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.
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.