Shawn Mikula on Brain Preservation Protocols and Extensions

I'm not sure I understand you. What do you mean by the system of equations being undetermined. Are you saying to take the same animated gif and not alter the actual physics in any way, and just refer to it differently? That obviously doesn't change anything. You need to alter the causal structure.

My problem with non-machine functionalism is that any reason we have to say we're conscious would equally apply to a simulation. If you one day found out that you were really a simulation would you decide your consciousness is an illusion, or figure you must have gotten it backwards which one is conscious, and it's the simulations that are conscious and the real people that are p-zombies?

You seem to be discussing in good faith here, and I think it's worth continuing so we can both get a better idea of what the other is saying. I think differing non-verbal intuitions drive a lot of these debates, and so to avoid talking past one another it's best to try to zoom in on intuitions and verbalize them as much as possible. To that end (keeping in mind that I'm still very confused about consciousness in general): I think a large part of what makes me a machine functionalist is an intuition that neurons...aren't that special. Like, you view the China Brain argument as a reductio because it seems so absurd. And I guess I actually kind of agree with that, it does seem absurd that a bunch of people talking to one another via walkie-talkie could generate consciousness. But it seems no more absurd to me than consciousness being generated by a bunch of cells sending action potentials to one another. Why should we have expected either of those processes to generate consciousness? In both cases you just have non-mental, syntactical operations taking place. If you hadn't heard of neurons, wouldn't they also seem like a reductio to you?

What it comes down to is that consciousness seems mysterious to me. And (on an intuitive level) it kind of feels like I need to throw something "special" at consciousness to explain it. What kind of special something? Well, you could say that the brain has the special something, by virtue of the fact that it's made of neurons. But that doesn't seem like the right kind of specialness to me, somehow. Yes, neurons are special in that they have a "unique" physico-chemical causal structure, by why single that out? To me that seems as arbitrary as singling out only specific types of atoms as being able to instantiate consciousness (which some people seem to do, and which I don't think you're doing, correct?). It just seems too contingent, too earth-specific an explanation. What if you came across aliens that acted conscious but didn't have any neurons or a close equivalent? I think you'd have to concede that they were conscious, wouldn't you? Of course, such aliens may not exist, so I can't really make an argument based on that. But still - really, the answer to the mystery of consciousness is going to come down to the fact that particular kinds of cells evolved in earth animals? Not special enough! (or so say my intuitions, anyway)

So I'm led in a different direction. When I look at the brain and try to see what could be generating consciousness, what pops out to me is that the brain does computations. It has a particular pattern, a particular high-level causal structure that seems to lie at the heart of its ability to perform the amazing mental feats it does. The computations it performs are implemented on neurons, of course, but that doesn't seem central to me - if they were implemented on some other substrate, the amazing feats would still get done (Shakespeare would still get written, Fermat's Last Theorem would still get proved). What does seem central, then? Well, the way the neurons are wired up. My understanding (correct me if I'm wrong) is that in a neural network such as the brain, any given neuron fires iff all the inhibitory and excitatory inputs feeding into the neuron exceed some threshold. So roughly speaking, any given brain can be characterized by which neurons are connected to which other neurons, and what the weights of those connections are, yes? In that case (forgetting consciousness for a moment), what really matters in terms of creating a brain that can perform impressive mental feats is setting up those connections in the right way. But that just amounts to defining a specific high-level causal structure - and yes, that will require you to define a set of counterfactual dependencies (if neurons A and B had fired, then neuron C wouldn't have fired, etc). I was kind of surprised that you were surprised that we brought up counterfactual dependence earlier in the discussion. For one I think it's a standard-ish way of defining causality in philosophy (it's at least the first section in the wikipedia article, anyway, and it's the definition that makes the most sense to me). But even beyond that, it seems intuitively obvious to me that your brain's counterfactual dependencies are what make your brain, your brain. If you had a different set of dependencies, you would have to have different neuronal wirings and therefore a different brain.

Anyway, this whole business of computation and higher-level causal structure and counterfactual dependencies: that does seem to have the right kind of specialness to me to generate consciousness. It's hard for me to break the intuition down further than that, beyond saying that it's the if-then pattern that seems like the really important thing here. I just can't see what else it could be. And this view does have some nice features - if you wind up meeting apparently-conscious aliens, you don't have to look to see if they have neurons. You can just look to see if they have the right if-then pattern in their mind.

To answer your question about simulations not being the thing that they're simulating: I think the view of consciousness as a particular causal pattern kind of dissolves that question. If you think the only thing that matters in terms of creating consciousness is that there be a particular if-then causal structure (as I do), then in what sense are you "simulating" the causal structure when you implement it on a computer? It's still the same structure, still has the same dependencies. That seems just as real to me as what the brain does - you could just as easily say that neurons are "simulating" consciousness. Essentially machine functionalists think that causal structure is all there is in terms of consciousness, and under that view the line between something being a "simulation" versus being "real" kind of disappears.

Does that help you understand where I'm coming from? I'd be interested to hear where in that line of arguments/intuitions I lost you.

So, one reason I pointed you at orthonormal's sequence is that if you read all those posts they seem likely to trigger different intuitions for you.

I would also ask if you think that Aristotle - had he only been smarter - could have figured out his "unique type of physico-chemical causal (space-time) structure" from pure introspection. A negative answer would not automatically prove functionalism. We know of other limits on knowledge. But it does show that the thought experiment in which you are currently a simulation is at least as 'conceivable' as the thought experiment of a zombie without consciousness and perhaps even your scenarios. Furthermore, the mathematical examples of limits on self-knowledge actually point towards structure being independent of 'substrates'. That's how computer science started in the first place.

This is incorrect because the causal structure of a Turing machine simulating a human brain is very different from an actual human brain.

There are at least two causal structure levels in a computational system: the physical substrate level and the program level (and potentially more with multiple levels of simulation). A computational system is one that can organize it's energy flow (state transitions in the substrate) in a very particular way so as to realize/implement any computable causal structure at the program/simulation level.

The causal structure at the substrate level is literally factored out - it does not matter (beyond performance constraints). Universal computability is not a theory at this point - it is a proven hard true fact.

causal structure of a Turing machine simulating a human brain is very different from an actual human brain.

This statement contravenes universal computability, and is therefore false. A universal computer can instantiate any other causal structure. Remember: the causal structure at the substrate level is irrelevant due to the universality of computation. Causal structures can be embedded within other causal structures (multiple realizability).

A brain is just matter, and more specifically it is just an electromechanical biological computer. It is also just a conventional irreversible computer which dissipates energy along it's wires and junctions according to the same exact physical constraints that face modern electronic computers. It can be simulated because anything can be simulated!

Let's cut to the chase: are there any empirical predictions where your viewpoint disagrees with functionalism?

For example, I predict that within a decade or two, computers with about 10^14 ops will run human mind simulations, and these sims will pass any and all objective tests for human intelligence, self-awareness, consciousness, etc.

Furthermore, you won't be able to tell the difference between a human controlling a humanoid avatar in virtual reality and an AI controlling a humanoid avatar (imitating human control).

People will just accept that sims are conscious/self-aware for the exact same reasons that we reject solipsism.