Physics of Consciousness: Sean Carroll Source URL: https://www.closertotruth.com/interviews/54817 Transcript - Long Robert Lawrence Kuhn: Sean, consciousness has been one of my focuses of life. My doctorate's in neuroscience because I wanted to try to understand consciousness, of course, one had very little to do with the other at that point, but I've continued to focus on it as – as perhaps the – the, ah, key to under – to really understand reality. Now, you may disagree with that. I know you're a radical physicalist, so how do you deal with consciousness? Sean Carroll: I think that consciousness is a way of talking about the physical world, just like many other ways of talking. It's one of these emergent phenomena that we find is a useful way of packaging reality, so we say that someone is conscious of something that corresponds to certain physical actions in – in the real world. I don't think that there is anything special about mental properties. I don't think there's any special mental realm of existence. I think it's all the physical world and all the manifold ways we have of describing it. Robert Lawrence Kuhn: Okay. Give me another example of an emergent phenomena. Sean Carroll: Well, the classic example of an emergent phenomenon is the fluid description of the air around us. The fact that even though it's made of discrete particles—atoms and molecules—we talk about it as a continuum with a pressure and a temperature and stuff like that. It's a – it's a macroscopic coarse grain view. Robert Lawrence Kuhn: Great. Great example. The wetness of water would be something similar. Okay. Now, I would believe, ah, that consciousness is a qual – qualitatively different from that because there is a, um, there – there is something that is like to have the feelings that I'm seeing. You call it an internal movie, whatever you want to call it, that the phenomenology of – of – of this is – is a – a radical difference from the – getting the wetness of water from individual molecules or the fluidity of air. Sean Carroll: Right. And— Robert Lawrence Kuhn: You must disagree with that. Sean Carroll: I do disagree with that. Uh, I think there is this – there is an irreducibility but it's not in the reality, it's in how people talk to each other about it. I – I – and I – there's – there's something that— Robert Lawrence Kuhn: But you see it. You live it. You feel it. Sean Carroll: Of course. That's right. And [Crosstalk] describe it in physical terms perfectly well. When – when you say like—[Crosstalk] I now have experienced the, ah, redness of red. I think that that is a set of words that can be mapped on in a very direct way to certain physical things happening in my brain. Robert Lawrence Kuhn: Oh, nobody doubts that. There's— Sean Carroll: There are people who doubt that, but yes. Many people do not doubt that. Robert Lawrence Kuhn: Okay. Sean Carroll: And I think that's all there is. Is – is [Crosstalk]— Robert Lawrence Kuhn: At least among – at least among my friends nobody doubts that. Sean Carroll: You know, when you talk about the existence of a cat, you know, this is – this isn't a category, it is not to be found in the fundamental laws of physics, a cat. A game of basketball is not to be found because they're useful categories for describing the world. I think that consciousness, self-awareness, experience, intersubjectivity, very useful categories for describing the world. \[page\] Robert Lawrence Kuhn: No, but you know some physicists, ah, see consciousness as – as sitting below, ah, the wave function, not just part of the wave function but actually sitting below it as the most fundamental thing [Crosstalk]... Sean Carroll: Some physicists deny global warming. [Laughter.] I mean, some physicist, it's not a very good beginning to almost any sentence. Robert Lawrence Kuhn: Okay. Alright, I accept that. Um, so – but – but with – with consciousness your, um, one philosopher has said that consciousness, ah, is an output of the brain like urine is the output of the kidneys. Is that something you would subscribe to? Sean Carroll: It's – ah, no, I don't – I'm not sure I would use that exact metaphor. I mean, again, I think it's a very, very useful construct at a higher level of description, right? I can't imagine doing without consciousness as a way of talking about the world. I know what it means when people say I'm conscious of this, I know what it is like to be that. These – these are real ways of describing the underlying physical reality. Robert Lawrence Kuhn: When you're saying I'm conscious of it, that's sort of a – a – a – an English locution that means I'm aware of something, but – but it – but you could – you could almost be conscious or aware of something in a – in – in a – in a – in a mechanical or a zombie like way in terms of behavioral reaction. But I'm talking about this – the – the phenomena that we all feel seems so radically different from anything that you see in the brain. I mean, I dealt with that. You deal with the probing of electrodes and electrochemistry and, ah, and the genetic expressions. Do you believe that the – the phenomen – phenomenology of what we see is, in an identical theory sense, two descriptions, like ah, the morning star or the evening star is – is the same as Venus. Sean Carroll: Yes, that's right. Robert Lawrence Kuhn: Is the same thing. I'm just calling it by different – because I didn't know that they were the same. Sean Carroll: Absolutely. And I think that actually, to me, zombies, the idea of the philosophical zombie, something that acts in exactly the same way as a conscious creature but just lacks the consciousness, lacks that inner subjective experience, is a great argument for my position in the sense that it's very hard to really take self consistently this idea of the philosophical zombie because if you met a zombie you ask them what are you experiencing right now. They would tell you exactly the same thing that a regular person would say. And – and you say, well, at least I know I'm not a zombie. Do you really know that? Of course, you're telling yourself you're not a zombie. You're experiencing. But so, would a zombie. A zombie would say they're not a zombie. I think that there's really no way of boiling that thought experiment down to a consistent holding of the idea there could be something that physically acts exactly like me, yet lacks an important element of consciousness. Robert Lawrence Kuhn: The zombie would say that I'm not a zombie and describe the inner feelings, but would still be a zombie. SC: That – well that – that is the – that is the proposal [Laughter] and I'm – I'm just pointing out how – how silly it begins to sound— Robert Lawrence Kuhn: Okay. Sean Carroll: —because they would be sincere. Robert Lawrence Kuhn: Okay. Look, I think anything— Sean Carroll: They would really think they're experiencing it. Robert Lawrence Kuhn: [Laughs.] They would really say that they— Sean Carroll: Why would they lie? Robert Lawrence Kuhn: —it – it would be – it's – it's sort of a behavioral reaction, you know, it – it – it's sort of an input output. Sean Carroll: That's right. And the difference between me and someone who thinks that there's something phenomenologically different about consciousness is that that is all there is. \[page\] Robert Lawrence Kuhn: So, an implication of your view, I – I think, is that you have to be 100% sure that at some, ah, time in the future, with future technologies, some people would say 20 or 100 years, some people may say a thousand years, you would be able to upload your, ah, individual first-person consciousness to a – another medium, whether it's non-biological or another person. You – you would have to be 100% sure of that. Sean Carroll: Well I'm not 100% sure— Robert Lawrence Kuhn: Why wouldn't you be? Sean Carroll: —of anything in the world. I'm not 100% sure that the universe is [Crosstalk]. Robert Lawrence Kuhn: Well, no – given – come on – given your presupposition as a radical physicalist to consciousness, that's what – that's the given. Sean Carroll: Yeah. I see no – I think the way I'm happy to say it is I see nothing special about an organic human being that could not be duplicated to arbitrary accuracy. Robert Lawrence Kuhn: Or – or if there were something then you could just duplicate it in an organic – you could create a human being. Sean Carroll: And we all know there are thought experiments so we – we do believe, most people believe, that I could take out one neuron from my brain— Robert Lawrence Kuhn: Okay. Alright, no, we've been through that. Sean Carroll: —replace it with an electronic brain. Robert Lawrence Kuhn: Right, right. Sean Carroll: And then I still just as conscious— Robert Lawrence Kuhn: Right, right. Sean Carroll: And what happens when I take out two and to me that – that's not even an issue. Like, yeah, sure, just as conscious all the way down.