, Physics, & the Mind-Body Problem
Or Graur on the Big Bang and the Physics of Galaxies
Ned Block on Perception, Cognition, and Consciousness
- Robert Lawrence Kuhn
- John, I have spoken to several very distinguished philosophers who argue passionately that there really is a special substance that makes us a person, that the person is not all material. That there really is some soul, spirit, there's a religious connotation that may have different forms, but essentially it's a – a different kind of stuff. Uh, how – how do we begin to address those kinds of arguments?
- John Searle
- Yeah. Well, to begin with, the people I know who hold this sort of view hold it for some religious reason. Uh, they have a – an extra agenda – they have a hidden agenda. And we should address that agenda. But let's leave that out for the moment. Let's forget about the fact that they believe this because of a belief in God, and let's ask ourselves, do we have any reason to suppose that in addition to all the phenomena of our conscious life, all the stuff that we're aware of, there is something else – the soul – in which all of this occurs. And I have to say, one, I have never seen any argument, any solid argument for the existence of the soul in addition to the obvious facts of a consciousness. And, two, it isn't just that there's no argument, but it's hard to make sense out of it. How would it fit in to what we know about the physical world? See, I think the central problem in philosophy right now is to give an account of how – what we know about the physical world, the world of – of atomic physics and molecular biology and evolutionary biology, how that's consistent with what we know about ourselves as conscious, mindful, rational agents. And that's what I'm trying to do, is make those consistent. I don't see how you can do that if you postulate the soul.
- Robert Lawrence Kuhn
- Well, let – let's try to look at and – and try to take all their arguments and try to get some generalized – what are some of the characteristics? And the – the primary characteristic seems to be an analysis that when you do all the analyses, there's always something left over. You can do all the physics, all the biology, and – and – and do it and – and – and postulate, you know, a thousand years into the future and you know everything. We know every molecular orientation and 3-dimentional structure of every protein and every neuron. And we can simulate it on a super quantum computer.
- John Searle
- Um-hum.
- Robert Lawrence Kuhn
- We still will have left something out.
- John Searle
- Yes, that – that – the reference to the computer though gives the game away because the operations of the computer are defined purely formally or syntactically typically stated in terms of symbol manipulations. And we know that's not enough. But let me vary what you said slightly. Let's suppose we had a perfect science of the brain. We know everything there is to know about the brain. We know how the brain causes all of our conscious states. We know how they're realized in the brain. We know how memory works, how vision works, how desire works, how desire works to produce intentions to produce actions. We know how all of that goes on in the brain. Then I want to say, there isn't anything left over. Or rather, there's one thing left over and that's the notion of our self as a self. But I think, if I'm imagining a perfect science of the brain, I – I think that would also be accounted for. In fact there are – is a lot of research on precisely this question on how the brain gives us a sense of ourselves as selves. So I am – I am claiming that a perfect science of the brain that's consistent with the view I call biological naturalism that says all of our conscious life is caused by brain processes and realized in the brain, that that would give us an answer to all of the questions we – that are meaningful questions. And you don't have anything left over, which the hypothesis of the soul would be able to account for.
- Robert Lawrence Kuhn
- Well, having something left over is key to that whole argument.
- John Searle
- Um-hum.
- Robert Lawrence Kuhn
- And that something left over is the inner experience – the first person experience of the so-called qualia, that what pink in your shirt means to me and how I feel about that pink.
- John Searle
- Yes, but you see this is what – I mean, this is the traditional mind/body problem. And what I'm hypothesizing is that we imagine a science, which is such that that problem has been solved. We know exactly how the experience of pink is caused in you by a sequence of events that begins with the photo receptor cells and goes through a very long and complicated series and processes in your brain, and winds up in a – in – in – in the cortex with you having a visual experience of pink. If we had that story, we know exactly where it happened and how it went on, then you don't have any room left over for the soul. See, there are two different – let me just summarize this as a crucial point. There are two different claims at issue here. One is a description of the neurobiological processes isn't yet a description of consciousness. I agree.
- Robert Lawrence Kuhn
- Right.
- John Searle
- You have to have a causal story about how the neurobiology causes consciousness. But that – quite a distinct point is, if you had a perfect neuro – account of neurobiology and how it causes consciousness, then you would still need the soul because there would be something left over. And I don't see that anything has been left over.
- Robert Lawrence Kuhn
- But – but jumping that gap in – in – in the first question, you did that very quickly but –
- John Searle
- Yeah.
- Robert Lawrence Kuhn
- We may be able to trace every circuit so that if these neurons are firing it's pink, and if those are – if those are firing it's a little reddish more, and so everything is very clear, but still you're leaving out what it feels like to – to experience that.
- John Searle
- Yes. No, I agree with that, and that's essential to my whole account –
- Robert Lawrence Kuhn
- Okay.
- John Searle
- – is that the description of the third-person neurobiology is not yet a description of the first-person qualitative experience.
- Robert Lawrence Kuhn
- Right.
- John Searle
- This is what I sometimes put by saying, consciousness is causally reducible. You can give an entire causal account of how it works and how it goes on in the brain. But it's not ontologically reducible in the sense that you don't show that it doesn't exist. Ontologist just means having to do with existence. The existence of consciousness itself is not reducible to third-person processes. But, and now this is the key point why I part company with these guys is, the existence of consciousness does not imply the existence of a soul.
- Robert Lawrence Kuhn
- Yeah, and they would say that your very honest differentiation between causal reduction, which can be done from consciousness to brain, but not ontological reduction – you cannot reduce consciousness, to – to anything, to – to a third-person description, that very honest approach is just the – the – the proof that there is something extra that you need – something beyond the physical world.
- John Searle
- Yes. Yet – and now I think we're now confronted with the traditional vocabulary. The vocabulary of the physical world and the mental world was designed to be mutually exclusive. And what I'm urging is, forget about the damned vocabulary and just ask yourself how it works in real life? And the way it works in real life is these neuronal processes in the brain cause conscious states. It's all biology. You have a set of biological processes that cause another biological phenomenon, consciousness. It's when you bring in the traditional Cartesian vocabulary: but is it really mental or is it really physical, and isn't it something apart from the, from the physical if it's irreducible – ontologically to the physical? Forget about the vocabulary. Just ask how it works. And we know enough about the brain to know that all of these states are caused by processes in the brain. So the temptation is to think: well, once you grant that there is this irreducible subjective qualitative stuff, then you're in bed with Descartes. And you might as well go the whole hog and embrace the soul. I don't think that follows. I think that you – if you just describe the facts and stick to the facts, then you get an account of consciousness, which is consistent with what we know about nature and what we know about biology, but which does not force you to postulate some mysterious entities that are not part of the physical world. By the way, let me go on the attack on one point. None of these guys who think there is a – a separate mental substance that functions causally in the universe, has ever been able give an account of how that's supposed to be consistent with the conservation laws. That is, is there supposed to be some spiritual energy that comes in and – and shakes the axons and the dendrites. I – I've never seen an account of that. And where does the spiritual energy come from? How is it consistent with the basic fundamental principle of physics, the conservation principle?
- Robert Lawrence Kuhn
- Here's what they would say. They would say that you are presupposing that the world – all there is is only the physical world. And you can just as well suppose, and a lot of this has a religious tradition, that there is a spiritual world, there is a God, and that everything that they say about consciousness is more consistent if you assume from the beginning that there is a physical world and a spiritual world.
- John Searle
- Yes, if you assume the – the existence of a spiritual world, if you assume dualism as an – an axiom, then the fact that your results are inconsistent with what we know about the world isn't going to bother you. I mean, all we can do in logical argument is show the price you pay for holding a false view. Now I am saying that this is a false, or perhaps incoherent, view on dualism. And one symptom of that is it forces us to deny perhaps the most fundamental but certainly one of the most fundamental facts that we know about the world from physics, namely the conservation of matter and energy. You have to suppose that there is a spiritual energy that's infused into the system from outside. And if you're willing to say, well I'm perfectly happy to give up the past three hundred years of science, then I have nothing to – to say by way of refutation. All I can do is show you the cost of maintaining this view.