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Comment by jcoffland | Hacker News Reader

> If we knew enough, and had the technology, we could exactly copy its structure and emulate its behavior with electronic components, just like we can simulate very basic neural anatomy today.

Being able to simulate a brain with electronics, if it is possible, is not enough. You have to simulate it without a large increase in the space or time requirements. If there are 100B neurons in the human brain but it takes 100B^2 transistors to simulate it or the simulation takes polynomial time to complete a task that the human brain requires only linear time for, it's a bust.

Just because we can easily imagine it does not make it easily achievable or even possible.

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> Just because we can easily imagine it does not make it easily achievable or even possible.

It is without question possible, because we exist. It is also possible to do it quickly, because again, we exist. The only thing that is unclear is:

1. How hard it is to do artificially.

2. How far from optimum the human mind is, and how complex it is to improve upon it.

But is it possible with the technology we have discovered so far?

> It is without question possible, because we exist. It is also possible to do it quickly, because again, we exist.

It's apparent that we don't know everything.

> But is it possible with the technology we have discovered so far?

I think I feel comfortable saying that it is possible to do with the technology we have. Because 'intelligence' is almost certainly some form of computable function, which means that a turing complete computer can compute it.

It is of course possible that there exists some special function outside of turing completeness and intelligence is one of those, but we don't know of anything like that, so the best bet to make is that that is not the case.

> It's apparent that we don't know everything.

No, but we do know some things. And thus far we've been able to at least begin to design systems capable of performing any well-defined task. We don't have any reason, at the moment, to believe synthesizing an intelligence is an especially difficult problem, relative to say, lots of other open problems in science and technology.

Turing computable does not mean it can be computed in a reasonable amount of time with a classical computer. There are many things that are known to be computable that we will never be able to compute on a classical or even quantum computer. We do not know that the brain is not quantum equivalent or better.

We also have no reason to believe that it is. Sure, it's possible that we'll happen to discover an algorithm less efficient at computing the 'intelligence' function than our brains. We may also discover one more efficient. We can't really say much at all about it at this time.

Agreed. I think we are still a long way off but some essential discovery could be just around the corner.

Ironically, given the articles criticism of the simulation argument, there is an 'escape hatch' with respect of the ability of simulating a human mind in the form of the simulation argument: it is possible that human brains in our universe is just the tip of the iceberg and relies on a massive amount of computation 'outside' of the main simulation that is impossible to do faster 'in universe'.

Of course we have absolutely nothing to indicate that would be the case, but we also don't understand the brain well enough yet.

That's a really interesting thought. Essentially, the technical analogy of what a 'soul' could be.

I've read some good SF stories with that premise. Of course, it has nothing to do with reality.

Maybe it doesn't. But the only way we have of knowing that is to construct an AGI and demonstrate that it can be done in roughly the same volume and power consumption as a human brain.

Yes, we could in theory find when we try to simulate a brain that nothing we do produces anything working. Imagine a simulation where a human being conceived or born or whatever, triggering the instantiation of a "conduit" between a simulation of the universe and a simulation of a mind, where the in-universe brain is "just" a glorified IO device.

I think it'd be highly improbable, but looking at the crude simulations we do of computers etc. today, it certainly is likely that simulations would use "dirty tricks" to get more out of the available computational resources, and finding artefacts of such dirty tricks or shortcuts could at least in theory be possible. Of course, the absence of such artefacts unfortunately proves nothing, so the whole thing does have a bit of a "how many angels can dance on pin" feel to it. But it's fun to think about the possible implications.

Personally I especially like to bring it up if people try to discuss religion with me.

> How far from optimum the human mind is, and how complex it is to improve upon it.

Nature is pretty good at optimization. We can often build devices that out perform animals on certain characteristics, but that's because we've limited the scope of what they do and we aren't concerned with the energy requirements. We also know that, as interesting as our brains are and as powerful as they are at certain kinds of problems, they aren't the best at all of them. For instance, chimps appear to have a significantly better short term working memory. It is possible that we are already close to optimum for the kind of intelligence we are interested in. I suspect that if we manage to significantly improve upon it, it will be because we don't have to concern ourselves with the energy requirements.

>Nature is pretty good at optimization.

Only if there is a benefit to doing so. If it was simply a case of "nature can optimize really well" then we would expect to find many species at or near the limit of intelligence, not just one. Other species did not have the evolutionary pressure to cause as high of intelligence to be selected for. It is very reasonable to think that we also did not have the evolutionary pressure necessary to cause us to have even higher intelligence than we do.

Not really disagreeing with your, but a couple of points:

1. Signal propagation between organic neurons is slow - about 120 m/s. An electrical simulation may have problems with density, but this might be offset by the much greater speed of electrical current.

2. Neurons are electrochemically complex and afaik we still don't know how to model their behaviour with high fidelity.

Why would it scale with the square? A brain is a physical system, and computers can simulate physics in a way that scales. In principle it might have to be a quantum computer, but most people who've looked into that are very skeptical.

A better argument is that neurons do complicated things. But they also satisfy many inessential requirements in having to be built by evolved machinery and to stay alive; a designed system with more advanced technology than ours could do at least as well at thinking while dropping the inessential needs. So that's certainly possible. This leaves "not easily achievable". It only has to be accessible enough for someone; I-can't-imagine-how isn't a strong argument.

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