Identity, a neurobiological perspective

Originally posted on Scientia Salon:

320x240by William Skaggs

The philosophical problem of identity is epitomized by the paradox known as the “Ship of Theseus.” Suppose a ship is rebuilt by removing one plank at a time, and replacing it with a new plank of the same shape and material. Is it still the same ship? Most people would say so. But suppose all the planks that were removed are brought together and used to construct a new ship of identical form. Wouldn’t it be more appropriate to say that is the same ship as the original, and the one with new planks is a duplicate? There is no easy answer. Every possible reply seems to lead into a morass.

The Ship of Theseus and several related paradoxes have been tangling philosophers in knots for thousands of years, dating back to the ancient Greeks and continuing with Locke, Hume, Kant, etc. It is easy to get a…

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Reaching the stars will require serious out-of-the-box thinking

Sten Odenwald, an astronomer with the National Institute of Aerospace, has an article up at HuffPost that many will find disheartening: The Dismal Future of Interstellar Travel | Dr. Sten Odenwald.

I have been an avid science fiction reader all my life, but as an astronomer for over half my life, the essential paradox of my fantasy world can no longer be maintained. Basically, science tells us that traveling fast enough to make interstellar travel possible requires more money than society will ever be able to invest in the attempt.

Einstein’s theory of special relativity works phenomenally well, with no obvious errors in the domain relevant to space travel. His more comprehensive theory of general relativity also works exceptionally well and offers no workable opportunity to “warp” space in a way that can be technologically applied to space travel without killing the traveler or incinerating the universe. Interstellar travel will be constrained by the reality of special relativity and general relativity, and there is no monkeying with Mother Nature to make science fiction a reality.

…Andreas Hein, an engineer with the Icarus Interstellar Project, developed a rigorous method for forecasting the economics of interstellar travel, only to find that most economically plausible scenarios for a “Daedalus-type” mission would cost upwards of $174 trillion and require nearly 40 years of development and 0.4 percent of the world GDP. This would be for an unmanned, 50-year journey to Barnard’s Star using “fusion drive” technology. It consists of 50,000 tons of fuel and 500 tons of scientific equipment. Top speed: 12 percent of the speed of light.

There’s a fair amount of chest thumping in the comments decrying Odenwald’s pessimism, comparing him to people in history who claimed we’d never fly, exceed the sound barrier, etc.  Most of these commenters don’t understand how fundamentally different the challenges of interstellar travel really are.  Many of the historical thresholds they reference were engineering challenges, but there was never any serious doubt among scientists that they were fundamentally possible.

The speed of light limit is based on Einstein’s theory of special relativity.  It basically says that nothing with mass can reach the speed of light, much less exceed it.  The reason is that as your speed increases, so does your mass, albeit infinitesimally at normal speeds.  As you get closer to the speed of light, more and more of the energy you’re using to increase your speed actually goes into increasing your mass.  At 99.9999% of the speed of light, almost all of the energy goes to increasing mass.  To actually reach the speed of light would require an infinite amount of energy.  All the energy in the observable universe wouldn’t be enough to push a single proton up to the speed of light.

To be clear, nothing in nature has been observed to travel faster than light.  Lots of people have tried to find loopholes in the laws of physics.  They have speculated about things like wormholes, Alcubierre drives, quantum entanglement communication, and many other notions.  But these are all profoundly speculative concepts with zero evidence and major theoretical problems.  Many people know about some of the proposed solutions to these problems, but the solutions themselves are also profoundly speculative.  The majority of physicists are far from optimistic that there is any feasible way to travel, or even communicate, faster than light.

Even achieving a reasonable percentage of the speed of light is going to require major breakthroughs in physics if we want to send biological humans.  It’s trivial to espouse confidence that those breakthroughs will come, but counting on them is simply engaging in fantasy rather than scientific speculation.

Paul Gilster at Centauri Dreams, a blog I enthusiastically recommend for anyone interested in interstellar travel, has provided a couple of much more intelligent responses, here and here.  Gilster’s best argument against the economics issue that Odenwald raises is to point out how much of a difference centuries of economic growth might make, which I think is an excellent point.  But it only gets us to robotic missions, with manned missions being orders of magnitude more complicated.  And although his attitude is far more optimistic, his actual final conclusions really aren’t that different from Odenwald’s.

So, can humanity make it to the stars?  I think the answer is yes, but it’s going to require profound out-of-the-box thinking.  Forget Star Wars or Star Trek type universes unless you just want to fantasize.  We need to look at possibilities actually allowed by the laws of physics.  No one alive today really knows what interstellar exploration will look like.  But here is plausible speculation that doesn’t violate the laws of physics and recognizes that economic limitations would be important.

  1. Biological humans will likely never go to the stars, or if they do, it will be as symbolic vanity projects of a society orders of magnitude richer than we are today, and they will be going places pioneered long before by robots.
  2. Interstellar probes will likely be small, possibly microscopic, in order to economically be accelerated to a significant percentage of the speed of light.  Even launching these small probes will be staggeringly expensive, but there will only need to be one per destination.  (Or possibly two in case one malfunctions.)
  3. Once at a destination, the probe may be programmed to find resources (asteroids, etc) and bootstrap an infrastructure in order to communicate with home, to create local probes to explore the destination solar system, and possibly to create daughter probes to be sent on to farther stars.
  4. Once a communication link is established with home, information on the destination can be transmitted back.  Depending on the initial communications, new AIs might be transmitted to the destination to enhance the exploration.
  5. As speculated by Odenwald, biological humans will be able to experience the remote locations in virtual reality built using the information transmitted back.
  6. Is there any hope of humans ever routinely going to the stars in person?  Well, that depends on what we mean by “in person”, and our attitude toward the possibility of mind uploading, the plausibility some of us have been debating on another thread.  In the absence of that, it’s hard to see humans having much of a presence in other solar systems.

Learning to work in the universe we have, rather than the one we wished we had, isn’t always easy.  But once you get used to it, the possibilities are exciting.  Odenwald talked about how much more democratic the experience of these locations would be with all of us essentially doing it in virtual, rather than a select few elite explorers.  There’s a lot to like in that vision.

The future will be strange.  No doubt it will be stranger than we can imagine.  I’m convinced interstellar exploration can happen, but it will likely require us giving up preconceived notions of how we wish it could work.

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Maybe we’ve found Neanderthals, and they are us.

The intermixing of modern humans and Neanderthals is back in the news: BBC News – DNA yields secrets of human pioneer.

DNA analysis of a 45,000-year-old human has helped scientists pinpoint when our ancestors interbred with Neanderthals.

The genome sequence from a thigh bone found in Siberia shows the first episode of mixing occurred between 50,000 and 60,000 years ago.

The male hunter is one of the earliest modern humans discovered in Eurasia.

The study in Nature journal also supports the finding that our species emerged from Africa some 60,000 years ago, before spreading around the world.

A year ago, I was pretty convinced that we, modern humans, were pretty much responsible for the extinction of the Neanderthals.  Various theories about climate change causing it didn’t seem compelling, since the Neanderthals had been around for hundreds of thousands of years, no doubt weathering many climate variations, but had disappeared right around the time modern humans encroached on their territory.

But the findings in recent years that all non-ethnic Africans have 2-4% Neanderthal DNA, has raised another interesting possibility.  (I wish I could find the article of the anthropologist who speculated about it, but I can’t, so you’ll have to read my amateur snippet.)

It appears that the population of Neanderthals was always low, a few tens of thousands across all of what is now Europe.  When modern humans started encroaching on them, those modern populations were orders of magnitude larger.  Maybe we didn’t eradicate Neanderthals or out compete them for resources (at least not completely).

Maybe we intermarried with and assimilated them.  It might be that Neanderthals didn’t so much go extinct as meld into the population of modern humans.  As someone who is 3% DNA (at least according to 23andMe), I find this idea intriguing.

Given the long history of us regarding the Neanderthals as some kind of ape-like sub-human, there may be resistance to this idea.  But the more I read and think about it, the more it seems like that’s where the evidence is pointing.

Maybe we’ve found Neanderthals and they are us.

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Massimo Pigliucci’s pessimistic view of mind uploading


Massimo Pigliucci wrote a paper on his skepticism of the possibility of mind uploading, the idea that our minds are information which it might be possible someday to copy into a computer virtual reality system or some other type of technology.  His paper appears to be one chapter in a broader book, ‘Intelligence Unbound: The Future of Uploaded and Machine Minds‘, which I think I will have to read.

Interestingly, Massimo’s paper is in response to a paper by David Chalmers which apparently supports the idea of MU (mind uploading).  I didn’t realize that Chalmers was open to something like that.  Usually I think of Chalmers as the philosopher hopelessly preoccupied with the mystery of consciousness, but it looks like he doesn’t let his fascination with that mystery preclude him from considering possibilities like MU.  This is causing me to reassess my views of him and wonder if I should be reading more of his material.

In his paper, I think Massimo makes some important cautionary points, but I think his conclusions from these points are unwarranted and over confident.  Unfortunately, the paper at the link is a scanned PDF, so I can’t paste snippets and respond to them,  so you’re going to get my own quick summation of each point.  But you shouldn’t take my word on these; his paper deserves to be read in full.

Massimo’s assertions are in bold, with my responses following.

The brain is not a digital computer.

Yep.  There are some advocates of MU who do seem to think that the brain is a digital computer, but I think anyone who has done any serious reading about the brain knows that isn’t true.  The brain appears to be a massively parallel loose cluster of analog processors.  Instead of transistors with discrete states, it uses synapses with smoothly varying strengths.

However, the brain takes in inputs from the senses, processes and stores information, and produces outputs in the form of movement.  If we built a device that did that, regardless of its architecture, we would almost certainly call it a computer.

MU depends on the computational theory of mind, which is flawed because “we now know a number of problems” which can’t be computed.

All indications are that the brain is a physical system that works in this universe.  If there are problems that modern computers can’t process, but that the brain can, that’s a flaw with modern computer architecture.  But it’s a major leap from that observation to saying that no technology could ever solve it.

If Massimo means that there are problems that could never be computed with any machine architecture ever, then he’s effectively saying that the human mind has a non-physical aspect outside of this universe, which I doubt is an assertion he wants to make.

A simulated mind is not the same as a functional mind.  Simulated photosynthesis doesn’t produce sugar, no matter how closely it models the actual physical process.  

Simulated photosynthesis produces simulated sugar.  A human mind is evolved to produce bodily movement.  A simulated mind would produce simulated movement, which might be quite satisfactory in a simulated environment.  But if the hardware running the simulated mind were connected to the right machinery, it could produce actual movements, turning the “simulation” into an arguably functional mind.

Would a simulated mind produce real consciousness?  (Whatever “real consciousness” is.)  It depends on how far down into the mechanisms a simulation goes, and at what layer in those mechanisms that consciousness actually resides.  If consciousness resides in the quantum layer, then it’s hard to see a simulation ever capturing it.  If it resides in the organization of neural and synaptic circuits, then I think it’s entirely doable, someday.

Human consciousness may be strongly dependent on its biological substrate.  In other words, human consciousness may require human biology.  Thinking otherwise is dualism, and dualism “has no place in modern philosophy of mind”.

This is entirely possible, although I think Massimo’s stand on this is filled with far too much certitude.  But even if it is possible, that doesn’t mean that human technology may not be able to someday duplicate that biological substrate.  It may be centuries in the future, but saying it will never happen strikes me as remarkably pessimistic about what human ingenuity might eventually be able to do.

Personally, I think a human consciousness uploaded into a silicon (or whatever) substrate will be unavoidably different.  The question is, would it be so different that friends and family wouldn’t recognize their loved one?  Of course, if the upload was not destructive, so that the original person was still around, the differences might be more noticeable.

I think the dualism assertion is, frankly, silly.  There’s no requirement for Cartesian “ghost in the machine” dualism.  The only type of dualism that would be required is the software/hardware dualism you accept by running Windows, Mac OS X, Linux, or whatever, on the device you’re using to read this.

Massimo feels it is self evident that Captain Kirk dies every time he steps into the Star Trek transporter.  Since transporting is effectively a type of MU, this means no one should want to be uploaded, at least not if its destructive.  Destructive uploading is hi-tech suicide.

I have to admit that I wouldn’t be eager to submit to a destructive (i.e. fatal) type of uploading.

But suppose I’m on my death bed.  Regardless of what I do, my current physical manifestation is about to end.  If I don’t upload, my pattern will disappear from the universe.  Uploading might produce an imperfect copy, but something of me would continue after I was gone, something far more intimate than my work or even my children.  That version of me would consider itself to be me.  If that’s all I had left, I think I’d take it.

It’s worth noting that, due to the body’s never ending repair and waste removal processes, the physical me that exists today isn’t the physical me from ten years ago.  Every atom in my brain has been replaced over those years.  My current mind is a very imperfect copy of that me from ten years ago.  Actually, it’s an imperfect copy of me from yesterday.  Yet, I’m never really tempted to wonder if tomorrow’s me will be the real me.

Again, I think Massimo raises a number of important cautionary points.  It might turn out that MU is impossible.  For example, despite all indications, we might discover that something like Cartesian dualism actually is reality.  Or human consciousness might be so fragile and so tightly tuned to the body it arose in that any attempt to copy it would render it non-functional.  Or it might reside in quantum layers of reality that we may never understand.  But I think these possibilities are unlikely.

My own prediction is that engineers will eventually produce something that resembles MU, that the uploaded minds will be different than the biological ones, that some people will be horrified by those differences, but that most will eventually learn to live with them, and simply come to see uploading as one of existence’s transitions.

It might be several centuries before this happens.  Even singularity enthusiasts only see it happening in the near future with the help of super-intelligent AIs.  But for many people, MU that is physically possible, but not achievable in our lifetimes, is the worst scenario, because it means that we might be among the last generations to disappear from the universe.  For these people, far better to conclude that it will never be possible.

I can understand this impulse.  But if it has any hope at all of being doable within any of our lifetimes, it’s unlikely to be accomplished by those who have already decided it is impossible.

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Philosophy Tech Support

(Click through for the rest, and for a caption explaining the philosophy referenced.)

via Philosophy Tech Support – Existential Comics.

Does philosophy have a responsibility to be relevant to real world problems?  This is a question often asked of science.  I think the answer is complicated, because we never know where a real world solution might come from.  Most of philosophy is a waste, but the problem is that there is no agreement on which part is useful and which is a waste, and you can never know when something that initially appears utterly irrelevant to the real world won’t turn out to have profound consequences.

That said, I’ve noticed a pattern in recent years with publications about scientific studies having a short blurb added explaining what its possible real world benefits might eventually be.  Should philosophy contemplate doing something similar?

Many might argue that no one expects mathematical proofs to have this kind of real world application, and they’d be right.  Of course, I doubt anyone would expect an abstract logical proof to have one either.  It’s only when  someone is attempting to apply math and logic to entities in the world where pragmatic applicability starts to become expected.

Personally, I think that both philosophy and science should be free to explore areas that might not have real world applicability, on the promise that many of those pursuits will stumble on pragmatic solutions.  But I can understand the other side of this argument given never ending budget pressures.

What do you think?

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Charlie Stross discusses life lessons at 50

Charlie Stross just turned 50 and put up a post discussing his major life lessons, things he wished he could tell his 15 year old self, which briefly are:

  1. Don’t die.  (Try not to fail at this one as long as you can.)
  2. Idiots abound.  (And recognize that correcting them is usually not your problem.)
  3. Follow the Golden Rule.  (He prefers the negative Confucian version: “do not do unto others that which would be repugnant were it done unto you”)
    1. Charlies does have some caveats for self defense and what-not.

Check out his post for the details.

I’m not quite 50 yet (I just turned 48 a few weeks ago), but I found Charlie’s list to be reasonable, although I think trying to distill all of life’s lessons to a short list is violating Einstein’s rule that things should be as simple as possible, but no simpler.  Reality is complicated, and many people are too impatient with that complexity.

Maybe that’s why at least three additional important life lessons quickly came to mind:

  1. Conventional wisdom is often wrong.  (Strikingly, this appears to include conventional wisdom among those familiar with this lesson.)
    1. Yes, I know many might see this as a detail of 2, but in my experience many smart people buy into the conventional wisdom.
  2. Most people are more concerned about your evaluation of them than they are about their evaluation of you.  This is usually true even if they are in the more powerful position.
  3. Cherish your real friends, and don’t make enemies when you don’t have to.

There are lots of others, but in the vein of prioritizing what I wish I could tell my 15 year old self, these are big ones.

What would your additions be?

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A Layperson’s guide to basic brain structure!

Originally posted on gwizlearning:

Following on from last week I thought it would be useful to start with a basic look at the “geography” of the brain and what is currently thought of as an overview of function.

I include here an image I drew so must first apologise if it is not completely in proportion… Do check out other images!

Brain lobes with label

The view shown here shows the frontal, parietal, occipital and temporal lobes. It also shows the cerebellum (more on this in later blogs).

You probably already know that the brain has two hemispheres, left and right. The lobes are sub-divisions of the lobes and appear in both hemispheres

The primary responsibility of the occipital lobe is vision. Damage to this lobe leads to blindness in part of the visual field.

The parietal lobe deals with body sensations while the temporal lobe contributes to hearing and to complex aspects of vision.

The frontal…

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