I think the author is misunderstanding the XKCD comic about rocks [1] (or maybe I am). Just because it's possible to run a simulation of the universe on rocks, doesn't mean that rocks are conscious or turing complete. You can't forget about the person who is manipulating the rocks. The system as a whole is turing complete. Likewise with the bar of iron example that the author gave, you can't forget about the person interpreting the atoms in the bar of iron. The system as a whole is turing complete (and also naturally conscious, because the person doing the interpretation is conscious).
And there is nothing physical necessary to represent such systems. You can simulate turing complete systems inside turing complete systems [2]. So I don't see why consciousness has to be a "physical phenomenon" as the author claims.
I have an inherent problem with these discussions: I'm not convinced a simulation can be conscious.
There's an xkcd comic titled "A Bunch of Rocks" at https://www.xkcd.com/505/. Could dropping rocks in the sand to simulate a turing machine produce a conscious being? If not, why can a computer?
I love the bunch of rocks example and think about it a lot.
If a simulation cannot produce consciousness, what is special about life that makes it unrepresentable with physics? Where is the boundary between a conscious system and a non-conscious one?
Conscious minds certainly seem bound by their physicality, you can figure out how feelings and experiences are represented molecularly and electrochemically and affect those feelings and experiences experimentally. So far we've not found anything that cannot be broken down into physics (not to say we won't), but if we assume there's nothing else _but_ physics – then I think we're left with:
- The physics consciousness relies upon is fundamentally uncomputable
- Consciousness _is_ computable and all the weird consequences that follow (like sand computers) are true
I lean towards the second option, but I struggle to understand it in any intuitive sense.
What are your thoughts on why a simulation cannot be conscious?
Wouldn't that mean a pile of sand on the ground or a pile of rocks in the desert are also conscious? Because viewed the right way those can be representations of arbitrarily complex turing machines (see https://xkcd.com/505/)
In the comic, I believe the idea is that this entity is moving the rocks by hand, but following the rules of computing which slowly, but steadily, creates the world as a computer simulation. And in this case, the qualia would be an emergent property of that simulation, but how that happens or whether it happens at all is a much bigger debate...
I don't get this either. I used to think about these experiments and my conclusions are completely opposite. Any physical medium that runs the right program would be conscious. And the right program is probably a very broad category.
>It already seems implausible to me that a vast desert of rocks being manipulated into various patterns is conscious. What exactly is conscious here? What happens if I accidentally kick a rock to the side — have I killed whatever ghostly being inhabits these rocks?
If you kick a rock to the side it's probably analogous to making someone's neuron misfire. If the pebble computer is as sturdy as a human brain then there would be probably no noticeable effect.
The problem with this view is Hilary Putnam's "a rock implements every finite state automata". (Nicely explained, with a rebuttal in [0].)
It's an attractive idea that some thing has agency (or consciousness, or whatever property you want to define) to the extent it does some sort of computation. But then you have to go figure out what it means for something to do that computation. That turns out to be extremely difficult; most things can be interpreted as computing most other things.
The rockputer comprises both the rocks and the mechanisms for moving the rocks in response to input. If the rock moving mechanism is structured properly, then the rock movement patterns could adapt to changes in the inputs to the overall rockputer system.
The level of complexity of the "passive" components of the system (i.e. the rocks) is irrelevant to whether or not the system can effect conscious-seeming behaviour when acting dynamically. Analogously, the underlying components of people, i.e. atoms, are clearly quite dumb on their own. When those atoms are allowed to evolve collectively over time, according to dynamics dictated by basic physical laws, conscious-seeming behaviour magically appears.
You can't deny the possibility of a conscious rockputer just by considering properties of the rocks.
On the first issue, that's the Boltzmann's Brain proposition, and well, yes. Given infinite monkeys, you'll get Shakespear. I don't see what that has to do with whether consciousness is computational or not. It certainly doesn't refute it.
>Just to be clear, you don't doubt that a sufficiently large field of rocks is conscious as long as it is performing the same computation as a brain?
No I don't, for the same reason that if you slowed down my metabolism by a trillion times, I would still be conscious. I wouldn't seem conscious to you, but that's a problem with your perception, not with my nature. I'd just be conscious very slowly. It wouldn't fundamentally change the nature of who or what I am. For rocks interacting according to rules, substitute atoms. Is a rock any more or less inanimate than an atom? This is all just materialism 101.
This is trivially true as you state it; that's why I added the qualifier "in appropriate ways". Not all interactions will produce consciousness. One obvious difference between us and your hypothetical "rockputer" is that the "rockputer" can't change its behavior based on its inputs in a way that improves its chances of survival; rocks simply aren't built that way. Neither are star systems or galaxies. But we are.
I find this argument completely unconvincing. The mapping in a case like the iron bar is entirely ephemeral, pertaining only for an instant. For this argument to be valid you’d have to be able to persistently map the iron bar, or waterfall, to all ongoing transformations of states in the running program, using one single consistent mapping. Otherwise all you have is a snapshot of state, not an ongoing process. To achieve a persistent mapping for a significant time you'd probably need an iron bar something like size of the observable universe, at which point we're in Boltzmann's Brain territory.
This argument is in the article as well and I’ve seen it from Searle too:
“A simulation of a brain cannot produce consciousness any more than a simulation of the weather can produce rain.”
This is making the unstated prior assumption that consciousness is not a computation. If it is a computation then conciousness is not like weather itself, it’s like the simulation. Me imagining having a shower doesn’t make anything wet either. So is my imagination more like the weather, or more like the simulation of it?
As for doubting the field of rocks can be conscious, that’s redundant, you might as well say a 3D field of atoms cannot be conscious, such as a brain for example. Talking about computation and consciousness is a sideshow, this is anti-materialism by the back door. Nothing more.
I can accept (and to be honest even like) the idea, that consciousness somehow emerges from the complex structures in an animal brain, that there is no soul, no other planes of reality, no special quantum phenomena needed, etc.
Maybe we could create a synthetic artificial conscious mind. At worst we could simulate a full human brain at whatever level is necessary. I can accept that.
What's crazy to me is the following: It's not the computer that's conscious. Instead, the computation itself is conscious. And the computation is obviously matter-independent. As a thought experiment it would be possible to compute it on paper and those pen and paper calculations would be conscious. Or pebbles in a desert XKCD style.
This isn't clear at all how it reaches the conclusion...it seems to jump to its conclusion with no justification other than "anything else is absurd because I said so".
Of course the conclusion is absurd, because the premise: someone executing assembly instructions and writing results on a ledger could do so at a scale capable of simulating consciousness over any significant time scale. The time required for a person to do such simulation of just 1 second of conscious existence would likely take more than their lifetime.
Consciousness is universally present. That doesn't mean rocks are conscious, no more than it means sand can compute. And yet we're communicating over computing sand, aren't we?
So fundamentally I agree with the arguments presented in this post, but I find the presentation confusing and somewhat lacking in rigor. In particular I was confused by his description of the iron bar as a computer because he didn't actually explain how it computed anything. I think that to map a physical system to an abstract Turing Machine you need more than a way to represent bits. You also have to define how to do computations with them. In other words you need something like logic gates.
Nonetheless I do think that there is a sense in which computation only has meaning in relation to an external observer, but I think that is an idea that requires some more exploration. It is also a question that I think can be addressed by the methods of Theoretical Computer Science.
Beyond that however the strongest argument I can give for why consciousness is not a computation is that (like the post author says) computation is fundamentally about the manipulation of symbols (which means it is closely related to language, whether natural or formal) and qualia (ie. conscious experiences) cannot be represented symbolically (ie. linguistically). To be clear when I say "represented by" I mean "fully represented by" or "reducible to". If qualia were reducible to a symbolic representation then there should be some linguistic utterance which would cause you to experience the sensation of the pain of burning your finger on the stove. Obviously such utterances do not exist. In fact the closest thing in human literature to such an utterance would be a magic spell, which I'm sure you agree, aren't real.
Yeah, the author claims that consciousness is observer independent, but then creates systems that depend on an "observer" (or rather, an interpreter) to make the system turing complete. The bar of iron isn't conscious or turing-complete just because one person can interpret it so. The bar of iron + the interpreter form a complete system. And in fact the bar of iron is really not doing anything in this case, it's the interpreter doing all the work, so it's more like saying "this human interpreter is conscious". Not a very insightful conclusion.
There's always something to interact with. If you had a conscious being made out of star systems, it wouldn't meaningfully interact with anything within our lifetime, but over billions of billions of years, it would presumably shift entire galaxies. The rockputer just needs inputs that operate at its own scale, like the shape of the coastlines it's expanding into, information about geological processes, another rockputer competing for territory, and so on. Alternatively you could simulate a whole universe using these rocks, and feed simulated inputs to the being.
Of course, part of the difficulty of imagining a conscious rockputer is that it's also pretty hard to imagine its inputs :)
The problem I have with this is that you can then claim that anything and everything is conscious.
Create a turing machine out of marbles and levers, and it's suddenly "conscious" with the right configuration. You really believe that given enough space, a bunch of marbles running along tracks bouncing off levers can become aware that it is a giant marble machine?
The atoms in one pocket of the sun's chaotic fusion reaction might randomly and momentarily behave like an intelligent quantum computer - does that mean the sun is momentarily conscious from time to time?
> it must be possible to feed in any program, after the mapping has been defined.
This is absolutely correct and gets to the heart of it. We define a mapping and we can imagine even setting some of the spins of the atoms in the bar to input a particular "program." Then we sit back and watch the spins randomly flip and see if they correspond to what a universal Turing machine would do.
The reason that a hot iron bar in practice is not a computer is that there is no way we can easily find the correct mapping before we observe the bar. The process of finding this mapping will take more work than the computation itself. (I think this is what you mean in saying "the computation is really happening in the mapping itself.") So for our purposes it's useless for performing any computations. Nevertheless, some mapping from the bar's states to a Turing machine executing the program we've given it exists.
This is why this is different for the case of consciousness. Because consciousness exists independent of whether or not we're aware of it, it doesn't matter whether or not we can find this mapping beforehand. It just matters that such a mapping exists.
It would be different if I made the claim that the iron bar is sorting a list. I might say, "there exists a mapping of the states of the iron bar to a Turing machine running quicksort. Therefore the iron bar is sorting a list." The appropriate response would be "So what? If I consider all random permutations of the list, obviously one of them will be sorted --- but how does that help me find it? It takes me the same amount of work to find this mapping as it does to sort the list."
But if we are to say that consciousness is fundamentally a computational phenomenon, it doesn't matter if you find the mapping or not --- it exists independent of you.
> If one believes that consciousness can emerge from software on a computer alone, it also follows that consciousness can emerge from placing rocks in a certain pattern following instructions in a book.
I don't think this is as absurd as it sounds. I think it was Dennett who said our intuition about consciousness is pretty sensitive to timing. The rock construction you describe would "think" a billion times slower than a human brain, and there is something unsettling or unintuitive about a consciousness that operates in slow motion. I would expect extremely fast-paced AI to think that the idea that human beings are conscious is similarly absurd.
Also, consciousness "feels" like it's ineffable, so it makes sense that we would have an inherent bias against understanding it as a process. There is something we see in our consciousness that we simply cannot wrap our minds around in any way (possibly because we're hallucinating it).
So yes, I would bite the bullet on this: consciousness could emerge from placing rocks in a certain pattern following instructions in a book. It would just be an excruciatingly "slow" consciousness.
And there is nothing physical necessary to represent such systems. You can simulate turing complete systems inside turing complete systems [2]. So I don't see why consciousness has to be a "physical phenomenon" as the author claims.
[1]: https://xkcd.com/505/
[2]: https://youtu.be/xP5-iIeKXE8
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