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1811A starting point is self-reports. If I truthfully say “I see my wristwatch”, then, somewhere in the chain of causation that eventually led to me uttering those words, there’s an actual watch, and photons are bouncing off it and entering my eyes then stimulating neurons etc.
So by the same token, if I say “your phenomenal consciousness is a salty yellow substance that smells like bananas and oozes out of your bellybutton”, and then you reply “no it isn’t!”, then let’s talk about how it is that you are so confident about that.
(I’m using “phenomenal consciousness” as an example, but ditto for “my sense of self / identity” or whatever else.)
So here, you uttered a reply (“No it isn’t!”). And we can assume that somewhere in the chain of causation is ‘phenomenal consciousness’ (whatever that is, if anything), and you were somehow introspecting upon it in order to get that information. You can’t know things in any other way—that’s the basic, hopefully-obvious point that I understand Eliezer was trying to make here.
Now, what’s a ‘chain of causation’, in the relevant sense? Let’s start with a passage from Age of Em:
The brain does not just happen to transform input signals into state changes and output signals; this transformation is the primary function of the brain, both to us and to the evolutionary processes that designed brains. The brain is designed to make this signal processing robust and efficient. Because of this, we expect the physical variables (technically, “degrees of freedom”) within the brain that encode signals and signal-relevant states, which transform these signals and states, and which transmit them elsewhere, to be overall rather physically isolated and disconnected from the other far more numerous unrelated physical degrees of freedom and processes in the brain. That is, changes in other aspects of the brain only rarely influence key brain parts that encode mental states and signals.
In other words, if your body temperature had been 0.1° colder, or if you were hanging upside down, or whatever, then the atoms in your brain would be configured differently in all kinds of ways … but you would still say “no it isn’t!” in response to my proposal that maybe your phenomenal consciousness is a salty yellow substance that oozes out of your bellybutton. And you would say it for the exact same reason.
This kind of thinking leads to the more general idea that the brain has inputs (e.g. photoreceptor cells), outputs (e.g. motoneurons … also, fun fact, the brain is a gland!), and algorithms connecting them. Those algorithms describe what Hanson’s “degrees of freedom” are doing from moment to moment, and why, and how. Whenever brains systematically do characteristically-brain-ish things—things like uttering grammatical sentences rather than moving mouth muscles randomly—then the explanation of that systematic pattern lies in the brain’s inputs, outputs, and/or algorithms. Yes, there’s randomness in what brains do, but whenever brains do characteristically-brainy-things reliably (e.g. disbelieve, and verbally deny, that your consciousness is a salty yellow substance that oozes out of your bellybutton), those things are evidently not the result of random fluctuations or whatever, but rather they follow from the properties of the algorithms and/or their inputs and outputs.
That doesn’t quite get us all the way to computationalist theories of consciousness or identity. Why not? Well, here are two ways I can think of to be non-computationalist within physicalism:
- One could argue that consciousness & sense-of-identity etc. are just confused nonsense reifications of mental models with no referents at all, akin to “pure white” [because white is not pure, it’s a mix of wavelengths]. (Cf. “illusionism”.) I’m very sympathetic to this kind of view. And you could reasonably say “it’s not a computationalist theory of consciousness / identity, but rather a rejection of consciousness / identity altogether!” But I dunno, I think it’s still kinda computationalist in spirit, in the sense that one would presumably instead make the move of choosing to (re)define ‘consciousness’ and ‘sense-of-identity’ in such a way that those words point to things that actually exist at all (which is good), at the expense of being inconsistent with some of our intuitions about what those words are supposed to represent (which is bad). And when you make that move, those terms almost inevitably wind up pointing towards some aspect(s) of brain algorithms.
- One could argue that we learn about consciousness & sense-of-identity via inputs to the brain algorithm rather than inherent properties of the algorithm itself—basically the idea that “I self-report about my phenomenal consciousness analogously to how I self-report about my wristwatch”, i.e. my brain perceives my consciousness & identity through some kind of sensory input channel, and maybe also my brain controls my consciousness & identity through some kind of motor or other output channel. If you believe something like that, then you could be physicalist but not a computationalist, I think. But I can’t think of any way to flesh out such a theory that’s remotely plausible.
I’m not a philosopher and am probably misusing technical terms in various ways. (If so, I’m open to corrections!)
(Note, I find these kinds of conversations to be very time-consuming and often not go anywhere, so I’ll read replies but am pretty unlikely to comment further. I hope this is helpful at all. I mostly didn’t read the previous conversation, so I’m sorry if I’m missing the point, answering the wrong question, etc.)
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I think the standard argument that quantum states are not relevant to cognitive processes is The importance of quantum decoherence in brain processes. This is enough to convince me that going through a classical teleporter or copying machine would preserve my identity, and in the case of a copying machine I would experience an equal subjective probability of coming out as the original or the copy. It also seems to strongly imply than mind uploading into some kind of classical artificial machine is possible, since it's unlikely that all or even most of the classical properties of the brain are essential. I agree that there's an open question about whether mind emulation on any arbitrary substrate (like, for instance, software running on CMOS computer chips) preserves identity even if it shows the same behavior as the original.
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20I'm going to give an argument in favor of computationalism as a theory of identity, but first I'm going to set up some of the stuff that I take as background, but others may not, and will hopefully illuminate related issues.
I believe computationalism is a very general way to look at effectively everything, because a model of computation can be extremely expressive, and a big reason for why philosophical debates go nowhere is that they don't realize that expressive enough models of computation can essentially trivialize any problem they set up, solely through the expressiveness of the model, so it's very important to realize that philosophical problems end up trivial if we allow ourselves to be unconstrained.
More here:
http://www.amirrorclear.net/academic/ideas/simulation/index.html
http://www.amirrorclear.net/academic/research-topics/other-topics/hypercomputation.html
https://arxiv.org/abs/1806.08747
This also answers andeslodes's point around physicalism, as the physicalist ontology is recoverable as a special case of the computationalist ontology, where we care about each instantiation, and we also care about low-level things that are always simulatable by powerful models of computation.
However, I do think there's an actually non-trivial question here, about why can we be confident that the brain is copyable by a realistic classical computer with reasonable fidelity, when in principle it could be using quantum mechanics for a non-trivial portion of the brain's operations, which would complicate mind uploading massively?
My general answer here is that quantum computation in warm, wet environments is very hard to error-correct at scale, and the biologically plausible ways to do such a thing fundamentally cannot scale to make a quantum computer in our brains, and anything that is fragile in the presence of noise/error is basically unevolvable by default, because there's no incremental way to make a quantum computer inside a human brain.
That's why we can reasonably use classical models of the brain without it leaving a lot out.
As far as my own theory of identity/consciousness goes, I think the gooder regulator theorem gives am answer on why we would want to have a self-model of ourselves, and I'd argue this is the seed from which consciousness/identity grows, so computations meeting the requirements in the gooder regulator theorem can certainly have identities, which means that I do think Rob Bensinger is more or less right about this topic, modulo caveats.
I'm inspired by @Ape in the coat here on these points:
And my own comments on the topic:
The caveats are given below:
https://www.lesswrong.com/posts/Dx9LoqsEh3gHNJMDk/fixing-the-good-regulator-theorem#Takeaway
The main functions of consciousness/identity is to give a consistent abstraction across time so that cooperation and deal making become possible, at least for causal decision theories, at least without stuff like provability logic/program equilibrium, which isn't really evolvable (for other theories like logical decision theory, cooperation in one-shot PD is very possible, but that comes about because they view their identities as closer to an isomorphism class of a program, and consider all instances combined as 1 program, so long as they are functionally equivalent), combined with the necessity of self-modeling yourself in order to get a good outcome, though the self-model here is the more important part for me on consciousness, and the abstraction to a consistent identity comes later.
So for my purposes, I think Rob Bensinger is mostly right about the philosophical underpinnings of identity/consciousness, but I don't blame TAG, @andeslodes and @sunwillrise for questioning the consensus, since the consensus was frankly poorly argued, and @Rob Bensinger was acting far too much like a soldier rather than a scout in the comments section.
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I think we should disentangle "consciousness" from "identity" in general and when talking about computationalism in particular.
I don't think there is any reasonable alternative to computationalism when we are talking about the nature of consciousness. But this doesn't seem to actually imply that my "identity", whatever it is, will be necessary preserved during teleportation or uploading. I think at our current state of undertstanding, it's quite coherent to be computationalist about consciousness and eliminativist towards identity.
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Computationalism is an ethical theory, so it is fine for it to be based on high-level abstractions - ethics is arbitrary.
A few months ago, Rob Bensinger made a rather long post (that even got curated) in which he expressed his views on several questions related to personal identity and anticipated experiences in the context of potential uploading and emulation. A critical implicit assumption behind the exposition and reasoning he offered was the adoption of what I have described as the "standard LW-computationalist frame." In response to me highlighting this, Ruben Bloom said the following:
However, as I pointed out in that thread, the lack of argumentation or discussion of this particular assumption throughout the history of the site means it's highly questionable to say that assuming it is "reasonable enough":
TAG himself made a similar and important point in a different comment on the same post:
And, indeed (ironically enough), in response to andesoldes's excellent distillation of Rob's position and subsequent detailed and concrete explanation of why it seems wrong to have this degree of confidence in his beliefs, Bensinger yet again replied in a manner that seemed to indicate he thought he was arguing against a dualist who thought there was a little ghost inside the machine, an invisible homunculus that violated physicalism:
But, as andesoldes later ably pointed out:
More specifically, as I wrote in response to Seth Herd, "[the] standard LW-computationalist frame reads to me as substantively anti-physicalist and mostly unreasonable to believe in" for reasons I gave in my explanation to Bloom:
The accuracy of this interpretation of the LW-computationalist view seems to have been confirmed by its proponents, implicitly by Bensinger continuing the conversation with andesoldes without mentioning any disagreement when the latter explicitly asked him "First off, would you agree with my model of your beliefs? Would you consider it an accurate description?" and by cousin_it saying that "uploading [going] according to plan" means "the map of your neurons and connections has been copied into a computer", and explicitly by Seth Herd claiming that "your mind is a pattern instantiated in matter" and by Bloom, who wrote the following:
(Emphasis mine.)
When Seth Herd restated computationalist conclusions, once again without much argumentation ("Noncomputational physicalism sounds like it's just confused. Physics performs computations and can't be separated from doing that. Dual aspect theory is incoherent because you can't have our physics without doing computation that can create a being that claims and experiences consciousness like we do"), I summarized a relevant part of my skepticism as follows:
So, to finish up the exposition and background behind this question, what are the actual arguments in favor of the computationalist thesis? If you agree with the latter philosophy,[1] why do you not think it to be the case that computationalism is anti-physicalist by failing a basic map-territory distinction due to how it reifies ideas like "computation" as being parts of the territory as opposed to mere artifacts of a mathematical model that attempts, imperfectly and lossily, to approximate reality?
In my current model of this situation, I have some strong suspicions about the reasons why LW converged on this worldview despite the complete lack of solid argumentation in its favor, but I prefer to withhold the psychoanalysis and pathologizing of my interlocutors (at least until after the object-level matters are resolved satisfactorily).