LESSWRONG
LW

All of brainmaps's Comments + Replies

Shawn Mikula on Brain Preservation Protocols and Extensions

Neurons perform analog summation, so the space-time diagram or causal structure is stochastic/statistical rather than deterministic

Surely you realize that quibbling over the use of analog vs digital neural summation in my toy example does not address my main argument.

Neural analog computational systems can be simulated perfectly in a probabilistic sense

Anything can be simulated perfectly (and trivially) in a probabilistic sense.

There are no objective tests for consciousness. Of course you can re-define it in terms of self-awareness but this i

brainmaps10y30

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).

My statement does not contravene universal computability since I'm assuming a Turing machine can simulate a hu... (read more)

-3jacob_cannell10y

Well, if you assume that, then you are already most of the way to functionalism, but I suspect we may be talking about different types of simulations. Neurons perform analog summation, so the space-time diagram or causal structure is stochastic/statistical rather than deterministic (addition over real-number distributions rather than digital addition) . My use of the term 'simulation' encompasses probabilistic simulation which entails matching the statistical distribution over state transitions rather than deterministic simulation. Neural analog computational systems can be simulated perfectly in a probabilistic sense when you can recreate the exact conditional probability distributions that govern spike events. You can't necessarily predict the exact actions the brain will output (due to noise effects), but you can - in theory - predict actions from the exact correct distribution. At the limits of simulation we can predict exact samples from our multiverse distribution, rather than predict the exact future of our particular (unknowable) branch. Simulation of intelligent minds is fundamentally different than weather simulation - for the weather we are interested in the exact outcome in our specific universe. That would be comparable to simulating the exact thoughts of a particular human mind in some situation - which in general is computationally intractable (and unimportant for AI). Science is concerned with objective reality. A definition of consciousness which precludes objective testing is outside the realm of scientific inquiry at best, and pseudo-science at worse. In common usage the term consciousness refers to objective reality. Sentences of the form " I was conscious of X", or "Y rendered Bob unconscious", or "Perhaps at a subconscious level" all suggest a common meaning involving objectively verifiable computations. We know that consciousness is the particular mental state arising from various computations coordinated across some hundreds of major br

Shawn Mikula on Brain Preservation Protocols and Extensions

brainmaps10y00

Thank you for the thoughtful reply.

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.

Aren't neurons special? At the very... (read more)

Shawn Mikula on Brain Preservation Protocols and Extensions

brainmaps10y00

The algorithmic computations can be instantiated in many different causal structures but only some will

Any sentence of this form is provably false, due to the universality of computation and multiple realizability.

This is incorrect because the causal structure of a Turing machine simulating a human brain is very different from an actual human brain. Of course, you can redefine causality in terms of "simulation causality" but the underlying causal structure of the respective systems will be very different.

Yes it is - causal structure is ju

... (read more)

2jacob_cannell10y

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. 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.

Shawn Mikula on Brain Preservation Protocols and Extensions

brainmaps10y00

No, but as others pointed out, an animated GIF is not a simulation of the thing it represents.

The animated GIF, as I originally described it, is an "imitation of the operation of a real-world process or system over time", which is the verbatim definition (from Wikipedia) of a simulation. Counterfactual dependencies are not needed for imitation.

Just to be clear, when we are talking of simulations of a computational system, we mean something that computes the same input to output mapping of the system that is simulated, the same mathematical

... (read more)

0hairyfigment10y

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.

1ahbwramc10y

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

Shawn Mikula on Brain Preservation Protocols and Extensions

brainmaps10y10

thanks. I'm not sure if you were pointing me in that direction for a specific reason but found commentator pjeby's explanation for the ineffability of qualia insightful.

Shawn Mikula on Brain Preservation Protocols and Extensions

brainmaps10y10

It's unclear why counterfactual dependencies would be necessary for machine functionalism, but ok, let's include them in the GIF example. Take the first GIF as the initial condition and let the (binary) state of pixel, Xi, at time step, t, take the form, f(i,X1(t-1),X2(t-1),...Xn(t-1)). Does this make it any more plausible that the animated GIF has human consciousness? If you think the GIF has human consciousness, then what is the significance of the fact that the system of equations is generally underdetermined? Personally, it's not plausible that the GIF... (read more)

0DanielLC10y

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?

Shawn Mikula on Brain Preservation Protocols and Extensions

brainmaps10y50

Thanks for the replies. I will try to answer and expand on the points raised. There are a number of reductio ad absurdums that dissuade me from machine functionalism, including Ned Block's China brain and also the idea that a Turing machine running a human brain simulation would possess human consciousness. Let me try to take the absurdity to the next level with the following example:

Does an animated GIF possess human consciousness?

Imagine we record the activity of every neuron in a human brain at every millisecond; at each millisecond, we record whether ... (read more)

-1jacob_cannell10y

A GIF is just an image, it is not a simulation. The appeal of the GIF thought experiment relies on a misunderstanding of computation and simulation. Take a photo of a dolphin swimming - can the photo swim? Of course not. But imagine scanning a perfect nanometer resolution 3D image of a dolphin and using that data to construct an artificial robotic dolphin. Can the robot dolphin swim? Obviously - yes, if constructed correctly. Can the 3D image swim by itself ? No. Now replace dolphin with brain, and swim with think. Thinking is a computational process, and computation is physical, like swimming - it involves energy, mass, and state transitions. Physics is computational. Yes it is - causal structure is just computational structure, there is no difference. Any sentence of this form is provably false, due to the universality of computation and multiple realizability. Any algorithmic computation can be instantiated in any universal computer and is always the same.

3V_V10y

Thanks for your answers. No, but as others pointed out, an animated GIF is not a simulation of the thing it represents. Just to be clear, when we are talking of simulations of a computational system, we mean something that computes the same input to output mapping of the system that is simulated, the same mathematical function (or, more precisely the same posterior, if the system is stochastic). An animated GIF doesn't respond to inputs, therefore it doesn't compute the same function that the brain computes. Think of playing an old console video game on an emulator vs watching a video recorded from the console screen of somebody playing that game. Clearly the emulator and the video are very different objects: you can legitimately say that the emulator is simulating the game, furthermore you can say that the emulator is actually running the game: "Being a video game" is a property of certain patterns of input-output mappings, and this property is invariant (up to a performance overhead) under simulation, it is independent on the physical substrate. on the other hand, the video record of somebody playing a game can't be said to be a game, or even the simulation of a game. Well-coded chatbots don't come any close to simulating the linguistic behavior of humans. There are claims now and then that some chatbot passed the Turing test, but if you look past the hype, all these claims are fundamentally false. Here it is Scott Aaronson's take on the last of these claims. Seriously, if we really had computer programs passing the Turing test, we would probably also have computer programs working as engineers or lawyers. I'm asking how you understand the term at operational level right now. Let me introduce you Foo. Foo may be a human, an animal, a plant, a non-living object, etc. It may be an artifact, or a natural-occurring object, or a combination of both. It may be in a normal state for its kind of objects or an abnormal state (e.g. in coma, out of fuel, out of batte

1hairyfigment10y

You may want to look at the short sequence that starts here.

4ahbwramc10y

I think we might be working with different definitions of the term "causal structure"? The way I see it, what matters for whether or not two things have the same causal structure is counterfactual dependency - if neuron A hadn't have fired, then neuron B would have fired. And we all agree that in a perfect simulation this kind of dependency is preserved. So yes, neurons and transistors have different lower-level causal behaviour, but I wouldn't call that a different causal structure as long as they both implement a system that behaves the same under different counterfactuals. That's what I think is wrong with your GIF example, btw - there's no counterfactual dependency whatsoever. If I delete a particular pixel from one frame of the animation, the next frame wouldn't change at all. Of course there was the proper dependency when the GIF was originally computed, and I would certainly say that that computation, however it was implemented, was conscious. But not the GIF itself, no. Anyway, beyond that, we're obviously working from very different intuitions, because I don't see the China Brain or Turing machine examples as reductio's at all - I'm perfectly willing to accept that those entities would be conscious.

Shawn Mikula on Brain Preservation Protocols and Extensions

brainmaps10y80

Shawn Mikula here. Allow me to clear up the confusion that appears to have been caused by being quoted out of context. I clearly state in the part of my answer preceding the quoted text the following:

"2) assuming you can run accurate simulations of the mind based on these structural maps, are they conscious?".

So this is not a question of misunderstanding universal computation and whether a computer simulation can mimic, for practical purposes, the computations of the brain. I am already assuming the computer simulation is mimicking the brain's... (read more)

2Kyre10y

Thanks for replying ! Sorry if the bit I quoted was too short and over-simplified. That does clarify things, although I'm having difficulty understanding what you mean by the phrase "causal structure". I take it you do not mean the physical shape or substance, because you say that a different computer architecture could potentially have the right causal structure. And I take it you don't mean the cause and effect relationship between parts of the computer that are representing parts of the brain, because I think that can be put into one-to-one correspondence with the cause and effect relationship of the things being represented. For example, If neuron N1 causes changes to neurons N2, N3 and N4; and I have a simulated S1 causing changes to simulated S2, S3 and S4, then that simulated cause and effect happens by honest-to-god physical cause and effect: voltage levels in the memory gates representing S1 propagate through the architecture to the gates representing S2, S3, S4 causing them to change. So consciousness would have to then be something that flesh brains and "correctly causally structured" computer hardware have in common, but which is not shared by a simulation of either of those things running on a conventional computer ?

1V_V10y

The natural objection is, why would the physical substrate matter? Let's assume you replace somebody's brain with a Von Neumann computer running a simulation of that person's brain. You get something that behaves like a conscious person, and even claims to be conscious person if asked. Would you say that this thing is not conscious? If you think it is not conscious, then what does "conscious" actually mean in epistemic terms? If I tell you that X is conscious, how do you update your posterior beliefs on the outcomes of future observations about X?

1jacob_cannell10y

Shawn - firstly, congratulations on your BROPA research and publication; it is likely to have high future impact. Universal computation necessarily implies/requires multiple realizability of causal systems and thus functionalism. Part of the confusion stems from the use of the term 'consciousness' and all of it's associated baggage. So let us taboo the word and use self-awareness instead. Self-awareness conveys most of the same meaning, but without the connotations (just as we may prefer the term 'mind' over 'soul'). Self-awareness is a specific key information processing capability that some intelligent systems/agents possess. Some animals (dolphins, monkeys, humans, etc) demonstrate general self-awareness through their ability to recognize themselves in mirrors. Self-recognition in a mirror test requires a specific ability to construct a predictive model of one's self as an object embedded in the world. The other day while on a walk I came upon a songbird that was repeatedly attacking a car (with a short hop ramming maneuver). I was puzzled until I realized that the bird was specifically attacking the side view mirror. I watched it for about 10 minutes and it just did the same attack over and over again. The next day I saw it attacking a different car in about the same location. Humans possess a more advanced form of self-awareness related to our ability to use language to communicate. Natural linguistic communication is very complex - it requires a sophisticated capability to model not only one's self - but other self-aware agents as well, along with those other agent's models of oneself and other agents, and so on recursively. Self-awareness isn't a binary concept - obviously it comes in many varieties and flavours, such that individual humans are not self-aware in exactly the same way. Nonetheless, these differences are tiny in comparison to those that separate typical human self-awareness from feline SA or the rudimentary SA of current artificial agents.