¶1Miles. Hello. >> Hello. Can you hear me, Ralph? >> Yes, I hear you perfectly.
¶2Am I coming through? Okay. >> Yes. Let me Yeah, you actually sound fantastic and the video quality is great. >> That's That's great to hear.
¶3I I have a high quality podcasting mic that I was given when I recorded uh something last year, but I'm on a new laptop because I left my much better laptop on an airplane. So, I wasn't I wasn't sure how good the camera would be for this, but it seems to be okay. >> So, is that laptop gone forever? >> Oh, it it's gone forever. Yeah.
¶4Yeah. They they told me they told me at Heathrow uh I could get it through Lost and Found. I knew I knew it was in the pocket on the plane the moment I got through uh uh passport control, but no, it's I mean, I hope someone's enjoying it somewhere. Um >> I see. Okay.
¶5Well, that sucks. I'm really [laughter] sorry about that. U So, how are you? How are things? Um I'm sorry it took so long to bring this together.
¶6I've been excited to speak to you. Um but I know we've that I anyway have canceled it several times. So, thank you for being patient with me. >> No problem at all. No, I and I I at least one or two of those times it was uh I who asked to postpone.
¶7Uh but I'm really excited to be uh on your show. Yeah, I've I've listened to a whole bunch of episodes and I think it's really brilliant. So, so it's a privilege to be here. >> Um, and yeah, I'm doing I'm doing real well. I've just uh as I guess you know, I've just started a uh Lever Hume Fellowship uh based here in New York um at both forom and NYU.
¶8So, it's it's a great town for philosophy, philosophy of mind. Uh it's an amazing town to be in in all sorts of other ways. So, so yeah, I'm I'm doing great. >> And what does that fellowship afford you? Like not like how much does it pay you, but what do you have to teach for it?
¶9Does it just give you kind of unrestricted time to research? What what does it look like? It >> it's it's a year's time to focus on research. So, so the Lever Foundation, they they cover a replacement for me at Lincoln um to to cover my roles there, apart from graduate teaching, which I continue to do. Um, and it provides a little extra uh in research funding which um is just going on accommodation here because it's a little more pricey in New York than in rural England.
¶10>> That's completely fair. So, one of the questions I wanted to start out with was not so much specifically on the topic of philosophy of mind, but just a more personal note is um what originally got you interested in philosophy generally and philosophy of mind specifically like what was the origin story there? >> Well, um there there are two answers to the original interest in philosophy. What one answer is um when I was a teenager uh I wasn't I wasn't a very attentive student and that was reflected in my grades which were pretty embarrassing but I I got I got very into um uh art. I did the fine art A level and I was thinking I would I wanted to go to a art college but just in my final year I I happened to take an RS religious studies class which involved a lot of philosophy and I became more and more interested in it.
¶11I started becoming a much more attentive student um only only a little too late and I ended up switching my switching my plan on the basis of that but I I also have some family background in this. So um neither of my parents was was an academic but both of them uh did PhDs in philosophy and were interested in in that as well as literature and the life of the mind more generally. So I actually I can remember being in like the garden uh one summer as probably like a 5-year-old and my father explaining to me Hume's problem of causation uh and finding this very interesting. So in a in a way I' I've ended up doing something kind of um uh uh boring and followed in in uh the the family it's not quite the family trade but followed in my parents footsteps in in um [clears throat] uh taking this up as as my major uh interest in life and then and then philosophy of mind. I actually I did an undergraduate course in philosophy of mind at the University of Reading which was um it in in some ways I found it very alienating because uh I got the impression that everyone is a kind of Vickensteinian behaviorist or a kind of eliminativist materialist or something along those lines.
¶12And these these positions seemed outrageously implausible to me and I I found myself quite frustrated with the class. I I it didn't make me want to do philosophy of mind, but it got me thinking about it. And over the years, I went then over to Oxford to study ancient philosophy. I started to think, no, I really want to get to the bottom of this. What what's going on?
¶13How how how have people ended up embracing with such confidence positions that sound at face value to me really um difficult to make sense of. Um, so it it was kind of it was kind of out of a hostility to philosophy of mind that I ended up uh uh going into it. And now now I love the subject and uh I have great admiration for for uh my opponent's uh arguments and ideas even even where I do disagree with them. >> Now I would have thought that eliminativism specifically would be a radical minority. If if I understand it, this is the thesis that like mental states don't exist at all.
¶14It's even stronger than saying that they're identical to physical states, like states of your brain. It's it's the strongest view you could take. And just to say there just are no mental states whatsoever. They're not even identical to physical states. They just don't exist.
¶15I thought that was like 1% of philosoph like like just a radical minority. Am am I mistaken about that? Or have have things changed to the present day? I think it's true that I came away with a somewhat skewed impression of the field. I also think it's the case that it's there are many theorists who are hard to pin down because what it means to say there are really no mental states um h has to be has to be clarified in some way.
¶16So, so two two things you could say about this would be like uh that the classic eliminists would compare their position to replacing the theory that people are possessed by demons to the theory that they undergo some kind of uh mental uh illness. And um we would you know one would naturally express that by saying oh yeah there is no demon possession but that doesn't mean that you're saying people don't suffer greatly and exhibit all the behaviors that were previously referred to as demon possession. So they say like you know it's not it doesn't have the uh plainly false consequence denying the existence of possession word and and Daniel Dennis in in the start of cognit consciousness explained has a has a similar kind of um story about what if animals turned out to all be uh robots with fur or feathers on them. Well, you could express that by saying animals don't really exist or by saying animals are completely unlike what we've previously took them to be. And um yeah, so it so there are many positions that do entail what what I would call eliminativism, although there are stories that can be told about why they they might not be as as crazy as I I think they actually deeply are.
¶17>> Yes. Because I would say that if you did discover that animals had no subjective states of consciousness, that would still be a radical revision to what we take ourselves to know about the world. Whether you want to call that learning animals don't exist or just radically revising the concept. This is still a huge shift, an alteration to our kind of basic assumptions about the world. So I would >> Yeah.
¶18Yeah. That's that's right. I think then it would say it's just like there's a version of this view which is a radical shift in our assumptions about the world and then there is a version that even he would admit is uh self-evidently false and he he thinks he's he thinks he's only saying the former. >> So is eliminativism the same thing as what I see floating around Substack uh of illusionism? And if it's not, what is illusionism?
¶19I I think it's uh probably useful to say that illusionism is a strategy used by positions that are at least in a a useful sense eliminativist. Sorry, you you could um you illusionism is a theory about why we are strongly inclined to adopt false beliefs to the effect that we have mental states of a certain kind, say subjective phenomenology. Um and uh that theory is only going to be useful to someone who thinks that that we don't have those kinds of u mental states. So you're a limitist about something. Um but you could be an eliminist and say, "Oh, no.
¶20The reason why people uh falsely believe they have subjective phenomenology isn't because of some uh deep-seated illusion embedded in our cognitive architecture. I it's because um they were taught that they had it by uh uh priests and teachers or something, right? Or or or they're just very stupid and they don't see the truth. Um right, that would be okay. >> That is very helpful.
¶21Um >> I'm tempted to let me let's keep going on this line and then we'll circle back to the bigger picture. >> Sure. >> Because I have you in front of me and I've had these questions in my head for a long time. So, one of the corrections someone in the comments on a video I did with another YouTuber about philosophy of mind, they said, you know, illusionism is not the denial that consciousness exists. It's generally taken to be restricted to phenomenal consciousness.
¶22So, maybe this will be a good way to start helping us um cash out the the the terms mental versus physical, and we'll get at the mindbody problem. What is phenomenal consciousness in relation to consciousness more generally? Yeah. So I I h can only say about this what is standardly said by uh everyone which is that uh phenomenal consciousness refers to uh what is it what it is like to be uh a a being a creature that undergoes phenomenal states such as seeing patches of color in your visual field experiencing pain in your jaw etc. Um, that's of course Thomas Nagel's famous famous uh terminology from his paper, what what what it's like to what what's it like to be a bat.
¶23Um, and that we can distinguish this from uh one or more behavioral or functional uh ways of understanding or or definitions or conceptions of consciousness. Um, all of which would define consciousness in terms of either the uh the behavior of uh uh a a an entire creature um or the behavior of its parts in interaction with one another. And in the latter case that might include um interesting things like implementing algorithms fans of computational theories of the mind uh uh are are interested in the idea that our neural states implement algorithms and that this has something to do with some aspects of what we traditionally consider uh the mind. And uh I I think it's uh it it's not that useful typically when someone says well okay this theory denies the existence of phenomenal consciousness but it doesn't deny the existence of consciousness because uh the subject of all of the controversies that have uh if anything only built over the last few decades are in are about phenomenal consciousness which um most people once they once they've grasped the idea it's just like how things feel from the inside as opposed to how the parts move about which is observable from the outside at least if you uh uh uh if you uh avail yourself of surgical methods or other imaging methods. Um once people grasp this idea it it seems a pretty clear to them that this exists in indeed um people tend to sympathize when they read Daycart's first two meditations and he suggests this is the thing we know better than anything else even if I'm dreaming even if the uh observable world is an illusion I do know I'm having these experiences now and then B that that this does seem to be conceptually distinct from any sophisticated behavior or function that can be fully understood in terms of the uh the movement of the uh different parts or the workings of the uh components making up our bodies.
¶24So that's that's the difference between phenomenal consciousness and functional consciousness. I actually think like functional consciousness in in many contexts is I if not uh uh merely unhelpful um a kind of uh a real misnomer because it tends to come down to being like responsive to one's environment in certain ways or being capable of processing certain environmental information in interesting ways. But these these are things that can be done by unambiguously unconscious uh things such as like an automatic door responds to its environment uh in a certain way. More complicated automter can do this and and it's misleading in the context of philosophy of mind without being really clear to to to refer to something like that when a human does it as consciousness. Well, but do we want to say that, you know, with a more robust definition of consciousness, a more common sensical notion?
¶25I I still don't think we want to say that all mental states are phenomenal conscious states. >> So, I wonder if there's a a broader category of the mental. >> Yeah. >> That doesn't just reduce to felt qualities. Like, for example, off the top of my head, >> you know, a belief is a mental state, but is a belief a a felt quality or a state of phenomenal conscious?
¶26No, but it's still a state of consciousness. I don't know. Maybe you can help me like untangle some of that. >> I think that's that's uh exactly right. Um consciousness at least uh you [clears throat] know in when we're in the context of debates about materialism versus dualism or pansychism etc.
¶27It it refers to this subjective phenomenology but but it it there are plenty of things that we think of in a broad sense as mental which do not necessarily involve or certainly don't seem to necessarily involve any such subjective phenomenology. So um noncurrent beliefs that you just have available to uh report on being asked all kinds of uh uh what what we think of as subconscious processing that goes on presumably in the nervous system. So that I don't know if you're working on a task and then you have a nap, you wake up being uh statistically likely to be a bit better at the task than if you uh hadn't had had a sleep like and I think it it's fine to call these uh mental um uh so long as we're being clear about our terms and and um for many of these processes they might be mental in a sense in which there is nothing particularly surprising about the idea that a computer could have mental states because by mental we just mean like engaging in a certain kind of sophisticated uh processing of information for example and and we could we could in another context use conscious like I don't think there's anything wrong with talking about a cartoon character on a a screen being conscious even though it's not really in that context it's obvious we're talking about it representing a conscious being and yeah maybe in other areas of cognitive science so long as we're being clear about our terminology uh function functional definitions of consciousness are actually going to be uh useful. >> Okay, that's helpful. Okay, so in our in our efforts to explore the conceptual terrain of the mental and consciousness, where do qualia fall?
¶28I have found on Substack that they are a very they're they're a lightning rod of controversy and I'm curious among professional philosophers of the mind. Well, first of all, if you tell us what qualia are, um, how controversial are they as as postulates, as things that really exist? >> So, I think I it's a great question. I I think that uh there there there has grown up a kind of um ambiguity about what people mean when they talk about qualia which has resulted in the term um being being perhaps not very useful. So, so when when I learned about qualia, I took this just to be a a a useful noun to refer to the subjective character of experience to refer to um phenomenal consciousness uh without without you know a terminology that's such a mouthful and that and that's it without without any theoretical commitments and in that sense like I I think um qualia are are something everyone who understands or more or less everyone who comes to understand the concept uh grants.
¶29They they really seem to exist. It's just the content of your your experience as you have it. However, there are others who have attached to the term more theoretical baggage. Um, and in particular, uh, Daniel Dennett tends to associate the term qualia with things like, um, I don't know, having having all of their properties intrinsically there's a there's a few other things and and he uses this as a way of then arguing maybe qualia don't exist and this can cause confusion because uh, you know, the thing which satisfies all of these theoretical um, criteria might not exist even though the thing that one uh understands um when one one uses qualia just to refer to subjective phenomenology might still exist. So I I remember when I started my PhD with Tim Crane, one of the first things I wrote used the term qualia and uh he he advised me maybe just don't use that term.
¶30Talk about phenomenal properties, talk about uh the phenomenal character of experience because qualia results in in these uh in people talking past one another. I think >> yes. So qualia as I take it too just refers to like the felt qualities of experience. So the standard examples would be like the redness of a red apple or >> the pain of a tooth ache or the the tastiness of a of a good meal like the the felt qualities. And on that reading, unless you're an illusionist, I guess you're going to affirm that qualia exist, even if you might not affirm this fuller package of metaphysical commitments that sometimes are attached to the label qualia.
¶31>> Yeah. Yeah. That that that's exactly how that that's how I would prefer to understand the term, but I now tend to avoid using it because I know uh one invites misunderstanding by using it in in that way. Although I like I suspect that was how it was typically used before before this confusion arrays. >> Okay.
¶32Okay. So that's helpful. That starts to give us that an understanding of what the mental refers to. It's often the the what it is like of experience that inner perspective looking at things from the inside. The these aren't like perfectly adequate but I think they serve to get you into an understanding of the term.
¶33One another controversy that's swimming around Substack is the apparent inability of defining physical. When I started to look into like methodological naturalism and science, one aspect of that was in thinking about Hemple's dilemma and trying to define what it means for something to be physical. And it's actually very difficult to do that. And sometimes depending on the context people will use that as a reason to reject physicalism as if we can't define what it means to be physical then the thesis that only physical things exist that's just unintelligible but I think troublingly um that is going to cut across the divide to basically every view that uses the term physical to define itself even if it's asserting that there are non-physical things. After all, if physical doesn't mean anything or we don't know what it means, then what does it mean to say that there's a non-physical or non-material soul?
¶34If you don't know what physical is, how do you know what non-physical is? So, so I don't think that it's best to see that as an argument against physicalism, it's threatening to render the whole mindbody problem unintelligible. So, first of all, what does it mean to be physical? And if we can't say that, if we can't give a concrete definition, does that really have these sweeping implications? >> Yeah.
¶35So, um I I think part part of uh the difficulty here uh is usefully understood against the history of philosophy. So, the position known as materialism has existed for 2,500 maybe 3,000 years. You get early proponents of it in uh ancient Greece, Democratus who's uh classed as a prestocratic although I think he's actually contemporary of Socrates. Uh and then you get the Charvaka school over in classical Indian philosophy. And broadly speaking, the um materialists right up until I guess the the the the French materialists of the uh uh 19th century Marx and others see their view is everything is material in the sense that it is made of matter understood as uh threedimensional chunks of stuff.
¶36stuff characterized by extension, solidity, locomotion, a kind of intuitive notion of uh material stuff. And they even had like arguments for thinking that's all that could exist. So Epicurus has this argument that says um uh what is immaterial has no extension. What is what has no extension doesn't exist anywhere. It doesn't have location.
¶37And what doesn't exist anywhere doesn't exist. Um now modern physicalism is very much the heir to that materialist tradition. However, the developments in physical science in particular in physics that we've seen over the last uh uh century and a bit have made it um harder and harder to stick to anything resembling that notion of matter. And so the solid matter of materialism was replaced with this idea of the physical as just like whatever physical science describes which might include the the spaceime of general relativity. It might include the uh wave phenomena of particle physics and so on which don't look like traditional democrat and chunks of stuff.
¶38But then there's this problem you refer to hemple's dilemma. Well, hang on. The stuff physical science describes, well, physical science um is a work in progress and we don't know what it might describe in the future. So, we could say physical means what is described by physical science as it is now. But in that case, physicalism looks likely to be uh importantly false because we'll probably discover new particles, new kinds of field.
¶39Maybe we'll reduce some of the existing stuff down to a simpler set of fundamentals in the future. On the other hand, we could say, well, physical means what physical science will describe in some ideal future once we're finished. But but then it's not clear we have much idea what might count as physical and what won't. We don't even know if there will be anything recognizable as physical science a thousand years from now. Maybe we'll see the current age as a highly naive pre-paradic phase in our journey to some unrecognizable new way of understanding the world rigorously and exhaustively.
¶40Now, I I do think like I've seen as you refer to some people use this as a a way of dismissing physicalism. And I think that's at least not obviously unreasonable if your view is that this whole debate isn't really getting at anything concrete. And indeed um [clears throat] my my my PhD supervisor I referred to Tim Crane uh he he co-authored a um one of the main articles pressing this point. On the other hand if you think uh intuitively no there there is actually a substantive debate over whether the mind or the conscious mind could be physical or not. then you're not going to want to to use the uh indeterminacy of the term physical a as a way of arguing against physicalism.
¶41So you'll need need some way of clarifying what is meant by physical that doesn't uh result in this problem. And I I actually think there are a few like satisfactory ways to do this for the purpose of getting on with the um substantive issues around the mind body problem. I I guess uh a popular and I think pretty good approach is to say okay well that let let's understand the physical as roughly speaking the stuff described by physical science now or in the future with the further proviso that it is fundamentally non-mental. So may you know physical science might develop a lot in the future new kinds of particles and fields maybe stuff we can't really you know new kinds of structures that we uh uh can't anticipate now but so long as what it is describing continues to be regarded as fundamentally non-mental so long as the particles fields forces do not themselves undergo uh subjective experience or anything like that then then it counts as physical um in a sufficiently strong sense to uh raise the question. Could our conscious minds somehow be nothing o over and above physical going on so defined?
¶42Does that threaten to uh make it difficult to understand what pansychism is asserting? I realize that's a spanner in the works. But pansychism would maintain that everything is fundamentally conscious. >> But does that mean that it it depends on who you ask about whether or not pansychism is a physicalist theory? But I think it challenges our intuitions here because it would just say that those things studied by science today are fundamentally conscious or you want to cash it out.
¶43>> Yeah, absolutely. So I I think it's it's exactly right that uh the this fairly popular definition of the physical that we can use in spelling out the problem of consciousness or the mind body problem more widely um has the consequence that pansychism is a view on which there is no such thing as physical stuff physical matter. um in that sense it doesn't exist. There's only this fundamentally uh mental uh phenomenal or some some would say protophenomenal stuff. Um and I think I I want to say like that's that's a perfectly acceptable consequence of this definition.
¶44It is true that a pans psychist like Philip Goff or Galen Strawson does not believe that there exists the kind of stuff that a physicist like David Papo or Daniel Dennett thinks uh the entire universe is is uh made out of. They think there is no such thing. Um however it is true that a a drawback of this definition of the physical um which is analogous to the case of the uh uh what if animals turned out to be furred and feathered robots um or what if demon possession turns out to be a psychiatric disorder that we discussed earlier. A drawback is well if it turns out that pansychism is true we we would still want to say well there is a sense in which you know the physical stuff is still all here it's still all around us it's just that it has a very different nature to uh the nature we thought it had in virtue of which it it might be reasonable to no longer call it physical or it might be reasonable to revise what we mean by physical having come to this conclusion and actually Galen Strawson is someone who I think in in his very good uh when was it 199 something book I think maybe maybe it was a little after that there he defines physical in such a way that pansychism entails there is nothing physical um and later on that that's a bit of simpl simplification but then later on he he moves to arguing no we we we should treat pattern psychism as the only viable form of physical physicalism um because that we don't need a term physical that refers to fundamentally non-mental stuff because there is no such stuff and uh he says I my my view is the real physicalist view the real materialist view I have to say I find that like I can see exactly why he says that and I think the papers in which he uh urges that view are some wonderful uh works of philosophical that there there beautiful to read as well as philosophically insightful and rigorous, but I think it's a slightly unhelpful move to make because it it ends up in more people talking across one another. >> Yes, I think that's the the worry.
¶45And why I guess my initial question was why doesn't that definition of the physical beg the question against certain reductive theories of the mind? Like don't these theories assert that mental states are physical states? And if that's the case, then we then something being fundamentally mental could still allow it to be physical conceptually. Do you see what I mean? >> I think this is a this is a an interesting point.
¶46So it's the the fairly widely used definition says the physical is what's described by science with the extra criterion that it's fundamentally nonmental. Now that that phrase fundamentally non-mental uh still needs spelling out more clearly. A common way of doing this is to to do so in terms of scale is just to say there is no mentality or or at least no phenomenal mentality no consciousness below a certain scale. Not at the scale of particles and fields. I I don't know.
¶47I mean fields they're not actually small scale but but the the building blocks uh do not involve mentality. It's okay if some of the aggregates formed of them do. I'm not I'm not actually like a massive fan of that approach. And um I think we can we can do something better in saying like uh I I if X is nothing over and above uh certain non-mental things then X counts as fundamentally non-mental even if X is itself mental. um that there's that it gets very complicated thinking about uh this precisely because you end up with lots of double negatives that you have to think through but I think there might be a slightly cleaner approach like that.
¶48Either way this this allows that there is there are minds that there are thoughts and experiences. The crucial thing is either that they are entirely made out of non-mental components or that they are nothing over and above non-mental uh entities. >> Yes. Okay. Because I wanted to say that like an identity theory according to which a certain mental state say a thought is identical with a certain brain state.
¶49>> Yeah. doesn't suddenly if true imply that the brain is non-physical because there's a a there's a mental state attached to the brain and science could study it. But what you're saying is fundamentality is like the relevant >> but that that brain state would be mental but it wouldn't be fundamentally mental because it would still you could disagregate it into electrochemical occurrences that that in involve no mentality in themselves. Okay. So zooming out to the highest level of generality.
¶50If we think the mind body problem is how does the mind relate to the body? How do mental states relate to physical states? Then how would you characterize like the main families of of options here? You have physicalism which would assert some sort of reducibility or perhaps even identity between the mental and the physical or the mind and the brain. You'd [clears throat] have non-physicalism, which could take a variety of spec specifications, and then of course there's pansychism, which is hard to figure out where that fits.
¶51Um, but what would you say is like the most helpful way to to approach the taxonomy of of answers to the mind body problem? So this is a question I' I've thought a lot about and um I I'm I'm a big fan of uh Christian Wolf's approach to this issue in a work called the German what we refer to as the German metaphysics um in the middle of the 18th century where where he puts in place this uh influential triotomy that we have to choose between of um physicalism, idealism M or dualism where physicalism says it's all physical. Idealism says actually it's all mental and dualism says no there exists both the mental and the physical and nei neither is um reducible to or nothing over and above the other. Um I think that's quite a good starting point. It it then then one has to draw draw some distinctions because you could be a an eliminativist physicalist who says it's all physical and there's no mentality.
¶52Or you could be a a softer physicalist who says it's all physical fundamentally but there are thoughts and experiences. It's just these are somehow nothing over and above fundamentally non-mental physical going on. And you get that same distinction on the idealist side. And then in the middle the dualists you've got two options. And uh some more complexity arises here.
¶53Christian Vulf, it's pretty clear he's thinking of what is now known as substance dualism where you have mental and physical substances. And a substance in this context uh is best understood as meaning something that can exist separately in in the way that um uh it it is possible for uh a page of this book to exist separately from the rest of the book. if I tore it out, which I would never do. But it's not possible for the shape of this book to exist separately from the rest of the book. You can't separate those two.
¶54That's because the shape is a property of the book, whereas the page is a substantial part of the book. Um, so if you think, oh no, mental and physical are both real and uh fundamental, you've then got a choice. Are you going to say there are mental and physical substances? So there are bodies and there are minds each of which can exist separately from the other. That view is apparently more or less the cognitive default for humanity globally and across time.
¶55Uh it looks like more or less every culture we know about at least exhibits the idea of uh non-physical minds or souls or spirits. mental entities, psychological entities that can exist separately from uh bodies. And um this usually comes up in beliefs about uh a disembodied afterlife, ancestral spirits, that kind of thing. But you'd also have the option of adopting the position that became popular in the 1990s among a lot of cutting edge philosophers known as property dualism which says well well in its standard version it says all of the substances are physical substances uh tables chairs brains bodies but some of them have fundamentally non-mental properties >> or mental properties >> sorry sorry quite right yeah that's right sorry fundamental mentally mental properties. That's right.
¶56Um so so my brain perhaps has the property of undergoing the experiences I'm now undergoing. But that's a property of the brain which couldn't exist separately from the brain. Um that's known as property dualism because there's two kinds of property only one kind of substance. Interestingly you could also do it the other way round. You don't see much of this but you might say all the substances are mental.
¶57uh all that exists are souls or spirits or lienitian monads, but some of these mental substances have fundamentally uh physical properties. Um that there's a way of reading um Thomas Aquinus according to which a human person could be understood as a fundamentally mental substance who has fundamentally physical properties. Um but but this that case aside isn't a view you get much. So property dualism tends to be of the former kind. So you got physicalism, idealism and then these two kinds of dualism.
¶58Then you have [clears throat] this uh question of well where does pans psychism fit and I think um some of the confusion over this arises because people want to see see it as like another view on the same uh uh dimension as these views. But actually I think this is intro introducing a second dimension uh to how we can distinguish between different views because the the core uh conceit or perhaps insight of the kind of pansychism that is seriously discussed in the contemporary literature is this idea that well maybe what we are thinking of uh as fundamentally non-mental physical stuff. Actually, maybe it is fundamentally mental. Maybe every atom in its extrinsic properties has the kind of prop, you know, uh structural and dynamic properties described by physics, but intrinsically its existence consists in a uh a faint glow of conscious experience of some kind. And well, well, that can sound like a crazy hypothesis.
¶59Um there are some theoretical reasons that have been recognized since well at least Arthur Edington and Burton Russell probably I would say since Linets and maybe before that for um thinking this this is quite a theoretically attractive idea in the way that it might help us to explain the contents of reality uh elegantly without positing lots of different kinds of things or having strange uh jumps in the nature of things. So that idea maybe maybe um the stuff described by physical science actually has a uh a deep nature that is mental. I think that's a move that can be made by um both dualists and monists. It's it's not it it's a move that that uh a proponent of uh uh in a sense any of the three options of physicalism, idealis, dualism and idealism can make although the physicalists and the idealists are are likely to end up uh converging if they do so. So just to illustrate this, you you could you could be um an idealist of a baron kind who says in some sense all all the physical stuff around us it its existence just consists in being perceived by us.
¶60So in some sense it doesn't really exist or it's it's non-fundamental. It's not out there. But you could be a an idealist of a liitian kind who says everything's fundamentally mental. But but that doesn't mean there is no such thing as the book outside of my mind and your mind and God's mind. There is.
¶61It's just it's made out of uh minds of its own. It's made out of atoms, each of which is a little mind or something along those lines. Um likewise, uh I if you're a dualist and you think that there are some fundamentally non-mental physical things, you might think there are some other fundamentally mental things described by physical science. Maybe you'd think the Furians are fundamentally mental mental but the Bosans aren't. So I I see uh I see Wolf's tricotomy as basically right physicalism, idealism, dualism.
¶62If we grant the the definition of the physical as um that which is described by physical science and fundamentally non-mental and then I see the pans psychist move of questioning that assumption as as uh leading [clears throat] us in a different along a different dimension of uh positions. >> Okay, good. That is very helpful. I have always struggled with the distinction between property dualism and substance dualism. I don't really know or get what it means to have a me an irreducibly mental property that is not itself an aspect of a mental substance.
¶63So I I go back and forth where sometimes I think I get it, I see it, and then it it's gone. Like why isn't property dualism just a form of physicalism? What does it mean to have a mental property of a physical thing? Yeah, I think this is a great question and um my my I my book the mind body problem metaphysics was motivated I precisely by that puzzlement you you express what exactly are we supposed to be picturing here when we're told that there are fundamentally non-mental phenomenal experiential properties that belong to a a brain bra or to a body. Um to use a metaphor of John Cells rather like the frosting on a cake.
¶64Uh say [snorts] uh the frosting on a cake example is actually I I mean it it it presses the problem because the frosting is not a a a mere property of the cake. It's actually a substantial part. You know that because you can take the frosting off. So So what what Well, go ahead. I was just going to say maybe another way to intuition pump the problem is like an equally challenging thing would be if somebody said that non-physical things can have physical properties.
¶65Like what is it even mean to say that there's a thing that is not itself physical but has the property of shape to it or weight or mass or any number. like it seems it's very conceptually difficult for me to detach the properties from the substantial stuff that they are properties of. Anyway, there you go. >> Yeah, I think it's I think it's it's difficult in that direction as well. Um there are some qualifications I'd add to that about definition of physical and so forth.
¶66on. I could uh uh uh get back into that stuff, but so here's here's one reason why I don't think there is a clear unambiguous answer to this in the literature on property journalism. the leading proponents of property journalism uh in characteristically deny the existence of non-physical substances or or at least uh uh express doubt about that idea. affirm that there are fundamentally uh non-physical mental properties but they do not define substance or property or indicate what the difference between the two is supposed to be. So uh part of my research and I have a very long paper about this in uh the review of metaphysics has been to to to try and work out what what ought these terms to mean in this context.
¶67I mean I think people people do have an intuitive grasp. Yeah. A non-physical substance is like a cartisian soul or a platonic soul. It's that kind of thing. Um but but what is the important difference between that kind of thing and a uh uh phenomenal property as conceived by someone like uh Charmer's Kim Jackson?
¶68Well, I think the best answer is that um a substance is something that can exist separately and a property is inseparable from the thing uh to which it belongs in the way I illustrated with the page and the shape of the book. So what the property jurist needs to say is that experiential property uh properties belong to the brain or to the body in the same way as say the shape or the uh weight of the brain belongs to the brain and can't exist separately from it. Um, now I think that's like at face value a uh it's not a self-contradictory position at least at face value. So there's something to uh argue about there. Interestingly though, well another thing property jurists don't tend to do is give any reason for preferring this form of dualism to substance dualism.
¶69Um they they tend to take it for granted. Substance dualism is is beyond the pale. It's crazy. Uh, so if we're going to be dualists at all, we should be property dualists. And furthermore, as you already indicated, um, it's not clear that it makes sense to say an experiential property belongs to a brain.
¶70It's not clear what we're supposed to picture. uh when we picture that one one way I've put this is is that the properties that belong to an object usually strike us as having this characteristic of interfusing with one another. So the shape of the book is is the shape of something of a certain size and the size of a book is the size of something of a certain shape. These these kind of uh lock together in a way we find comprehensible. If I then said, "Oh, yeah, and the book is undergoing severe pain." Uh, I can I can sort of say to myself, there is an experience of severe pain and point to the book [laughter] uh over there.
¶71But I'm not sure what it means to say it belongs to the book. Well, ultimately, and maybe we'll discuss this, I actually think like that that sense of puzzlement you expressed um is on the right track because the kinds of arguments that people give in favor of property dualism, I think um can also be used to show that if there are non-physical phenomenal properties, they do not belong to fundamentally non-mental physical objects. that is actually an ultimately um if not incoherent view at least one that is ruled out by the very motivations that are usually brought to bear in its favor. So, we've been focusing on the minutiae of terminological clarifications, which honestly I love, but I think people would be upset if I didn't ask you um about a something a bit more substantive, which is, you know, why should we be physicalists? Why should we not be physicalists?
¶72Is there some good reason to be a dualist of one sort or another? And so, I know we started to get to this uh question of whether substance dualism was a better position than property dualism, but what's wrong with physicalism? Like if you had to give us the one key consideration that is in your mind the most powerful factor weighing against physicalism, what would that be? So uh I mean I' I'd love to talk also about why what reasons can be given in favor of physicalism. As for the reasons against physicalism, uh it it seems to me that um the physicalism is conceptually incoherent um unless we give up on the existence of phenomenal consciousness.
¶73And although I think there are uh really ingenious uh attempts to reconcile um us to to abandoning phenomenal consciousness, some of some of which some of the most ingenious even allow us to still still affirm that phenomenal consciousness exists, but using those terms in what I would describe as a revisionary way. Um, I just don't I I don't think any of these attempts um makes any headway in dispelling my sense that they are denying something profoundly more obvious than any of the um arguments given in in favor of physicalism uh are likely ever to be. So, uh, I I'm I'm kind of a fan of, uh, you'll know about the the the various conceivability arguments against physicalism. And, um, something I've been thinking about a lot recently is uh, whether it's possible to improve upon these arguments to make them even even more robust. Um, and and and I have some thoughts about that.
¶74I I should say like pe people who haven't thought about this subject before I find from my students tend to find the conceivability arguments totally baffling at first. They don't find them immediately intuitive. Um so I don't know if they're the best way into seeing what's wrong with physicalism. The basic concern is it it seems pretty clear that no description no description of the physical world in terms of its physical parts, properties and dynamics however detailed is ever going to be such that we are able to see ah yeah um any such physical going on would have to uh result in include comprise some subjective phenomenology of a certain kind. Liveven expressed this back in the 17th century um where he uh suggests we we we imagine uh the uh brain or body being uh blown up really big so that we could enter it and look around it like walking into a mill.
¶75And he says, well, what we would see is various parts pressing against one another, moving around, complex mechanics, but we wouldn't find uh in his terminology any perception there. We wouldn't find any conscious experience. That's an idea that's also expressed well by Frank Jackson in the Mary argument. Uh suppose uh Mary is a scientist who knows everything physical science can tell us about color perception, color vision, but she's never experienced color herself cuz she's been trapped in a black and white room. Uh well, when she goes outside, she seems to learn something new.
¶76She seems to learn what colors look like, what it is like to see blue, to see yellow, which she couldn't have learned just from the physical science. So all of these are different ways of saying there seems to be a conceptual gap between the physical and the phenomenal. Um perhaps the most uh blunt way of putting it is in terms of philosophical zombies. A zombie is defined here not as a a being that goes around eating brains. A zombie is a physical duplicate, an exact physical duplicate of an actual human being except that it's all dark on the inside.
¶77So the zombie, it still looks both ways before crossing the road, but it doesn't undergo any visual experience. It does presumably process the light coming in and uh you you know use that enter it into some algorithm for deciding when to walk. The zombie will scream if you uh pinch it, but it won't undergo any feeling. It won't undergo any experience. And uh a contention that's widely agreed upon even by physicalists is that there is no logical contradiction in the idea of a philosophical zombie in the idea of a uh atom for atom duplicate of a human being that moves around in exactly the same ways but it's all dark on the inside.
¶78In other words, there's no some as some people would put it, this is conceivable. uh we can't rule it out just by thinking about it. Now, uh, probably the most popular argument against physicalism is the argument that says, well, if zombies zombies are conceivable, if zombies are conceivable, then they are metaphysically possible where this means although uh they presumably don't exist, never will exist, it would be crazy to suppose they did. Nonetheless, this is something that could exist in a uh the most general sense of could. There would be nothing stopping an all powerful being like God from creating a philosophical zombie.
¶79And if he did so when he wanted to make it conscious, he would have something further to do. Therefore, consciousness is something non-physical. It's something extra, something over and above the physical. I I think that's a I think that's a ultimately a completely sound argument. Although there are places where people push back um what what exactly is the relationship between conceivability and possibility?
¶80Maybe this is only conceivable and not possible. That kind of thing, which is something I've been thinking about uh lately. [clears throat] >> So, this will get into the weeds a bit, but that's okay. When it comes to philosophical zombies, I think that I'm I've always been innately skeptical that we have this ability to access the metaphysical possibilities of these kind of extravagant cases. I think I'm >> I'm attracted to a a moderate form of modal skepticism >> of our ability to know what's possible and impossible because I think that and and Peter Vaninwagen comes to mind.
¶81I came across his proposals about this sort of thing when he's talking about the problem of evil and like what it would take to show that there really are possible or that there are no possible reasons for permitting this evil or that evil. Anyway, um and what he says is that we have to be able to for the conceivability of X to count towards its metaphysical possibility, we've got to be able to picture or conceive of X at a sufficient level of granularity. And so when it comes to like the brain and whether or not I can conceive of a philosophical zombie, I just don't know that I'm capable of conceiving it in my mind's eye to a level of detail required to then say, "Okay, I really am conceiving of a philosophical zombie rather than just kind of like a blurry approximation thereof, and I can see that that shows that they're possible." I don't know. I mean, maybe maybe I'm too skeptical in that regard, but I wonder like how much detail [clears throat] do you got to put into your >> your mental conception of a thing in order to see that okay, it's really possible. >> Yeah, this is really interesting.
¶82In fact, I think you maybe raise two separate issues there. One is whether our conceptions need to be more granular than they uh are. And the other is whether in engaging in conceiving of this kind we get any access to metaphysical possibilities which you know sound pretty mysterious whatever whatever those are. Um so on the granularity problem I see I I think a a fairly standard response to this says yeah um we [clears throat] might be missing something when we try to conceive of the uh zombie um we should uh be open to that possibility and the fact that we can't discern any contradiction in the idea of a atom for atom duplicate of a human that underos no conscious experience um is only evidence that there is in fact no contradiction, no incoherence in that idea. However, um we can still make the argument and the argument will have whatever strength uh we attribute to the evidence for the lack of any contradiction in this idea.
¶83And I have to say personally I I think uh it certainly seems to me that this is a case in which um well there is people sometimes distinguish positive and negative conceivability where positive is like forming a a fully integrated picture of it in your mind and negative is not being able to rule it out uh just by thinking just by discovering a contradiction. So, so certainly we can't fully positively uh conceive of a zombie in all of its detail. On the other hand, I'm I'm pretty confident that we can see that it is we have really good reason to think that it it truly is negatively conceivable uh in a in such a way that we're not missing some contradiction which which could be found by someone with a more powerful mind than ours or by future scientific inquiry. So I think that gets I think that gets around that point. Although there are there are some people out there who are like holding out for for the logical proof that certain physical structures just have to uh feel like something for the in from the inside.
¶84I think and that that would definitely satisfy me if we could if we could find one uh uh that that would that would be a wonderful discovery and make physicalism a very attractive position. The other the other thing you raised there though so is is whether we are accessing metaphysical possibilities here. Um it it depends. I mean you said you're a modal skeptic of a of a kind. Um, one thing I want to add about this argument is that I don't think it relies on any ability to discern metaphysical possibility beyond what is presupposed in ordinary mastery of language in ordinary totally everyday linguistic understanding.
¶85And um there are a couple of ways of thinking about this. One one is that on a um [clears throat] fairly standard way of understanding how words work. Um part of the meaning of a term is its so-called intention. Uh intention spelled with an s. uh where an intention can be understood as the function that takes you from some possible scenario to the reference of that term in the scenario if it's a referring term or to the truth value of that term of that scenario if it is a uh proposition or an assertion a sentence.
¶86Um so for example uh if I tell you a story I say once upon a time there was a uklidian plane and on that ukidian plane there was a closed three-sided shape maybe I fill in some further details then I could then I could ask you are there are there any triangles in that story? uh whi which entity in that story was the triangle. To understand the description uh that that delivered the story and the word triangle is to be in a position to answer correctly about whether the intention of the word triangle is satisfied by anything in the story. someone who claimed to totally understand the story but said there were no triangles there uh we would clearly be misunderstanding something. Um now if if one accepts that picture of um how part of the meaning of language works there's much much more to be said about how language works but this is part of what's going on on on a very standard view.
¶87Well, there seems to be a trivial sense in which um to fail to see that some scenario that has been described, say the zombie scenario satisfies the intention of a term, say um uh Ralph is experiencing visual phenomenology um to fail to see that just just is to have failed to understand the meaning of one or more of the terms involved. It's just trivally true to understand the meanings of terms is to be able to recognize when their intentions are satisfied um and when they are not and by what. I actually think this is getting into the weeds a bit. I actually think you can you can do all this without even mentioning metaphysically possible world. But I think all we need to describe are all we need to talk about are descriptor uh scenarios that have been described and descriptions that have been understood or not understood.
¶88So I I I'm more more and more confident in the radical view that UT place seemed to have buried in 1956 according to which um physicalism is actually just semantically incoherent. Be that as it as it may, yeah, I don't think you need anything more than a a a trivial, extremely innocent kind of uh access to uh what is possible and what isn't for the argument to have its full force. for it to be the case that um if there's no contradiction in the zombie scenario in a atom for atom duplicate of a real human being having no conscious experience um well it it and we have not misunderstood the terms we're using then it it follows that uh it is not true that something that is physically exactly like the zombie and nothing more exists is conscious. That would just be a misuse of the word conscious. Um so a physicist is going to have to say it would seem to me that we have misunderstood either the uh phenomenal terminology or the physical terminology.
¶89We must have misunderstood some some of these terms in making the error of thinking that the zombie scenario involves no contradiction. >> Yes. and and in fact that is what physicists generally say either implicitly or explicitly. >> Okay. Okay.
¶90Well, let me shift gears slightly and ask you about a related set of issues. Uh Philip Goff very recently said something like physicalism, idealism, pansychism, dualism. These are philosophical thesis, philosophical views. >> And [clears throat] as such, science cannot adjudicate between them. All of these theories, you might say, have identical empirical consequences.
¶91And if we are to assess them, we need the tools of the philosopher rather than the scientist. It would be kind of like asking science to demonstrate to us that that murder is wrong. It's just kind of a category error. These facts are not amendable to scientific investigation. So do you agree with that empirical equivalence thesis even in principle that that science cannot adjudicate between these different philosophical views?
¶92>> Yeah, what a good question. Um I've heard Philillip say that as as well. Um and he certain about it. There might be some I think there's a truth a truth in the area but I don't know about that. Anyway, go ahead.
¶93Yeah, I I would I mean I agree with Philip on a lot of things and we've actually we've just co-authored a a chapter for a new book on uh metaphysics um where we where we talk about some of the things we we agree on about this. This is a case in which I would I would qualify what he says here. Here's what I think is true. There are empirically equivalent versions of physicalism, dualism, idealism, uh including both pansyist and non-pansy versions of these views. And so it is true that once all the physical science is in um no matter what it says, it's going to it seems to me it's correct that it's going to remain a further philosophical question which of these positions we adopt.
¶94I mean maybe I'd like say like okay who knows maybe we'll make some incredible unimaginable advance in physical science which would change my mind on that and made me think but but I I I think we have very good reason to think think that uh nothing physical science could tell us could rule out all non-physicalist theories. Um, however, I would add that the most plausible and attractive non-physicalist theories are in fact ones that physical science could in principle challenge um and perhaps even rule out. And my reason for thinking that is that uh it seems to me that uh we have overwhelming uh empirical uh in the deepest sense of a term grounds to think that subjective experience exists. And I I would say this with other kinds of mental state too, but subjective experience is perhaps the the plainest. And we have pretty uh overwhelming grounds for thinking that it is um causally efficacious in the physical world.
¶95So that like uh I I always use the example of like my desire to sip from the glass of water there causes me causes my physical body to to reach out and grab the water which is a a movement in the physical world. There are many other examples voluntary actions, involuntary actions, screaming in response to pain perhaps if that's not a reflex and so on. Now, furthermore, uh it I I think it is correct that it would be a bizarre coincidence if um the conscious mind were real, were something over and above the physical world. And yet the physical effects produced by it were always effects that were already going to happen because of the physical causes in the vicinity. So it it would be really weird if uh actually yeah I do have say a carteesian soul or a platonic soul and its desire for water does cause you know can can push certain neurons in my brain to uh initiate the uh action of my reaching my arm out.
¶96But whenever it does so, the the the relevant neurons were already about to be stimulated in the requisite way by prior neural activity or prior envir environmental factors, etc. That just seems that seems mad. Um, and actually I think like I I've got a paper no one reads because uh uh I I it it because its title is a bit misleading and uh uh I guess it's in a book not a journal but about whether idealism solves the problem of consciousness where I go into this in some detail and explain why I think uh on ordinary standards of theory choice we would never um uh posit causal relations of that sort. So this is what's known as causal overdetermination. The idea here is that it would be crazy if my reaching for the glass and all of the other things I do in response to my mind are causally overdetermined in the sense that they are brought about simultaneously by independent physical and mental causes just by coincidence.
¶97Now, if all that's right, that's a bit complex, but the point is if all of that is right, then on the most attractive versions, non-physicist theories, it's going to be the case that physical events that are caused by my conscious experiences, including perhaps my conscious thought, valitions, etc. are going to be events that we would not expect given just the physical causes in the vicinity. That there would be causal anomalies in the nervous systems of animate entities of human beings, other mammals, who knows maybe all the way down to fish and insects depending on uh where your judgments about the uh science of sentience take you. And if so, that would be something that that physical science could in principle challenge. Uh indeed, there is a widely circulated uh uh view, a fairly popular opinion, though I think it is uh actually mistaken.
¶98according to which physical science has given us very strong evidence that there are no such causal anomalies in the nervous systems of animate beings of the kind that would be predicted on the most attractive non-physicalist views. Now, if that were the case, um I think that would be good evidence against the most attractive non-physicalist views. And although it would still we remain uh open to us to adopt uh uh alternative non-physical views um in or to to favor those instead of physicalism. The reasons for doing so I do think would would would be reduced. >> Okay.
¶99So I you lost me a bit on why the most attractive forms of non-physicalism would suggest anomalies. What what was the idea? Why does it have the implication? >> Yeah. Yeah.
¶100Um the the the the core idea is like it's really intuitive that the conscious mind has physical effects in the world. >> Um if those physical effects were always effects that were going to happen anyway given the physical causes present that would look like a weird coincidence. >> Yes. Therefore, it's uh uh more more attractive to suppose that they would be different effects and therefore that there would be causal anomalies in the physical world. Um is that like walk me through an I guess could you walk me through a specific like toy example of what that might be or what you mean?
¶101>> Yeah, I mean I guess um I I wonder whether it's best to use an example of a voluntary action or not because um free will brings in further sets of intuitions. But um it it might well seem to me like uh I saw that the sun's just come out. It stopped raining and uh that phenomenal experience >> Oh, wait. Okay. >> led me to to to make the decision, oh, I'll um go to the shop now because uh there there's an opportunity.
¶102it stopped raining. Now, if if uh it were the case that actually the um physical forces operating in my body were already completely sufficient for me to respond in that way to the physical effects of the light on my retina and so forth without the need for any conscious experience or conscious decision-m to go along to to occur that it would have happened anyway even if I'd been a zombie. Um it it the the conscious mind looks I mean one might say it looks like it's not really having any causal effect at all. Um and if it is having an effect it's this weird kind that always hides itself behind physical effects that were going to happen anyway that looks really implausible. Okay.
¶103So I think I get it now that on a view which takes the mind seriously and doesn't just have it along as like the proverbial fifth wheel that's not really doing anything. >> Yeah. from the view of the physical purely of your bodily inputs, bodily outputs, your brain states, for example. Like if you could monitor the brain on an MRI during a voluntary action, these forms of physicalism that allow for the mind to have robust causation will predict, however subtle, a gap in the physical causes >> pertaining to some situation. Like I see a picture of my favorite beer and suddenly I feel like craving a beer.
¶104I hate beer. I don't know why I use that example, but you see where the two things that are being causally related here or that are are involved, the picture of the beer and the the the uh state that puts your brain into and then the feeling of um desiring to get it or the choice to go get one perhaps. >> Those are physical phenomena. But if it's the the mental events themselves, the phenomenal consciousness that's playing a causal role, then if you disregard that and take purely the physical view, there has to be a causal gap. >> Yeah, I think that's that's a great way of explaining it.
¶105Um and and it would be it may be worth adding like it it would be an anomaly. Um I I if one were expecting to see only what the uh physical forces operating would bring about on their own, it wouldn't be anomalous um I in in a another sense because it would be the kind of thing that is going on all the time with considerable degree of regularity and >> uh you know on a view where there is um non-physical uh phenomenal consciousness that does indeed act on the physical world in the experiences intuitively do. Someone who had all the facts would see this going on all the time and think this is perfectly ordinary uh part of the way the world works. >> Okay. So you've convinced me about that prediction of the most plausible forms of say substance dualism or or other non-physicalist views.
¶106But then the question is we don't observe them. Maybe we don't observe their absence. Right? Like I I would think that the counter reply to that point that we haven't empirically detected these gaps is well they're very small and subtle and so they're beyond our observational capacities at present. But to me that that strikes me as a very ad hoc like let's get out of disisconfirmation by just kind of saying they're just too small at present to see.
¶107Um maybe not. Maybe it's a well motivated stipulation, but does our absence or the the lack of detection of these anomalies, does that give us some reason then to reject these plaus these these anticedently plausible forms of non-physicalism? >> Yeah, there it's a great question. I I think um it's definitely true that if we had no um independent grounds to think that there exists non-physical conscious experiences that are causally e efficacious then it would be crazy to posit them uh merely because we don't have evidence against them. I mean that that would be you don't posit something ju just because of an absence of of uh evidence against them.
¶108However, if we do have independent grounds for thinking that there are conscious minds that act on the physical world, um then uh the fact whether or not um the fact that we haven't observed this in looking at the workings of the nervous system uh counts against that view is going to depend on whether we think we would have observed these uh gaps, causal gaps as you call them. Um how were they present? And um this is a really interesting question. Um my opinion is well I there are a couple of things I think about this. One thing I think is that um the the grounds for thinking we would have observed such gaps sufficient to give the absence of these observations substantive evidential force have yet to be set out um in the literature on this.
¶109the defenses of physicalism. I I'm I'm not aware of anyone even attempting to sort of quantify like like how likely is it uh this would show up on fMRI, how likely is it would it would show up under two photon calcium imaging. People just just haven't yet done that work and I think it'd be very useful to do it. But one thing I think we know with a great deal we can we we can believe we can conclude with a great deal of confidence is that um it was not um it is not the case that physicalism became the dominant view in philosophy around the middle of the 20th century because we had at that time made observations which would be likely to show up these causal gaps if they were present. So we know we know um with a great deal of confidence I think that um if physicalists have gotten it right um then this they've they've done so by good luck by coincidence ironically by a kind of overdetermination.
¶110Um so uh and and this is where I depart from. So David Papo is one one of the leading physicists uh in the contemporary literature and someone whose work I admire a great deal. uh one one respect in which I disagree with him, however, is that he has a very influential paper in which he um defends the hypothesis that physicalism became prominent in the middle of the 20th century because it was at that time that we acquired clear-cut biological evidence for um the completeness of physics. meaning for the view that every physical effect is brought about by a series of sufficient physical causes with no gaps. And um there's some some things about that paper I really like.
¶111Uh he discusses why physics isn't enough to show this uh although it narrows down the amount of forces that people uh thought might be operating. Um but when it comes to the biology uh he doesn't go into the details. He only mentions um in a very brief overview we mapped the nervous system and measured the electrical activity of neurons and it just seemed like well there there are no non-physical forces operating. Now I have a lot to say about this but but my the the the core of my opinion is that the kind of evidence you need would have to be live brain imaging. an anatomical studies of dead brains isn't going to um show up the causal gaps even if they exist o obviously because we don't think conscious minds are active there.
¶112Likewise uh in vitro studies of isolated cells um uh uh the kind of study uh Huxley and Hodkin uh famously conducted in producing a model of uh the electrical behavior of neurons isn't going to uh um show up the gaps if they exist because we don't think the isolated we presume the isolated cell isn't being acted on by a conscious mind. It's going to have to be live brain imaging. And in the uh 1950s and60s, the period in which Papo uh identifies as like the period in which physicalism became the standardly accepted view. Our best brain imaging technology was electrophilography which um at this period consisted in about 20 electrodes being placed on the scalp. Uh and then uh these would uh uh they you you'd have uh eight or 16 channels that measure the voltage difference between pairs of electrons.
¶113So you might measure the difference between them and a an electron on the earlobe as a kind of comparison case. And then this would be uh these voltages would be used to control um uh ink pens which would then draw wavy lines on a reel of paper uh moving underneath them. So an EEG would give you eight or 16 wavy lines. Um and uh each of those lines would would represent a voltage difference taken from or influenced by millions of uh neurons over a very uh illdefined region of the brain. Uh neurons near the scalp obviously having uh the lion share of the effect.
¶114And um on a standard setting even a one millimeter displacement of the of the wave would require the activity the syn synchronous postsaptic activity of of probably hundreds of thousands of neurons. Now this is a really amazing technology. You could use it to do cool things. So if you see a sharp spike and then a a kind of long rounded wave uh this would suggest a a form of um epilepsy absence epilepsy. other other patterns suggest the patient's fallen asleep, but this definitely isn't the kind of thing that you would expect to pick up causal gaps in the uh physical uh or dynamics of the brain.
¶115And I think that's, you know, for for for a couple of reasons. First of all, this is just just leaving out massive amounts of what's going on, massive amounts of the causal ancestry of the activity that is causing the uh lines to do what they do. Uh secondly, e even what is recorded is non-deterministic. You can't predict with a high degree of confidence the second half of an EEG from the first first half. um all sorts of reasons.
¶116I don't think anyone would I've never seen anyone argue that EEG or any other brain imaging technology from this period would be the kind of thing that would be able to pick up even massive causal anomalies in in the brain. Even if you do see a massive anomaly on an EEG, you still don't know whether it has an ordinary physical cause like uh someone's uh uh having a seizure or or an explosive being planted in their brain or or whether it's a non-physical cause like uh uh they're being attacked by a a demon or a fairy, right? The EEG just can't tell you that. So I I don't I I think we can say with a lot of confidence that the popularity of physicalism is not due to good evidence um good negative evidence against causal an anomalies in the brain. But I think there's like really serious work that has not been done yet in thinking about what kind of anomaly would be more likely on the most plausible uh interactionist view and do we have any prospect of uh testing for this?
¶117Should we have observed it with our much much much more refined um modern methods of imaging? My my hunch is the answer is going to be there will be plausible versions of interactionism on which the uh uh uh effects are small. In fact, I think it's a general fact of of of the natural world that uh you you tend to have the um the the the least causal activity needed to bring about a given effect. Um and the brain is very very sensitive. It can amplify small influences to a large scale.
¶118So, it'll be plausible that it's quite small. And I think that it's also pretty pretty likely that even our very best imaging methods are going to leave out far too much given that like even two photon calcium imaging it it's it's often blurring different neurons. Uh it can't distinguish between um uh uh different firings when they happen in rapid succession as as happens a lot. and and it's it's not even getting us anywhere near the mechanics of the interior of neurons which is vastly complex in itself. Um so I I I think like there there is a really interesting interface between the the philosophy and the science here.
¶119Um but I suspect we will not get the kind of physical data we would like to be able to settle even this issue though though it is at least in principle thinkable that we could. >> Well in my last question for you I'm going to return to an older tradition of the channel which I have not kept running at all but it's not a gotcha question so no worries there. With respect to your philosophical views, >> of which of them are you most uncertain? Given that the name of the podcast is the uncertainty podcast, it's a it's a fitting way to end. I'm going to I'm going to bring it back.
¶120I'm going to I'm bring >> That's That's great. I I love that bit. I I was wondering if you were going to ask that because I' I've heard you do so on other podcasts, which is a pity because it's better if someone's someone's caught totally off guard. I mean, >> I know. I know because then they go, "Well, I have never thought about that." [laughter] >> Yeah.
¶121Yeah. I don't I don't admit to uncertainty about anything. >> Oh, they're all known. >> I I'm I'm I'm uncertain about almost all of these things. I I give uh uh two that come to mind are I'm very uncertain about why physicalism did rise to prominence.
¶122This is something I'm thinking about a lot at the moment. I have a hypothesis I'm thinking through which is um that it it's it's really a cultural reaction against the rampant spiritualism of the late 19th and early 20th century um both religious spiritualism parsychology related phenomena especially in the angophone world which I think might might be might be a better explanation chronologically geographically maybe also sociologically than than the um competing explanation Papo gives. I I I guess uh the other thing I'm really uncertain of is uh whether any of the arguments I find very compelling whether that is because I'm missing something. Uh >> so like this second order uncertainty. >> Yeah, that's that's that's right.
¶123That's right. Uh and and the one one disconcerting thing about doing philosophy over a long period of time is is you you have the experience repeatedly of thinking something is obvious. >> Yes. >> And then realizing that it's in fact false. I mean you get Yes.
¶124>> study other areas you you'll have that experience too. So uh yeah I I I feel haunted by uncertainty about that. Well, you and me both. I I relate to that real hardcore. [laughter] That's that's my whole life.
¶125Um well, Ralph, thank you for coming on the podcast today. Like I said, I've anticipated this discussion for a long time, and I think this was fascinating. I don't know much about the philosophy of mind. It's not my area of specialization, but I appreciate you taking the time to just be here and answer all my questions because I'm curious about this stuff. >> Really glad to do it.
¶126It's been great fun. Thanks so much for having me. >> [music]