First off, would you agree with my model of your beliefs? Would you consider it an accurate description?
Also, let me make clear that I don’t believe in cartesian souls. I, like you, lean towards physicalism, I just don’t commit to the explanation of consciousness based on the idea of the brain as a **classical** electronic circuit. I don’t fully dismiss it either, but I think it is worse on philosophical grounds than assuming that there is some (potentially minor) quantum effect going on inside the brain that is an integral part of the explanation for our conscious experience. However, even this doesn’t feel fully satisfying to me and this is why I say that I am agnostic. When responding to my points, you can assume that I am a physicalist, in the sense that I believe consciousness can probably be described using physical laws, with the added belief that these laws **may** not be fully understandable by humans. I mean this in the same way that a cat for example would not be able to understand the mechanism giving rise to consciousness, even if that mechanism turned out to be based on the laws of classical physics (for example if you can just explain consciousness as software running on classical hardware).
To expand upon my model of your beliefs, it seems to me that what you do is that you first reject cartesian souls and other such things on philosophical grounds and you thus favour physicalism. I agree on this. However I dont see why you are immediately assuming that physicalism means that your consciousness must be a result of classical computation. It could be the result of quantum computation. It could be something even subtler in some deeper theory of physics. At this point you may say that a quantum explanation may be more “unlikely” than a classical one, but I think that we both can agree that the “absurdity distance” between the two is much smaller than say a classical explanation and a soul-based one, and thus we now have to weigh the two much options much more carefully since we cannot dismiss one in favour of the other as easily. What I would like to argue is that a quantum-based consciousness is philosophically “nicer” than a classical one. Such an explanation does not violate physicalism, while at the same time rendering a lot of points of your post invalid.
Let’s start by examining the copier argument again but now with the assumption that conscious experience is the result of quantum effects in the brain and see where it takes us. In this case, to fully copy a consciousness from one place to another you would have to copy an unknown quantum state. This is physically impossible even in theory, based on the no-cloning theorem. Thus the “best” copier that you can have is the copier from my previous comment, which just copies the classical connectivity of the brain and all the current and voltages etc, but which now fails to copy the part that is integral to **your** first person experience. So what would be your first person experience if you were to enter the room? You would just go in, hear the scanner work, get out. You can do this again and again and again and always find yourself experiencing getting out of the same initial room. At the same time the copier does create copies of you, but they are new “entities” that share the same appearance as you and which would approximate to some (probably high) degree your external behaviour. These copies may or may not have their own first person experience (and we can debate this further) but this does not matter for our argument. Even if they have a first person experience, it would be essentially the same as the copier just creating entirely new people while leaving your first person experience unchanged. In this way, you can step into the room with zero expectation that you may walk out of a room on the other side of the copier, in the same way that you dont expect to suddenly find yourself in some random stranger’s body while going about your daily routine. Even better, this belief is nicely consistent with physicalism, while still not violating our intuitions that we have private and uncopiable subjective experiences. It also doesn’t force us to believe that a bunch of water pipes or gears functioning as a classical computer can ever have our own first person experience. Going even further, unknown quantum states may not be copyable but they are transferable (see quantum teleportation etc), meaning that while you cannot make a copier you can make a transporter, but you always have to be at only one place at each instant.
Let me emphasize again that I am not arguing **for** quantum consciousness as a solution. I am using it as an example that a “philosophically nicer” physicalist option exists compared to what I assume you are arguing for. From this perspective, I don’t see why you are so certain about the things you write in your post. In particular, you make a lot of arguments based on the properties of “physics”, which in reality are properties of classical physics together with your assumption that consciousness must be classical. When I said that I find issue with the fact that you start from an unstated assumption, I didnt expect you to argue against cartesian dualism. I expected you to start from physicalism and then motivate why you chose to only consider classical physics. Otherwise, the argumentation in your post seems lacking, even if I start from the physicalist position. To give one example of this:
You say that “there isn’t an XML tag in the brain saying `this is a new brain, not the original`” . By this I assume you mean that the physical state of the brain is fungible, it is copyable, there is nothing to serve as a label. But this is not a feature of physics in general. An unknown quantum state cannot be copied, it is not fungible. My model of what you mean: “(I assume that) first person experience can be fully attributed to some structure of the brain as a classical computer. It can be fully described by specifying the connectivity of the neurons and the magnitudes of the currents and voltages between each point. Since (I assume) consciousness physically manifests as a classical pattern and since classical patterns can be copied, then by definition there can be many copies of “the same” consciousness”. Thus, what you write about XML tags is not an argument for your position—it is not imposed to you by physics to consider a fungible substrate for consciousness - it is just a manifestation of your assumption. It’s cyclical. A lot of your arguments which invoke “physics” are like that.
Why would the laws of physics conspire to vindicate a random human intuition that arose for unrelated reasons?
We do agree that the intuition arose for unrelated reasons, right? There’s nothing in our evolutionary history, and no empirical observation, that causally connects the mechanism you’re positing and the widespread human hunch “you can’t copy me”.
If the intuition is right, we agree that it’s only right by coincidence. So why are we desperately searching for ways to try to make the intuition right?
It also doesn’t force us to believe that a bunch of water pipes or gears functioning as a classical computer can ever have our own first person experience.
Why is this an advantage of a theory? Are you under the misapprehension that “hypothesis H allows humans to hold on to assumption A” is a Bayesian update in favor of H even when we already know that humans had no reason to believe A? This is another case where your theory seems to require that we only be coincidentally correct about A (“sufficiently complex arrangements of water pipes can’t ever be conscious”), if we’re correct about A at all.
One way to rescue this argument is by adding in an anthropic claim, like: “If water pipes could be conscious, then nearly all conscious minds would be instantiated in random dust clouds and the like, not in biological brains. So given that we’re not Boltzmann brains briefly coalescing from space dust, we should update that giant clouds of space dust can’t be conscious.”
But is this argument actually correct? There’s an awful lot of complex machinery in a human brain. (And the same anthropic argument seems to suggest that some of the human-specific machinery is essential, else we’d expect to be some far-more-numerous observer, like an insect.) Is it actually that common for a random brew of space dust to coalesce into exactly the right shape, even briefly?
You’re missing the bigger picture and pattern-matching in the wrong direction. I am not saying the above because I have a need to preserve my “soul” due to misguided intuitions. On the contrary, the reason for my disagreement is that I believe you are not staring into the abyss of physicalism hard enough. When I said I’m agnostic in my previous comment, I said it because physics and empiricism lead me to consider reality as more “unfamiliar” than you do (assuming that my model of your beliefs is accurate). From my perspective, your post and your conclusions are written with an unwarranted degree of certainty, because imo your conception of physics and physicalism is too limited. Your post makes it seem like your conclusions are obvious because “physics” makes them the only option, but they are actually a product of implicit and unacknowledged philosophical assumptions, which (imo) you inherited from intuitions based on classical physics. By this I mean the following:
It seems to me that when you think about physics, you are modeling reality (I intentionally avoid the word “universe” because it evokes specific mental imagery) as a “scene” with “things” in it. You mentally take the vantage point of a disembodied “observer/narrator/third person” observing the “things” (atoms, radiation etc) moving, interacting according to specific rules and coming together to create forms. However, you have to keep in mind that this conception of reality as a classical “scene” that is “out there” is first and foremost a model, one that is formed from your experiences obtained by interacting specifically with classical objects (biliard balls, chairs, water waves etc). You can extrapolate from this model and say that reality truly is like that, but the map is not the territory, so you at least have to keep track of this philosophical assumption. And it is an assumption, because “physics” doesn’t force you to conclude such a thing. Seen through a cautious, empirical lens, physics is a set of rules that allows you to predict experiences. This set of rules is produced exclusively by distilling and extrapolating from first-person experiences. It could be (and it probably is) the case that reality is ontologically far weirder than we can conceive, but that it still leads to the observed first-person experiences. In this case, physics works fine to predict said experiences, and it also works as an approximation of reality, but this doesn’t automatically mean that our (merely human) conceptual models are reality. So, if we want to be epistemically careful, we shouldn’t think “An apple is falling” but instead “I am having the experience of seeing an apple fall”, and we can add extra philosophical assumptions afterwards. This may seem like I am philosophizing too much and being too strict, but it is extremely important to properly acknowledge subjective experience as the basis for our mental models, including that of the observer-independent world of classical physics. This is why the hard problem of consciousness is called “hard”. And if you think that it should “obviously” be the other way around, meaning that this “scene” mental model is more fundamental than your subjective experiences, maybe you should reflect on why you developed this intuition in the first place. (It may be through extrapolating too much from your (first-person, subjective) experiences with objects that seemingly possess intrinsic, observer-independent properties, like the classical objects of everyday life.)
At this point it should be clearer why I am disagreeing with your post. Consciousness may be classical, it may be quantum, it may be something else. I have no issue with not having a soul and I don’t object to the idea of a bunch of gears and levers instantiating my consciousness merely because I find it a priori “preposterous” or “absurd” (though it is not a strong point of your theory). My issue is not with your conclusion, it’s precisely with your absolute certainty, which imo you support with cyclical argumentation based on weak premises. And I find it confusing that your post is receiving so much positive attention on a forum where epistemic hygiene is supposedly of paramount importance.
So in reading your comments of this post, I feel like I am reading comments made by a clone of my own mind. Though you articulate my views better than I can. This particular comment you make, I don’t think it gets The attention it deserves. It was pretty revolutionary for myself when I learned to think of almost every worldview at a model of reality. It’s most revolutionary when one realizes what is arguably an outdated Newtonian view to fall into this category of model. It really highlights that actual reality is at the least very hard to get at. This is a severe an issue with regards to consciousness.
It may be through extrapolating too much from your (first-person, subjective) experiences with objects that seemingly possess intrinsic, observer-independent properties, like the classical objects of everyday life.
Are you trying to say that quantum physics provides evidence that physical reality is subjective, with conscious observers having a fundamental role? Rob implicitly assumes the position advocated by The Quantum Physics Sequence, which argues that reality exists independently of observers and that quantum stuff doesn’t suggest otherwise. It’s just one of the many presuppositions he makes that’s commonly shared on here. If that’s your main objection, you should make that clear.
I would say that it is irrelevant for the points the post/Rob is trying to make whether consciousness is classical or quantum, given that conscious experience has, AFAIK, never been reported to be ‘quantum’ (i.e. that we don’t seem to experience superpositions or entanglement) and that we already have straightforward classical examples of lack of conscious continuity (namely: sleeping).
In the case of sleeping and waking up it is already clear that the currently awake consciousness is modeling its relation to past consciousnesses in that body through memories alone. Even without teleporters, copiers, or other universes coming into play, this connection is very fragile. How sure can a consciousness be that it is the same as the day before or as one during lucid parts of dreams? If you add brain malfunctions such as psychoses or dissociative drugs such as ketamine to the mix, the illusion of conscious continuity can disappear completely quite easily.
I like to word it like this: A consciousness only ever experiences what the brain that produces it can physically sense or synthesize.
With that as a starting point, modeling what will happen in the various thought experiments and analyses of conscious experience becomes something like this: “Given that there is a brain there, it will produce a consciousness, which will remember what is encoded in the structure of that brain and which will experience what that brain senses and synthesizes in that moment.”
There is no assumption that consciousness is classical in that, I believe. There is also no assumption of continuity in that, which I think is important as in my opinion that assumption is quite shaky and misdirects many discussions on consciousness. I’d say that the value in the post is in challenging that assumption.
In the case of sleeping and waking up it is already clear that the currently awake consciousness is modeling its relation to past consciousnesses in that body through memories alone.
The currently awake consciousness is located in the brain, which has physical continuity with its previous states. You don’t wake up as a different person because “you” are the brain (possibly also the rest of the body depending how it affects cognition but IDK) and the brain does not cease to function when you fall asleep.
I agree on the physical continuity of the brain, but I don’t think this transfers to continuity of the consciousness or its experience. It is defining “you” as that physical brain, rather than the conscious experience itself. It’s like saying that two waves are the same because they are produced by the same body of water.
Imagine significant modifications to your brain while you are asleep in such a way that your memories are vastly different, so much as to represent another person. Would the consciousness that is created on waking up experience a connection to the consciousness that that brain produced the day(s) before or to the manufactured identity?
Even you, now, without modifications, can’t say with certainty that your ‘yesterday self’ was experienced by the same consciousness as you are now (in the sense of identity of the conscious experience). It feels that way as you have memories of those experiences, but it may have been experienced by ‘someone else’ entirely. You have no way of discerning that difference (nor does anyone else).
The conscious experience is not extricable from the physical brain; it has your personality because the personality that you are is the sum total of everything in your brain. The identity comes from the brain; if it were somehow possible to separate consciousness from the rest of the mind, that consciousness wouldn’t still be you, because you’re the entire mind.
I would… not consider the sort of brain modification you’re describing to preserve physical continuity in the relevant sense? It sounds like it would, to create the described effects, involve significant alterations in portions of the brain wherein (so to speak) your identity is stored, which is not what normally happens when people sleep.
I think we are in agreement that the consciousness is tied to the brain. Claiming equivalency is not warranted, though: The brain of a dead person (very probably, I’m sure you’d agree) contains no consciousness. Let’s not dwell on this, though: I am definitely not claiming that consciousness exists outside of the brain, just that asserting physical continuity of the brain is not enough by itself to show continuity of conscious experience.
With regard to the modifications: Your line of reasoning runs into the classic issues of philosophical identity, as shown by the Ship of Theseus thought experiment or simpler yet, the Sorites paradox. We can hypothesize every amount of alterations from just modifying one atom to replacing the entire brain. Given your position, you’d be forced to choose an arbitrary amount of modifications that breaks the continuity and somehow changes consciousness A-modified-somewhat into consciousness B (or stated otherwise: from ‘you waking up a somewhat changed person’ to ‘someone else waking up in your body’).
Approaching conscious experience without the assumption of continuity but from the moment it exists in does not run into this problem.
First off, would you agree with my model of your beliefs? Would you consider it an accurate description?
Also, let me make clear that I don’t believe in cartesian souls. I, like you, lean towards physicalism, I just don’t commit to the explanation of consciousness based on the idea of the brain as a **classical** electronic circuit. I don’t fully dismiss it either, but I think it is worse on philosophical grounds than assuming that there is some (potentially minor) quantum effect going on inside the brain that is an integral part of the explanation for our conscious experience. However, even this doesn’t feel fully satisfying to me and this is why I say that I am agnostic. When responding to my points, you can assume that I am a physicalist, in the sense that I believe consciousness can probably be described using physical laws, with the added belief that these laws **may** not be fully understandable by humans. I mean this in the same way that a cat for example would not be able to understand the mechanism giving rise to consciousness, even if that mechanism turned out to be based on the laws of classical physics (for example if you can just explain consciousness as software running on classical hardware).
To expand upon my model of your beliefs, it seems to me that what you do is that you first reject cartesian souls and other such things on philosophical grounds and you thus favour physicalism. I agree on this. However I dont see why you are immediately assuming that physicalism means that your consciousness must be a result of classical computation. It could be the result of quantum computation. It could be something even subtler in some deeper theory of physics. At this point you may say that a quantum explanation may be more “unlikely” than a classical one, but I think that we both can agree that the “absurdity distance” between the two is much smaller than say a classical explanation and a soul-based one, and thus we now have to weigh the two much options much more carefully since we cannot dismiss one in favour of the other as easily. What I would like to argue is that a quantum-based consciousness is philosophically “nicer” than a classical one. Such an explanation does not violate physicalism, while at the same time rendering a lot of points of your post invalid.
Let’s start by examining the copier argument again but now with the assumption that conscious experience is the result of quantum effects in the brain and see where it takes us. In this case, to fully copy a consciousness from one place to another you would have to copy an unknown quantum state. This is physically impossible even in theory, based on the no-cloning theorem. Thus the “best” copier that you can have is the copier from my previous comment, which just copies the classical connectivity of the brain and all the current and voltages etc, but which now fails to copy the part that is integral to **your** first person experience. So what would be your first person experience if you were to enter the room? You would just go in, hear the scanner work, get out. You can do this again and again and again and always find yourself experiencing getting out of the same initial room. At the same time the copier does create copies of you, but they are new “entities” that share the same appearance as you and which would approximate to some (probably high) degree your external behaviour. These copies may or may not have their own first person experience (and we can debate this further) but this does not matter for our argument. Even if they have a first person experience, it would be essentially the same as the copier just creating entirely new people while leaving your first person experience unchanged. In this way, you can step into the room with zero expectation that you may walk out of a room on the other side of the copier, in the same way that you dont expect to suddenly find yourself in some random stranger’s body while going about your daily routine. Even better, this belief is nicely consistent with physicalism, while still not violating our intuitions that we have private and uncopiable subjective experiences. It also doesn’t force us to believe that a bunch of water pipes or gears functioning as a classical computer can ever have our own first person experience. Going even further, unknown quantum states may not be copyable but they are transferable (see quantum teleportation etc), meaning that while you cannot make a copier you can make a transporter, but you always have to be at only one place at each instant.
Let me emphasize again that I am not arguing **for** quantum consciousness as a solution. I am using it as an example that a “philosophically nicer” physicalist option exists compared to what I assume you are arguing for. From this perspective, I don’t see why you are so certain about the things you write in your post. In particular, you make a lot of arguments based on the properties of “physics”, which in reality are properties of classical physics together with your assumption that consciousness must be classical. When I said that I find issue with the fact that you start from an unstated assumption, I didnt expect you to argue against cartesian dualism. I expected you to start from physicalism and then motivate why you chose to only consider classical physics. Otherwise, the argumentation in your post seems lacking, even if I start from the physicalist position. To give one example of this:
You say that “there isn’t an XML tag in the brain saying `this is a new brain, not the original`” . By this I assume you mean that the physical state of the brain is fungible, it is copyable, there is nothing to serve as a label. But this is not a feature of physics in general. An unknown quantum state cannot be copied, it is not fungible. My model of what you mean: “(I assume that) first person experience can be fully attributed to some structure of the brain as a classical computer. It can be fully described by specifying the connectivity of the neurons and the magnitudes of the currents and voltages between each point. Since (I assume) consciousness physically manifests as a classical pattern and since classical patterns can be copied, then by definition there can be many copies of “the same” consciousness”. Thus, what you write about XML tags is not an argument for your position—it is not imposed to you by physics to consider a fungible substrate for consciousness - it is just a manifestation of your assumption. It’s cyclical. A lot of your arguments which invoke “physics” are like that.
Why would the laws of physics conspire to vindicate a random human intuition that arose for unrelated reasons?
We do agree that the intuition arose for unrelated reasons, right? There’s nothing in our evolutionary history, and no empirical observation, that causally connects the mechanism you’re positing and the widespread human hunch “you can’t copy me”.
If the intuition is right, we agree that it’s only right by coincidence. So why are we desperately searching for ways to try to make the intuition right?
Why is this an advantage of a theory? Are you under the misapprehension that “hypothesis H allows humans to hold on to assumption A” is a Bayesian update in favor of H even when we already know that humans had no reason to believe A? This is another case where your theory seems to require that we only be coincidentally correct about A (“sufficiently complex arrangements of water pipes can’t ever be conscious”), if we’re correct about A at all.
One way to rescue this argument is by adding in an anthropic claim, like: “If water pipes could be conscious, then nearly all conscious minds would be instantiated in random dust clouds and the like, not in biological brains. So given that we’re not Boltzmann brains briefly coalescing from space dust, we should update that giant clouds of space dust can’t be conscious.”
But is this argument actually correct? There’s an awful lot of complex machinery in a human brain. (And the same anthropic argument seems to suggest that some of the human-specific machinery is essential, else we’d expect to be some far-more-numerous observer, like an insect.) Is it actually that common for a random brew of space dust to coalesce into exactly the right shape, even briefly?
You’re missing the bigger picture and pattern-matching in the wrong direction. I am not saying the above because I have a need to preserve my “soul” due to misguided intuitions. On the contrary, the reason for my disagreement is that I believe you are not staring into the abyss of physicalism hard enough. When I said I’m agnostic in my previous comment, I said it because physics and empiricism lead me to consider reality as more “unfamiliar” than you do (assuming that my model of your beliefs is accurate). From my perspective, your post and your conclusions are written with an unwarranted degree of certainty, because imo your conception of physics and physicalism is too limited. Your post makes it seem like your conclusions are obvious because “physics” makes them the only option, but they are actually a product of implicit and unacknowledged philosophical assumptions, which (imo) you inherited from intuitions based on classical physics. By this I mean the following:
It seems to me that when you think about physics, you are modeling reality (I intentionally avoid the word “universe” because it evokes specific mental imagery) as a “scene” with “things” in it. You mentally take the vantage point of a disembodied “observer/narrator/third person” observing the “things” (atoms, radiation etc) moving, interacting according to specific rules and coming together to create forms. However, you have to keep in mind that this conception of reality as a classical “scene” that is “out there” is first and foremost a model, one that is formed from your experiences obtained by interacting specifically with classical objects (biliard balls, chairs, water waves etc). You can extrapolate from this model and say that reality truly is like that, but the map is not the territory, so you at least have to keep track of this philosophical assumption. And it is an assumption, because “physics” doesn’t force you to conclude such a thing. Seen through a cautious, empirical lens, physics is a set of rules that allows you to predict experiences. This set of rules is produced exclusively by distilling and extrapolating from first-person experiences. It could be (and it probably is) the case that reality is ontologically far weirder than we can conceive, but that it still leads to the observed first-person experiences. In this case, physics works fine to predict said experiences, and it also works as an approximation of reality, but this doesn’t automatically mean that our (merely human) conceptual models are reality. So, if we want to be epistemically careful, we shouldn’t think “An apple is falling” but instead “I am having the experience of seeing an apple fall”, and we can add extra philosophical assumptions afterwards. This may seem like I am philosophizing too much and being too strict, but it is extremely important to properly acknowledge subjective experience as the basis for our mental models, including that of the observer-independent world of classical physics. This is why the hard problem of consciousness is called “hard”. And if you think that it should “obviously” be the other way around, meaning that this “scene” mental model is more fundamental than your subjective experiences, maybe you should reflect on why you developed this intuition in the first place. (It may be through extrapolating too much from your (first-person, subjective) experiences with objects that seemingly possess intrinsic, observer-independent properties, like the classical objects of everyday life.)
At this point it should be clearer why I am disagreeing with your post. Consciousness may be classical, it may be quantum, it may be something else. I have no issue with not having a soul and I don’t object to the idea of a bunch of gears and levers instantiating my consciousness merely because I find it a priori “preposterous” or “absurd” (though it is not a strong point of your theory). My issue is not with your conclusion, it’s precisely with your absolute certainty, which imo you support with cyclical argumentation based on weak premises. And I find it confusing that your post is receiving so much positive attention on a forum where epistemic hygiene is supposedly of paramount importance.
So in reading your comments of this post, I feel like I am reading comments made by a clone of my own mind. Though you articulate my views better than I can. This particular comment you make, I don’t think it gets The attention it deserves. It was pretty revolutionary for myself when I learned to think of almost every worldview at a model of reality. It’s most revolutionary when one realizes what is arguably an outdated Newtonian view to fall into this category of model. It really highlights that actual reality is at the least very hard to get at. This is a severe an issue with regards to consciousness.
Are you trying to say that quantum physics provides evidence that physical reality is subjective, with conscious observers having a fundamental role? Rob implicitly assumes the position advocated by The Quantum Physics Sequence, which argues that reality exists independently of observers and that quantum stuff doesn’t suggest otherwise. It’s just one of the many presuppositions he makes that’s commonly shared on here. If that’s your main objection, you should make that clear.
I would say that it is irrelevant for the points the post/Rob is trying to make whether consciousness is classical or quantum, given that conscious experience has, AFAIK, never been reported to be ‘quantum’ (i.e. that we don’t seem to experience superpositions or entanglement) and that we already have straightforward classical examples of lack of conscious continuity (namely: sleeping).
In the case of sleeping and waking up it is already clear that the currently awake consciousness is modeling its relation to past consciousnesses in that body through memories alone. Even without teleporters, copiers, or other universes coming into play, this connection is very fragile. How sure can a consciousness be that it is the same as the day before or as one during lucid parts of dreams? If you add brain malfunctions such as psychoses or dissociative drugs such as ketamine to the mix, the illusion of conscious continuity can disappear completely quite easily.
I like to word it like this: A consciousness only ever experiences what the brain that produces it can physically sense or synthesize.
With that as a starting point, modeling what will happen in the various thought experiments and analyses of conscious experience becomes something like this: “Given that there is a brain there, it will produce a consciousness, which will remember what is encoded in the structure of that brain and which will experience what that brain senses and synthesizes in that moment.”
There is no assumption that consciousness is classical in that, I believe. There is also no assumption of continuity in that, which I think is important as in my opinion that assumption is quite shaky and misdirects many discussions on consciousness. I’d say that the value in the post is in challenging that assumption.
The currently awake consciousness is located in the brain, which has physical continuity with its previous states. You don’t wake up as a different person because “you” are the brain (possibly also the rest of the body depending how it affects cognition but IDK) and the brain does not cease to function when you fall asleep.
I agree on the physical continuity of the brain, but I don’t think this transfers to continuity of the consciousness or its experience. It is defining “you” as that physical brain, rather than the conscious experience itself. It’s like saying that two waves are the same because they are produced by the same body of water.
Imagine significant modifications to your brain while you are asleep in such a way that your memories are vastly different, so much as to represent another person. Would the consciousness that is created on waking up experience a connection to the consciousness that that brain produced the day(s) before or to the manufactured identity?
Even you, now, without modifications, can’t say with certainty that your ‘yesterday self’ was experienced by the same consciousness as you are now (in the sense of identity of the conscious experience). It feels that way as you have memories of those experiences, but it may have been experienced by ‘someone else’ entirely. You have no way of discerning that difference (nor does anyone else).
The conscious experience is not extricable from the physical brain; it has your personality because the personality that you are is the sum total of everything in your brain. The identity comes from the brain; if it were somehow possible to separate consciousness from the rest of the mind, that consciousness wouldn’t still be you, because you’re the entire mind.
I would… not consider the sort of brain modification you’re describing to preserve physical continuity in the relevant sense? It sounds like it would, to create the described effects, involve significant alterations in portions of the brain wherein (so to speak) your identity is stored, which is not what normally happens when people sleep.
I think we are in agreement that the consciousness is tied to the brain. Claiming equivalency is not warranted, though: The brain of a dead person (very probably, I’m sure you’d agree) contains no consciousness. Let’s not dwell on this, though: I am definitely not claiming that consciousness exists outside of the brain, just that asserting physical continuity of the brain is not enough by itself to show continuity of conscious experience.
With regard to the modifications: Your line of reasoning runs into the classic issues of philosophical identity, as shown by the Ship of Theseus thought experiment or simpler yet, the Sorites paradox. We can hypothesize every amount of alterations from just modifying one atom to replacing the entire brain. Given your position, you’d be forced to choose an arbitrary amount of modifications that breaks the continuity and somehow changes consciousness A-modified-somewhat into consciousness B (or stated otherwise: from ‘you waking up a somewhat changed person’ to ‘someone else waking up in your body’).
Approaching conscious experience without the assumption of continuity but from the moment it exists in does not run into this problem.