## Red meat and error correction

“The question whether machines can think as relevant as the question whether submarines can swim.” — Edsger W. Dijkstra

— nomnomnom

I love cooking, and eating, but for the carnivores among us its always depressing to hear how many years of our lives are being shaved off by our red-meat-eating habits. The herbivores are probably ecstatic every time the BBC news brings it up.  Myself, being a guilt-ridden meat eater, like a smoker who can never quit, thinks we probably deserve all the bad karma.  However, until guilt-free and life-enhancing test-tube-meat reaches a palatable stage, or our future generations are sucking mush through a straw into their chinless and toothless gobs, I will probably keep up my bad habits.  Another guilt-inducing fact that is often pointed out to me (and why me, I don’t know; perhaps my guilt is written plainly on my sleeve for Buddhists to pick at) is how inefficient an energy source meat is; it takes so-and-so many fields to feed-so-and-so many cows to feed so very few lucky meat eaters.  The ultimate limit of this logic of course is the fact that any bio-mass is extremely inefficient (both as an edible fuel source and as an renewable energy fuel source).  To my mind the only solution to this inexorable logic is to cast-off our fleshly shackles and embrace a totally digital life powered by the most efficient fuel one can imagine.  But what is the most efficient fuel? It is Max Tegmark.

— nom nom …nom?

Before explaining why Professor Tegmark is so efficient, lets discuss our brains a little.  Our biological brains consume upto an amazing 20% of our energy intake.  A substantial portion of this is spent opening and closing redundant ion channels on neurons, a kind of biological error correction needed because these channels are easily thermally or mechanically activated.  It is thought that primates get some of their IQ advantage from having small, more closely packed neurons (evidence mostly consists of our lack of Cetecean overlords), but there is only so far this scaling can go; neurons need a minimal number of ion channels (for the error-correction redundancy) which ultimately limits their miniaturization.  The ion channels could be made more reliable, so that there is a lower rate of thermal activation, but with an increased energy cost for those activations that we actually want. All of these are common problems for anyone working in information science, or anyone who has opened up a desktop computer.  Specialized processing and parralization, via multi-core CPUs and GPUs, is becoming more and more necessary as we reach the limits of transistor miniaturization.  But the communication overhead also imposes a limit on the usefulness of such compartmentalization.  How do the two technologies compare?  The human brain is estimated at 100 billion neurons, while the record CPU transistor count is 2.5 billion transistors, in Intel’s 10-core Xeon Westmere-EX.

—  Can a 10-core Xeon processor enjoy a good steak?

Probably this is not a meaningful comparison, but it seems with human brains we have already reached the limit of a biological Moore’s law.  So perhaps the only way forward, if we are going to improve cranially as a species (and be ultimately more fuel efficient) is a nice digital life. Imagining that we finally upload our brains to our Pentiums, or create the AI equivalent, how serious will our energy concerns be? Perhaps we will all be happy to live in virtual matrix-style World of Warcraft simulations. In this case our energy needs can be minimized drastically.  First of all energy for actual processing can be almost completely eliminated.  We can simply reduce the clock rate of our virtual noggins, assuming we no longer care about day to day life of the outside world, and of course our subjective experience will not be affected.  Thus minimal solar power or similar alternatives seems sufficient.  Still, what about physical degradation of our hardware and environment?  It is a great irony that it seems we can never completely escape our physical incarnation.  Similarly, if we do want to interact with our environment via robot bodies, real time, then our energy costs sky rocket.

— this is not a photo of Greg Egan.  Also, wikipedia says he is a vegetarian!

When I was a teenager one of my favorite science fiction books was “Permutation City” by Greg Egan.  In his novel virtual humans solve the problem of processing power and hardware by taking advantage of what he calls his “Dust theory”.  It has been years since I read it, so I wont attempt to botch a retelling of his ideas, but a similar concept was proposed by Max Tegmark (http://space.mit.edu/home/tegmark/crazy.html).  He posits that every mathematical system implies a physical universe, and if that system of sufficient complexity so that it can describe self-aware entities, then those entities will experience a physical reality.  This concept comes with allot of metaphysical baggage about ensembles of mathematical universes, but it does suggest an interesting parallel to Greg Egans novel.  Lets say we have a computer program that is of sufficient power to simulate a human mind (making the big assumption that that is possible at all of course), and we create a virtual environment with which that mind can interact, sense, feel, etc. If the program is entirely deterministic, based on a set of initial conditions, and relies on no input from our physical world, then from the subjective experience of the human mind within the simulation it makes no difference if the program is actually run or not. Every thought it can ever have is already defined by the initial conditions and the complexity of the program. So why run the program at all?

Lets avoid the issue of what that implies about our own self-determination in this apparently fleshy reality, as almost any sensible person would, and go back to our energy problem.  Obviously the most efficient solution is to scan all our brains in such a way that they can be “run” as a computer program, define a sufficiently complex environment in which we can all virtually drink tea and discuss self-determinism in an ironic tone, and then never actually run the program.  Of course at this point we (the apparently real ones) should all commit seppuku, as the main character in Greg Egans novel does.  There we go, I told you Max Tegmark was the most efficient fuel.  But to be honest I would rather eat a good steak.

One last thing.  This article is mostly just for fun, but it does express one of my own personal opinions: that strong AI is possible, and that there is nothing so special about the machinery of the human mind. If you have a different opinion­­­­, please express in the comments!

neill

## Zombie… Research?

Some people, more than I’d have expected to, are investing quite some time in Zombie Research, but what is it about? In short: they’re inventing weapons, strategies, buildings, methods and techniques to survive to the Zombie Apocalypse. It might seem a bit naive if your not into Zombies (I obviously am) but it may have its payoff in a near future.

## Best Weapon

Have you ever asked yourself what would be the best weapon to use on a Zombie scenario? I did, maybe you don’t, but someone really spent some time investigating the issue and he found out that a katana, although fascinating, is probably not the best weapon to defend yourself. Some gun experts have also been asked to judge which firearm would work best, keeping in consideration several factors, not only including the stopping power but also the weapon’s reliability, ease of use, accuracy, how long it’s able to operate without maintenance and so on.

## Zombie-Proof Building

One contest I particularly like is the Zombie Safe House Competition where a lot of architects, and not only them, compete to create the “house” you’ll want to get stranded in when the Zombie Apocalypse begins. The results are really surprising and every project is not only really smart, but also cared of to the last detail. It’s not just people throwing ideas, they’re designing projects capable of working… Potentially at least. As an example just take a look at the winner of 2011 contest, and to the second place. The first one is a bio-inspired feature-rich shelter, the second one a fully independent house. Are you getting my point? Not yet?

## Tools for the show?

Other than a good weapon and a cool house to share with other survivors, you’ll also need some tools, most probably you’ll have make a run to the pharmacy one day, or to the bar, depending on your needs. Whatever the story, a good survival kit will be needed, so what’s best to carry on? Of course someone took the effort to assemble a kit that might come in handy in those situations, and believe it or not it became a business. Try to search for “zombie survival kit” on google and you’ll see how much offer there is, many websites have been overwhelmed by the unexpected volume of orders. Of course there are even kits to use for when YOU will be turned into a zombie.

Let’s face it: most of us will be zombies, just a few lucky people will be on the human-side of the apocalypse, and for sure you don’t want to rot in the middle on nowhere, without your precious legs waiting there for the eternity right? Well if physics is of any consolation, it will probably be a much shorter time, but just in case be prepared.

How does a Zombie virus spreads? Will it be airborne? Waterborne? Carried by a bite, a scratch, an animal, an insect, rotten cheesecake? Who knows, and that’s good enough: we can prepare for a wider scenario, the first thing to keep in mind is: expect the unexpected. Believe it or not, some insects can carry a virus that’s able to turn the victims into some kind of Zombie, leading other insects to “controlled” behaviors. Want an example? Caterpillars are “forced” to climb the tree they live on, then they simply die and rot at the highest point where it’s easier for the virus to spread again. There are parasites that are able to make ants run away from their anthill, climb some leaves where they can be seen and eaten from birds… Where the parasite can easily reproduce and proliferate. There are many more examples, this was just an overview to show your that Zombies are already among us! Hey do you have a cat? Ever heard about toxoplasmosis? No? Well it’s time for you to find out.

## How This Kind of Research Might Really Save Us

I hope you had as much fun reading this post as I had writing it. Anyway my intent was to raise a question: can this type of research become useful some day, or is it just a waste of money and time? And make a point: yes it will be useful, possibly (but hopefully not) a lot! Zombie is just a  word that pictures in my mind the image of a green-gray guy making growling noises while walking awkwardly toward someone, trying to get a bite of his butt. Indeed it can be much more than that. Sure you can tell people to prepare for any type of disaster, but invariably no one will ever take it seriously until it’s too late (except for Japanese people, they do drills every time), and the laziness will always win. As an example take a pretty real threat: meteorites. Every once in a while we get news about some meteorite popping up from the darkness of space, totally undetected from our sophisticate detection network that has a low chance, let’s say less than 0.1%, of coming in a collision course with our beloved Earth. This happens more often than you might think, and except from Bruce Willis, who really tried to go first hand with a solution, nobody has really developed a working solution for an imminent impact event, and again: this is a real threat that one day or another we’ll have to face. If you tell people to prepare for a pandemic, for a prolonged period of scarce resources, for an invasion of grasshoppers what do you think everyone is going to do? Including you and me… Nothing. I’ll probably bring a scarf with me for the first event and a frying pan with some oil for the second… A towel maybe.

## Playing as a Way of Learning

I for one welcome our new zombie-overlords.

Alberto

Ramen

ps

Just so you know: what I’ve written above doesn’t hold in case of an alien invasion, it doesn’t matter what you’ve learned watching Independence Day: there’s no cross-platform virus able to run on an alien computer, if they will come and they’re evil we are completely screwed, resistance would be futile and dangerous, don’t even fight unless you like pain. You’ve been warned.

## Geeky and Goedely

Professor Brukner recently invited me to visit and give a talk in Vienna.
I deeply suggest everyone interested in foundational issues to check out his group’s work, they do really amazing stuff: from probing Planck physics with quantum optomechanics to finding physical constraints on general probabilistic metatheories.

By the way the University of Vienna is a rather majestic place, and look where I gave a talk

Goedel Lecture Room! Yes know, the photos are crappy, but I felt like a sort of geeky fanboy taking photos of the seminar room, so I tried to do it as quickly as possible.

I gave a talk on Quantum Carnot Theorem (the talk is here). Of course it ended up in a brawl, as each time I talk of this topic, but I think I am getting good at it, as the fight was quite limited, more a cane fight in London’s slum than the three-hours-long Royal Rumble of the first time I presented it at Nori’s Digital Material Lab.

Simone

## 3D Life

Recently I got into an end-of-the-night discussion about using a 3D version of
Conways’s Game of Life (GOL) to realize 3D trippy videos (I guess everything started from here).

Actually I wasn’t really familiar with GOL, apart having read Wolfram’s NKS, but the idea seemed fun, so I spent a couple of hours on the subject.

GOL is a 2D cellular automaton in which the state of a cell (alive of dead) at a certain timestep is determined by the number of its alive neighbors at the previous step. Calling $$S_t(j)$$ the total number of living neighbors of cell j, the evolution follows the following rules

1. $$S_t(j)<2$$ or $$S_t(j)>4$$: If cell $$j$$ is alive, it dies
2. $$1<S_t(j)<4$$: If cell $$j$$ is alive, it stays alive
3. $$S_t(j)=3$$: If cell $$j$$ is dead, it becomes alive

While unknown by the large public, this little game has generated a remarkable interest in the geek and research communities (and having to be interpreted mainly in the logic sense I guess).

I invite you to read the wiki page if you are not familiar with the usual 2D GOL

Just to highlight a few geeky points:

While some people had studied 3D GOL, and even published something on it:

C. Bays,  A note about the discovery of many new rules for the game of three dimensional life,
Complex Systems 16, 381  (2006).

on the net I could not find a ready to use code  (except this applet) so I wrote a program in Matlab and played a little bit with it. You can find it here. The output is an .avi file representing a 2D cut of the 3D grid.

[media id=1]

There are multiple ways to extend GOL to multiple dimensions. In the program (that implements a standard cubic lattice) each game is characterized by two lists of integers: Risefromdeath and Stayalive.

At the end of each turn the cell $$j$$ is alive if it was alive at the beginning and $$S_t(j)\in$$ Stayalive or it was dead and $$S_t(j)\in$$ in Risefromdeath. It is dead otherwise. So for example the usual 2D GOL would have Stayalive=[2,3], Risefromdead=[3] .

I only tried a few parameters and then got bored, but it turns out that for the right parameters the equilibrium structure is given by 2D parallel surfaces that intersect in the 3D space, with dynamical structures living on the surfaces. As the surfaces intersect, they give rise to islands that trap the dynamics. The video above is an example with Stayalive=[6:12] and Risefromdead=[6:9].

Now it could be interesting (at least for some peculiar definition of interesting) to extend this to N dimensions and to study the probability of having living structures as a function of the dimensionality.

To make this formal we should define an uniform measure over the set of rules and initial condition, and describe something as living if it has a nontrivial dynamic  (trivial to be defined accordingly to the dimension of the grid and of the expected Poincaré period I guess).

Dimensionality has a lot of importance in physics, especially in statistical physics. In particular mean field theories become more accurate at higher dimensions (higher dimension=more neighbors). Is there a link with the emergency of interesting dynamical structures? Is there a dimension range in which it is more probable to observe interesting life like structures? In the hypotesis that this range exists, is small, and centered around 3, would be possible to find someone who can claim, with a straight face, some link with the anthropic principle?

Actually I have no idea and I do not think I will spend time on the question anytime soon, but if  you find something amusing let me know!

Simone