Wednesday, September 5, 2007

It’s simulations all the way down!

My buddy RT told me about something called The Simulation Argument. It's a simple argument consisting of a few reasonable statements which – when taken together – basically guarantee something that you probably won’t like.

It isn’t a proof – it’s just something to think about:

The Simluation Argument*
A) It’s possible to create a computer simulation of individuals with artificial intelligence.
B) An A.I. individual inside the simulation wouldn’t know that it’s inside a simulation – it would just be going about its daily business in what it considers the “real world”.
C) A civilization that did develop such a simulation would run it many – say millions – of times (for fun; for research, etc.)

That's it, that's all there is to it. What do you think - is any one of these statements totally unreasonable?

Well if they sound even somewhat plausible to you, then ask yourself this: which of the following is more likely?

  • That we are the one civilization mentioned in C) which happens to develop the ability to run A.I. simulations? Or,
  • That we are one of the millions of simulations that civilization C) has run?

Remember: we wouldn't know if we were in a simulation (point B); and there have been way more A.I. civilizations simulated than there have been "real" civilizations in the "real" universe (point C).

To put it another way, suppose there are 1,000,000 intelligent, self-aware civilizations in the universe…But only 1 of them is “real” while 999,999 are A.I.’s. Every one of them feels like it is “real” and lives in a “real” universe.

Are we the one in a million? Or just one of millions? Well, are you a betting man/woman/simulation?

If so, let's play a game. The game gives you just as good a chance of winning as we have of being the one "real" civilization mentioned in point C:

You and the Simulation Argument will both pick a number between 1 and 1,000,000. If the numbers match, then you win and we are the “real” civilization. But if the numbers don’t match, then the Simulation Argument wins and we’re just one of the many A.I. civilizations being run by the “real” civilization on their fancy computers.

Ready? Remember, the fate of humanity rests on your shoulders, here. Are you sure you’re ready?
If you are, then pick your number between 1 – 1,000,000 and click to see what number the Simulation Argument chose:


Good try!! Too bad about the fate of humanity…
...Do you feel any different? Are we any less “real”?

Switching gears for a moment, here’s an argument which isn’t quite as credible. I stole it from Stephen Hawking:

The Old Lady’s Argument
A well-known scientist (some say it was the philosopher Bertrand Russell
) once gave a public lecture on astronomy. He described how the Earth orbits around the sun and how the sun, in turn, orbits around the centre of a vast collection of stars called our galaxy
At the end of the lecture, a little old lady at the back of the room got up and said: "What you have told us is rubbish. The world is really a flat plate supported on the back of a giant tortoise
The scientist gave a superior smile before replying, "What is the tortoise standing on?"
"You're very clever, young man, very clever," said the old lady. "But it's turtles
all the way down!"

I like that little anecdote (clearly the old lady's position is ridiculous, but I’m curious as to why she chose turtles…)

Anyway, if you're wondering why I brought up both of these arguments in the same post…there’s a subtlety to the Simulation argument that really comes across as a kick in the, er, teeth:

Suppose that you accepted the Simlulation argument (or lost the number-matching game!), and we are just one of the millions of simulations that have been run by civilization C. Then at least we’re just one step away from the “real” universe, right?

…But when you accepted point A ('it’s possible to create a computer simulation of individuals with artificial intelligence'), you probably did so because we’re pretty close to developing such A.I. for ourselves…But remember - we've already figured out that we ourselves are just a simulation...which means that any A.I. entity we someday create won’t just be a simulation – it’ll be a simulation inside a simulation!

Sucks to be them!

But…this actually reveals the truly awful truth: odds are, we’re not just one of the simulations run by “civilization C”, after all. Odds are, we’re just one of the simulations run by a simulation run by a simulation run by a simulation run by a simulation (go ahead and repeat “run by a simulation” as many times as you like here) run by a simulation run by the “real” civilization C.


A well-known scientist (some say it was the philosopher Bertrand Russell) once gave a public lecture on astronomy. He described how the Earth orbits around the sun and how the sun, in turn, orbits around the centre of a vast collection of stars called our galaxy.
At the end of the lecture, a little old lady at the back of the room got up and said: "What you have told us is rubbish. The universe is really an A.I. simulation running inside another civilization’s computer."
The scientist gave a superior smile before replying, "What is
civilization’s universe like?"
"You're very clever, young man, very clever," said the old lady. "But it's simulations all the way down!”

The End.

PS: I suppose at this point I’d better say, “Thank goodness the old lady is crazy, the Simulation argument is ridiculous, and even if it weren't then clearly we are the one lucky civilization in a million million million million million which actually lives in the real universe.”
…But then again,

* The Simulation Argument was
invented by Nick Bostrom.

Monday, August 27, 2007

Zombie Ants from Outer Space

I promised myself that I wouldn’t do another post with a biological example of the viral model so soon, but Mike the Boyfriend (my sister’s boyfriend, not mine) just told me about this and it’s too cool to delay.

Ok, I admit it, the heading’s a tad misleading: the ant isn’t actually undead, nor is it from outer space. But “Dicrocoelium dendriticum” just wasn’t a very compelling title.

Anyway, there’s a parasite out there that can sneak inside the still-living body of an ant; take control of it; and force it to behave in a suicidal manner. The parasite is called a Lancet Fluke, and it sure jumps through some hoops in order to achieve its purpose; a wonderful example of very specialized adaptation.

The Fluke’s ultimate target is the belly of a herbivore such as a cow or sheep.

This is how it gets there:

Thousands of fluke larvae snuggle into a nice big pile of herbivore poop*
A snail comes along and eats the poop (accidentally ingesting a bunch of fluke larvae).
The snail wanders around, leaving a trail of ooze riddled with now-juvenile flukes.
An ant comes along and eats the snail-ooze. No, really!**
When it eats the snail-ooze, the ant unwittingly eats hundreds of juvenile flukes.
One lucky fluke navigates inside the ant to its brain, nestling in to the area that controls movement and mandibles:

  • While the temperature is warm – daytime – the fluke does nothing. This allows the ant to act normally during the day when all the other ants are active.
  • When the temperature drops below 10C – nightfall – the fluke takes over. It makes the ant climb a blade of grass and latch onto it with its mandibles. The ant remains suspended from the grass all night.

  • When the temperature rises above 10C again – daytime – the fluke relaxes control and the ant resumes its normal activity.

This cycle continues until a herbivore who is out for a stroll one evening happens to eat the blade of grass – ant, flukes and all.
The herbivore digests the hapless ant, releasing the flukes who spread out into its stomach where they can meet like-minded individuals.
Pairs of the now-adult flukes perform a special hug which results in the creation of a fluke egg.
The unlucky host of the party stops eating; it weakens and eventually dies. But before passing on, the herbivore – you guessed it – poops out the fluke eggs, taking us all the way back to step 1.

As I mentioned up top, this is another example of the viral model:

The fluke spreads to ever more sites by hitching a ride on snails then herbivores then snails etc, occasionally getting carried by one of them to a new place it's never been before.

I know this whole process sounds like it comes from a bad ’60’s movie, but it’s real and actually pretty neat. Makes you wonder, how on earth did the fluke evolve in such a specialized manner..?

...And are there any other mind-controlling parasites out there? (Hint: yes.)

(I learned most of this from and some of it from Behavioral and Morphological Changes in Carpenter Ants Harboring Dicrocoeliid Metacercariae, Carney 1969.)

* I’m sorry that 2 out of 3 posts involve the wonders of poop as a transport mechanism. I’m not obsessed with the idea; apparently excrement is just far more useful to the parasites of the world then I ever knew***!

** If you think eating snail-ooze is gross, then why didn’t you complain about the part where the snail ate the herbivore crap?? Maybe you’re just more open-minded than I…although I think that this would show rather conclusively that open-minded people contain fluke worms…

*** By the way, this is why you’re supposed to wash your hands after going to the bathroom! Who knows, if too many people ignore this rule, maybe a similar parasite will evolve that causes people to leave the norms of human society and stay up all night consuming grass…Wait a second: are we too late?? Is it
already among us…?

(picture found randomly at

Tuesday, August 7, 2007

The Viral model giveth, and it taketh away

So the last post showed one way in which a species improved its odds of success in the world by harnessing the power of the viral model. Here's a look at another organism which uses the model to deadly effect, simultaenously strengthening its species while devastating another.

Behold the Mountain Yellow-Legged Frog!

Doesn't look very threatening, does it?
...And actually, it isn't. But this is:

That is a picture of Batrachochytrium dendrobatidis (Bad End, if you will) - a fungus which is lethal to various amphibian species such as frogs, toads, and salamanders. In this picture, the fungus has taken up living under the skin of some hapless mountain frog. The frog won't survive this encounter - it's headed for a bad end.

The fungus reproduces by firing a spore (a fungus seed) out into the world. The Bad End spore lives in water, mud, and dirt; it is very tough and has been shown to survive up to 10 years in a site without a host.

Nobody knows exactly how Bad End kills its host, but we do know that it has spread - fast. The spores are skilled at catching a ride on the feet of passing animals - including the people who are actually out there researching the Bad End! This allows the spore to hitchhike out of the immediate area and spread the species to more and more sites.

Does that ring any bells? How about this?

Why do we care? Well, to quote somebody smarter than me*:
"Over the past 30 years, [the frog] has disappeared from up to 95 percent of its historic range, and its absence is impacting other organisms. Garter snakes that used to prey on these frogs are now declining. The frog's decline is leading to an unraveling of a high-elevation ecosystem."

Unraveling ecosystems are A Bad Thing. Even if you have zero ounces of pity, or (correctly) consider this just another case of natural selection determining which organisms deserve to survive, you may well enjoy the predictability of your daily life as a human being in an affluent society. The destruction of entire ecosystems can have unpredictable effects: the world is a complex system, and the obliteration of a big chunk of it can really come back to hurt us and our way of life in ways we can't predict.

So you don't even have to be nice to want to help the frogs - you just have to be selfish!

*I learned about chytridiomycosis here and here.
(frog image from this site, where it is credited to David Liittschwager.)
(fungus image lifted from this site, where it is credited to A. Pessier, University of Illinois.)

Monday, July 30, 2007

Poop - relieving the pressure of natural selection!!

One of the purposes of this blog is to gather together some of the neat things I come across while studying complex adaptive systems. Here is an example:

Endozoochory is the dispersal of seeds through animal ingestion and excretion. This is a strategy used by some plants to improve the odds of their species surviving: get yourself eaten by a creature, but make sure your seeds resist being digested by that creature. When the creature has its next poop, it returns your seeds to the earth along with their own personal pile of fertilizer!!

This is neat because it shows how the creature and the plant really help each other out. The more the creature eats, the more the plant flourishes; the more it flourishes, the more the creature *can* eat next year, and so on.

The immediate result is that the plant should thrive around the creature's home - call it site A.

But going a step further, suppose the creature is migratory: then the plant also gets the chance to colonize sites along the creature's migratory paths. Let's say that the plant starts out only at site A, but there are also sites B & C which are inaccessible to the plant (maybe because it's too far away for a random gust of wind to blow the seed over from A.) Over time, as the creature migrates from A to B, it carries the seeds of the plant and poops them out along its path (essentially planting its own lunch for next year's migration...) The result of this process is that the plant is able to spread to B.

And finally, the really big payoff is that the plant gets the chance to colonize areas visited by *other* creatures who happen to pass through site B - creatures it never would have met in site A! Such a creature never visits site A but does visit sites B & C: once it finds the plant growing in B and eats it, the creature can spread the plant to C.

And now realize that at each previously-inaccessible site, there's probably a few more creatures which can eat the plant, and that they each have their own set of sites that they visit...You can see what a powerful means of reproduction endozoochory is.

PS: This spread of a seed through the world via excrement reminds me an awful lot of Facebook gimmicks (and contagious diseases; and catchy tunes; and parasites; and fashion trends; etc...): Suppose a group "A" is all the people who routinely check out brand new Facebook gimmicks - this is just a tiny subset of all the people out there who use Facebook. But if just one person from group A adds a new Facebook gimmick to their page, all of their friends (group B) suddenly see it; when someone from group B adopts the gimmick, all of her friends (group C) suddenly see it; etc. In the end, the gimmick propagates far beyond just the people in group A.

The point of all this is that if you are like my sister's boyfriend and loathe Facebook, then at last you can point to this blog and say that people who use Facebook are simply shovelling crap from one person to another.

Wednesday, June 27, 2007

Why do we care??

One of the key concepts in CAS is that the behaviour of the system isn't easy to predict. So if you reach in and poke some element of a complex adaptive system, you can't know for sure what the eventual outcome will be (remember the monkeys around the campfire - was the difference between an opposable thumb and a prehensile tail really so significant??)

And yet every action humanity takes - a single person writing a blog, or a company accidentally spilling oil into the ocean - is poking a CAS on some level. So there are billions of people out there interacting with many levels of CAS every second of every day...And yet by the definition of a complex system, the outcome of all these interactions is difficult to predict.

Giving a monkey a thumb didn't change the world overnight, but over millenia, the ripple effect has been huge. How could anyone have predicted this? Between the monkey and an octopus, I probably would have bet on the octopus being the one to take over the world...After all, it's got eight bloody arms to figure out how to make a good cup of coffee!

Our problem is that in complex adaptive systems, changes are constantly occurring - how do you know which one will have a significant impact? Especially when the impact can take a long time to become apparent?

The evolution of the thumb is a perfect example of a lever point: a small change with a big impact.

Figuring out how to identify the lever points in a given system is a huge motivation for the general study of CAS. I would almost define "self-preservation" as identifying the lever points in the systems with which you interact, then doing your best to push the good ones and prevent the bad ones.

What are CAS??!

A single person
Bee hives
The Earth and everything in it.

All of these are CAS - complex adaptive systems.
"System" because the whole is made up of many smaller parts (for example, all the businesses in a market; but don't forget their suppliers; and their consumers; and their employees; and...)
"Adaptive" because the smaller parts change over time depending on their situation (which organisms evolve to prosper in a particular ecosystem over time...and which die out?)
"Complex" because...well...the behaviour of these systems isn't always easy to understand or predict. If you sat down around a campfire a bazillion years ago with all of the primates in the jungle and asked, "what would happen if I gave one of these guys an opposable thumb instead of a prehensile tail?" your answer probably wouldn't have been "Well, that one guy would become the most dominant species on the planet, and along the way develop self-awareness, technology, language, etc."
And yet that very thing happened because our ancestral primate existed in a system made up of many independant, evolving parts. The interactions between all the parts of that system range from the obvious (the guy with the thumb got better at killing animals for food once he figured out how to throw a spear) to the obscure (when a single-celled organism called Phaeocystis globosa is eaten by bigger creatures, it helps reduce the amount of carbon dioxide in the atmosphere; but when it is eaten by smaller creatures, it doesn't...)

The whole point is that the universe is full of complex interactions, and yet by their nature we have trouble connecting the dots. By studying CAS, we're trying to understand some general rules about how these complex interactions work, whether we're looking at an ecosystem, a market, or the blood cells in your body. Hopefully we can get to a point where every time we learn more about one particular system, we learn more about all the other, unrelated systems too.

We're trying to connect the dots.

Hello world!

Hi there, welcome to my blog about complex adaptive systems and related concepts.

I'm no kind of expert about anything - I'm a computer and games nerd. But I've started looking into complex adaptive systems - CAS - since reading John Holland's book Hidden Order. This blog is a place to organize the stuff I've found most interesting; to hopefully distill some of the more difficult concepts into something easier for other newbies to manage; and to eventually share some computer programs I've written to help explore the behaviour of CAS.

Remember - I'll probably get a lot of this stuff wrong. I'm not qualified to "lecture" about any of this. But I occasionally come to my own conclusions after reading work by the people actually defining this field, and I plan to share them. So take me with a grain of salt!!!