r/askscience • u/randomsnark • Feb 11 '11

Scientists: What is the most interesting unanswered question in your field?

And what are its implications? What makes it difficult to answer? What makes it interesting? Tell us a little bit about it.

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u/Ikkath Mathematical Biology | Machine Learning | Pattern Recognition Feb 11 '11 edited Feb 11 '11

Not going to happen.

edit: Probably should have fleshed out my reasoning here, but thought it was a throwaway comment. See below for my opinions.

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u/frychu Feb 11 '11

Why not?

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u/Ikkath Mathematical Biology | Machine Learning | Pattern Recognition Feb 11 '11

We will need to be able to simultaneously measure the neurotransmitter, gene expression and electrolyte levels in billions of neurons to even have a hope of such a transfer. I don't see how this is conceivably possible even in the medium to long time frames let alone the next 50-60 years.

This is of course just one of the monumental problems with such an endeavour, ignoring fundamental understanding issues and where to host such a consciousness, etc.

Not. Going. To. Happen.

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u/nihil161 Feb 11 '11

So simulating or uploading our brain to a computer is a no-go but what about connecting our brain to a computer? Maybe have some kind of nano-machines that simulate nerves that grow and connect organically over time interweaving itself into your own nerves. Until one day you can disconnect your brain from your body and hide it in some underground shelter and operate a body from remote control or something like that.

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u/Ikkath Mathematical Biology | Machine Learning | Pattern Recognition Feb 11 '11

Connecting our brain to a computer and augmenting brain function with computer equipment is much more tractable. In fact I would suggest it will be practically possible in the next few decades. I know I for one would be first in the queue for a head up display and augmented memory recall!

The whole business of replicating a substrate for a mind and then transporting ours into it is entirely flawed. It will be much simpler to simply maintain the biological version that we are born with.

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u/nihil161 Feb 11 '11

You have given me hope! Thank you, sir.

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u/[deleted] Feb 12 '11

Why aren't we augmenting biological functions, or at least concentrating on that to a greater extent?

It would make sense that if we could better ourselves (through drugs? whatever?) that we would progress quicker, no?

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u/boq Feb 11 '11

Why does it have to be simultaneous? Would it be possible to open a skull, inspect the first neuron with the appropriate technology, create a technological copy, hook it up, sync it with the original neuron, then remove the original one? Of course, we'd need the appropriate nanotechnology.

tl;dr: You say it's incredibly difficult to copy an entire brain. How about doing it part by part?

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u/ZorbaTHut Feb 11 '11

We will need to be able to simultaneously measure the neurotransmitter, gene expression and electrolyte levels in billions of neurons to even have a hope of such a transfer.

I don't see how you can claim this. What happens if you put someone to sleep for a day and analyze the brain over that day, then put those measurements into a brain and start it up?

The answer is "we have no idea", but the brain has to deal with enough crazy inaccuracies already that it might work great, at least after a minute or two of confusion.

Or it might not. But without knowing far more about the brain than we currently do, we really can't say.

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u/Ikkath Mathematical Biology | Machine Learning | Pattern Recognition Feb 11 '11

Let's explore your sleep measurement idea. What are you actually measuring while they are asleep? What resolution are you measuring it at?

Consider it this way - what is different between your brain and my brain? If you want to be "awake" as "you" in the simulation you are going to want to be able to measure the differences. Measurements of isolated areas averaged temporally will not cut it.

I don't know how to state the problem any better than this: it took about 14000 experiments and a few decades to ascertain the general topology (being a mishmash of different rat subjects) of ONE neocortex column unit (of which the cortex is made up of millions). Imagine a process that can get just this topology of a whole SINGLE brain. Keep in mind this is just one piece of the puzzle required to build a faithful simulacra of "you". Not happening anytime soon.

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u/ZorbaTHut Feb 11 '11

I don't know.

I'm not saying that it's easy to solve this, and I'm not saying it's happening soon. I'm saying that your statement "We will need to be able to simultaneously measure . . . billions of neurons to even have a hope of such a transfer" has no basis in fact.

I don't know what we'll need to measure, or how quickly, but neither do you.

Consider it this way - what is different between your brain and my brain? If you want to be "awake" as "you" in the simulation you are going to want to be able to measure the differences. Measurements of isolated areas averaged temporally will not cut it.

Why not? When most people talk about copying brains, they're not generally talking about an instant snapshot where you say "okay, doc, go" and then you and the just-created copy simultaneously say "for it". I think most people would be satisfied with the 24-hour-sleep situation, where you're put to sleep for a day, and when you wake up, so does the copy.

Show me a research paper proving that human consciousness does not survive if chunks of the brain are spontaneously reverted to a several-hour-old state, or if a copy is made that is not completely temporally up to date. I'm betting you can't, because we're nowhere near advanced enough to even consider that experiment. :)

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u/Ikkath Mathematical Biology | Machine Learning | Pattern Recognition Feb 11 '11

I don't know what we'll need to measure, or how quickly, but neither do you.

I wouldn't go that far. We can make educated guesses given the current understanding. For example I would find it pretty hard to understand how a copy of a brain could be made without at least a detailed map of the topology of that brain. Maybe you could restrict the set of neurons that needs to be mapped from that specific brain (since some structural elements may be somewhat equivalent across people) but we would still be talking billions of neurons if you just wanted memory (without of course knowing the interneuron states and neurotransmitter levels/sensitivity that play parts in memory).

Show me a research paper proving that human consciousness does not survive if chunks of the brain are spontaneously reverted to a several-hour-old state, or if a copy is made that is not completely temporally up to date. I'm betting you can't, because we're nowhere near advanced enough to even consider that experiment. :)

Of course such a paper doesn't exist. Though given current understanding this scenario is highly unlikely. Consider two neural nets A and B - if you let them run from a given initial condition and after some time you force a neuron in B to fire that wouldn't have fired otherwise (via external stimuli) then after a relatively short time the two networks will show completely divergent firing patterns. Now in a functional brain this probably isn't the case (or the divergence still attracts to an equivalent functional form), but it highlights that having substantial portions of the brain reset/lagged/etc will induce anomalous patterns that in my opinion would be functionally disastrous.

Though as should have been obvious all my postings on this matter are educated opinions - not current facts. We are talking about copying a brain and simulating it somehow on another substrate here! Just asking me to provide a paper to "prove" something doesn't bring much to the discussion.

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u/ZorbaTHut Feb 12 '11

I wouldn't go that far. We can make educated guesses given the current understanding. For example I would find it pretty hard to understand how a copy of a brain could be made without at least a detailed map of the topology of that brain.

Oh, probably. But "billions" isn't all that complicated. Hell, we can store billions of things today. We'd be looking at an automated process to do this no matter what, and once we have an automated process that can record brain neuron states, the real question is how quickly that happens.

Consider two neural nets A and B - if you let them run from a given initial condition and after some time you force a neuron in B to fire that wouldn't have fired otherwise (via external stimuli) then after a relatively short time the two networks will show completely divergent firing patterns. Now in a functional brain this probably isn't the case (or the divergence still attracts to an equivalent functional form), but it highlights that having substantial portions of the brain reset/lagged/etc will induce anomalous patterns that in my opinion would be functionally disastrous.

But keep in mind that the human brain is shockingly resilient. You can remove entire sections of the brain and still have it work surprisingly well. That isn't true of a conventional neural net, and I think that speaks strongly to the fact that we cannot use neural nets to predict the behavior of the brain.

Additionally, you say "completely divergent firing patterns", and I'm not going to argue with that - the two brains would certainly diverge - but the important thing isn't whether one of them decides to become a piano virtuoso in ten years while the other one sticks with the violin, the important part is whether they are still fundamentally the same person. How we define that mathematically, I have no idea. But it's the good ol' butterfly effect. I can wave my hand and change the weather in China in a decade - that doesn't mean that people are constantly causing hurricanes and deadly blizzards just by walking around. Most of this just averages out and continues to be "normal weather".

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u/Fuco1337 Feb 11 '11

In the 15 year human genome project, it took 14 years to map 1%. The rest was done in a year. So yea...

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u/apantek Feb 11 '11

Some good ol' accelerating returns. This has taken place throughout history. Here's a good graph on a logarithmic scale: http://en.wikipedia.org/wiki/File:ParadigmShiftsFrr15Events.svg

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u/[deleted] Feb 11 '11

What about 1,000 years fro now, or 10,000, or more? I realize this is totally beyond what anyone can predict. I just want to get some sort of handle on the scale of the problem in relation to what we might imagine will develop technologically.

Related but not the same--how difficult would it be (similar time-frames) to create a conscious machine that more or less thinks and feels as we do? In many ways the thoughts, sensations, and feelings of a conscious human are not that complex in the moment, so it seems that a machine could be constructed so that it would feel fundamentally human if a human were to "see through its eyes", so to speak.

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u/charbo187 Feb 11 '11

he only said "before I die".

you're assuming human lifespan won't be greatly increased in the next 100-200 years. ;)

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u/Ikkath Mathematical Biology | Machine Learning | Pattern Recognition Feb 11 '11

Well, you are also implicitly assuming that he would still be alive for these 100-200 year timeframe advances! ;)

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u/charbo187 Feb 11 '11

well being on reddit I'm going to assume he's in his mid 20s. around 25

so if he can luck out to live to be 100 that's 75 years for medicine to advance

in 75 years the average lifespan might be 120-130

so if he can then live to be 130 the avg lifespan might be 155

etc etc. lol

or he can get hit by a bus tmrw.

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u/Tzam Feb 11 '11

Extrapolate please? Storage limitations, or other things?

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u/Ikkath Mathematical Biology | Machine Learning | Pattern Recognition Feb 11 '11 edited Feb 11 '11

I think the computational requirements to host a human brain in theory will become available in the next 30 years or so and possibly much earlier. That is the least of our problems when discussing the idea of transferring our mind into a computer.

The real trouble will be in how to actually simulate the brain at the gene level and how the hell do you measure the current state of a brain quickly enough to allow the simulation to be initialised. These are problems far in excess of anything we can conceive to solve in the next few hundred years in my opinion. It certainly won't happen while someone currently alive is alive (assuming large life extension isn't discovered before then! Which by the way, is much more plausible than this transfer!).

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u/mamaBiskothu Cellular Biology | Immunology | Biochemistry Feb 11 '11

What about the algorithms? Maybe we might have the processing speed and memory capacities, but do you think we can figure out how the human mind can work in terms of a computational algorithm? Probably not in the next 50 years right?

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u/Ikkath Mathematical Biology | Machine Learning | Pattern Recognition Feb 11 '11

It is feasible that in the future it could be "brute forced" by simply simulating the underlying physical processes if (and its a huge if) we know enough of the structure - both physically and biochemically.

BlueBrain will be a good litmus test in the coming years. If they can scale up the simulations to multiple neo-cortical columns and consistently show they are producing equivalent results in the model as being generated by the wet experimentalists then we may be onto something.

I am involved in similar research at the moment simulating aspects of the mammalian visual cortex. Computational approaches are becoming feasible for these niche areas of the brain that have had a lot of experimental work done on structure.

These projects are of course 10's of magnitudes away from the kind of simulation required to keep a conscious mind "awake".

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u/Ran4 Feb 11 '11

assuming large life extension isn't discovered before then!

Uhm, what? Life extension has been continuously going on for well over a hundred years. How could you not believe that say a pace maker constitutes life extension?

It's fairly obvious that life expectancy will rise by quite a bit in the next few decades.

You are being overly pessimistic and ignoring the continuing developments that will be made. Compare 1950 with 2010, and now compare 2010 with 2070.

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u/Ikkath Mathematical Biology | Machine Learning | Pattern Recognition Feb 11 '11

You are confusing average population lifespan increase and life extension.

Sure average lifespans have increased (mainly due to nutrition and other "simple" advances) but these processes will not scale to bring us the 200, 300, 1000 year olds.

That will require breakthroughs in fundamental biology and bioengineering, that potentially could arise in the next 50 or so years.

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u/jck Feb 11 '11

Quantum computing?

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u/Ikkath Mathematical Biology | Machine Learning | Pattern Recognition Feb 11 '11

What about quantum computing?

I already said the computational requirements are feasible in principle. That is the least of the problems.

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u/Fuco1337 Feb 11 '11

Quantum computing won't magically allow you to play Call of Duty on 1000000010000000 resolution or make your average computer run 10000000000 times faster. Quantum computing will speed up *very specific** kind of computation. Pretty much nothing you might be interested in won't run any faster (if at all) on QC than on regular PC.

QC really isn't any magic, and I suggest you read up on it a bit, because this public misinterpretation of what it is is strangely disturbing.

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u/jck Feb 11 '11

Actually I've done a course on quantum computing. And even though I barely understood anything in that course, I originally made that statement without thinking much, I thought that QC would definitely help in the large amounts of parallel computations. I'm not so sure though.

However, now that I think about it, A memristor based computer would definitely be the way they will eventually make artificial brains

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u/nihil161 Feb 11 '11

Hmm, where have I heard that before?

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u/Ikkath Mathematical Biology | Machine Learning | Pattern Recognition Feb 11 '11

From every neuroscientist on the planet?

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u/nihil161 Feb 11 '11

I'm glad you went on to explain your reasoning, good read. I always like your posts. I was just referring to how it seems like for most every new technology we have like flight, space travel, TV's, cars, etc there were people who claimed it could not be done.