Speeding up supercomputer simulations using Einsteinian relativity

Writing in Technology Review, Christopher Mims is reporting on how physicists will soon be able to use Einstein's relativity to speed up supercomputer simulations by as much as 10,000%. He says it's not the algorithm or the hardware, but the reference frame that needed an update:

Physicists realized that because the laser is accelerating electrons in its path to nearly the speed of light, Relativistic effects start to be a big deal - the same effects first discovered by Albert Einstein.

And if we remember anything from A Brief History of Time or even the original Planet of the Apes, it's that at speeds approaching the speed of light, where the observer is standing has a huge impact on what they perceive - this is, for example, the reason that an astronaut traveling close to the speed of light would age much slower than the people he or she left behind on earth.

Previously, all simulations of laser-plasma accelerators were run from the perspective of a physicist standing somewhere in the vicinity of the experiment - in other words, someone who sees a super short laser pulse traveling at a near-stationary plasma. Mathematically, this is very hard to simulate - the laser is brief.

But what if, instead, we take the perspective of the plasma itself? Now, relative to the laser, it's as if the plasma is traveling toward the beam of light at near-light speed. Because of relativistic effects, this stretches out the beam of the laser, making it longer and mathematically more tractable to simulate.

Voila - the resulting algorithm is hundreds of times faster than previous attempts to simulate a laser-plasma accelerator.

Source.

Welcome to the Machine, Part 5: Simulation taxonomy

Previously in series: The Ethics of Simulated Beings, Descartes's Malicious Demon, The Simulation Argument, Kurzweil's Nano Neural Nets.

As shocking as the Simulation Argument is, it's (arguably) a revelation that's no less shocking than previous existential paradigm shifts. While undoubtedly disturbing to the people alive at the time, previous civilizations have come to grips with the knowledge that they do not live on a flat Earth nor at the center of the Universe.

Like the simulation argument, these previous scientific epiphanies assaulted humanity's sense of itself and its cosmic importance within the Universe. But just as it no longer troubles us to know that we don't live at the center of the Universe, it shouldn't bother us to know that we don't reside in the deepest reality. While it's tempting to diminish the "realness" or the validity of a virtual world, so long as certain attributes of existence exist, there's no good reason to value one realm over another.

This being said, there are a number of unanswered questions about the type of simulation we could be living in—answers to which could have a profound impact on our self-conception.

We do not have the means yet to determine whether or not we live in a simulation, let alone the means to determine its potential type and nature. But this hasn't prevented serious speculation; we may be able to describe and categorize the possible simulation types and varieties of virtual life:

Hard and soft simulations

The possibility exists, for example, for what philosopher Barry Dainton describes as hard and soft simulations. Hard simulations result from directly tampering with the neural hardware ordinarily responsible for producing experience whereas people running in a soft simulation have no corporeal source—they are exclusive streams of consciousness generated by computers running the appropriate software; there is no external hardware support.

The inhabitants of The Matrix had bodies that existed outside of the simulation, thus qualifying it as a hard simulation. Sensory experience could be directly machine-controlled through the stimulation of the appropriate areas of the sensory cortex and the movements of the simulated body would be under the control of the source mind, but there would be no need for the source body to actually move. As Morpheus noted, "What is real? How do you define real? If you're talking about what you can feel, what you can smell, what you can taste and see...then real is simply...electrical signals interpreted by your brain."

Complete and partial simulations

There's also the possibility for complete and partial simulations. In a complete simulation, every element of the experience is generated by artificial means (e.g. the complete suppression of all psychological characteristics (including memory) in favor of novel ones) .

But in a partial simulation only some parts or aspects of the experience are generated artificially (e.g. the person retains their individual psychology).

Active and passive simulants

Dainton also describes active and passive simulants. Actives are completely immersed in virtual environments, but they are in all other respects free agents—or, as Dainton concedes, free as any agent can be. Their actions are not dictated by the program, but instead flow from their own psychologies, even if these are machine-implemented.

Passive subjects, however, have a completely preprogrammed course of experiences. "The subjects may have the impression that they are autonomous individuals making free choices," writes Dainton, "but they are deluded." All their conscious decisions are determined by the program. They have apparent psychologies, and are conscious, feeling agents, he notes, but their real psychologies are entirely suppressed or nonexistent.

Original and replacement psychologies

Other varieties of simulated life include subjects who have either retained their original psychologies or are given entirely new ones. In an original psychology simulation, a simulant has an external existence outside the simulation and retains their original psychology -- again, The Matrix provides a good example. But in a replacement psychology situation, the simulant has external existence, but none of the original psychology is retained, only consciousness is transferred.

Communal and individual simulations

Simulation experiences could also be communal or individual.

Communal simulations have a virtual environment that is shared by a number of different subjects, each with individual and autonomous psychological systems.

In an individual simulation, however, there is only one real subject with an autonomous psychology; the other "inhabitants" of the simulation are merely automatons, parts of the machine-generated virtual environment. Communal and individual simulations could also be combined, where 'real' psychologies are intermixed with automatons. This scenario is (somewhat) explored in the 1999 film, The Thirteenth Floor.

Combinations

Which leads to the next level of complexity, the idea that these simulation types could be mixed and matched. Indeed, if powerful simulation technology were to be commonplace it is by no means inconceivable that these simulations, particularly those of the hard variety, would be generated in sufficient numbers.

One thinker who has thought of the various different combinations is Tony Fleet. While there are as many as 32 different combinations, he argues that only 9 of them are viable and/or logically consistent. For example, in a partial simulation scenario, an external entity it required -- therefore this is only possible in the hard simulation case; a partial soft simulation is therefore impossible.

Fleet speculates that the only viable combinations can involve the communal/active; individual/active, individual/passive simulation types (be sure to check out his tables). That said, he does not believe that we've covered all simulation types. For example, there is no distinction between physical, virtual and mixed simulations. Some more work clearly needs to be done to create a complete simulation taxonomy along with all logically consistent combinations.

Posthuman vacations

This opens the door to some remarkable possibilities. How might these simulations and virtual reality experiences be utilized by our descendants, or even our future selves?

It's conceivable that people might take virtual reality 'trips' to the past quite frequently. They would also likely be used on an occasional basis during history lessons for those with a particular interest in experiencing what it was like to live during certain periods of the past (Bostrom's Ancestor Simulations come to mind).

But such trips might also be taken for entertainment purposes. A future activity in a posthuman world might very well involve regular immersive and interactive journeys into simulated realities. And in order to increase the authenticity of such adventures, it's quite possible that posthumans may choose to temporarily suppress their psychologies and memories. Of course, they would recall the entire experiencing after re-awakening in their genuine reality as their authentic selves.

Which means that you might actually be an autonomous simulant with a replacement psychology living in a hard simulation.

And if that's the case, now what? How are you supposed to live?

A topic I'll return to in my next post.

Welcome to the Machine, Part 1: The ethics of simulated beings

Without a doubt some of my favorite video games of all time have been those that involve simulations, including SimCity and The Sims.

When I play these games I fancy myself a demigod, managing and manipulating the slew of variables made available to me; with the click of a mouse I can alter the environment and adjust the nature of the simulated inhabitants themselves.

There's no question that these games are becoming evermore realistic and sophisticated. A few years ago, for example, a plug-in was developed for The Sims allowing the virtual inhabitants to entertain themselves by playing none other than SimCity itself. When I first heard about this I was struck with the vision of Russian Matrioshka nesting dolls, but instead of dolls I saw simulations within simulations within simulations.


And then I remembered good old Copernicus and his principle of mediocrity: We should never assume that our own particular place in space and time is somehow special or unique. Thinking of the simulation Matrioshka, I reflected on the possibility that we might be Sims ourselves: Why should we assume that we are at the primary level of reality?

Indeed, considering the radical potential for computing power in the decades to come, we may be residing somewhere deep within the Matrioshka.

Consequently, we are all faced with a myriad of existential, philosophical and ethical questions. If we are merely simulants, what does it mean to be alive? Are our lives somehow lessened or even devoid of meaning? Should we interact with the world and our fellow simulants differently than before we knew we were living in a simulation? How are we to devise moral and ethical codes of conduct?

In other words, how are we to live?

Well, there's no reason to get too excited over this. It's a bit of speculative metaphysics that doesn't really change anything -- assuming we are in a simulation, we should live virtually the same way as if we were living in the "real" world.

That is unless, of course, those running the simulation expect something from us. Which means we need to figure out what it is exactly we're supposed to do...

Tomorrow - Part 2: Descarte's 'Malicious Demons.'

The perils of a digital life

I've written about potential inhibitors to consciousness uploading in the past, but I believe I've come up with another possible problem for those wishing to live a purely digital life. It may very well turn out that, as a medium, digital substrate is far too insecure and algorithmically unconstrained. This could eventually lead to intractable complexity. Put another way, a digital existence may be too open-ended and diverse for there to be any kind of stability.

Virtual reality environments and MMORPGs are giving us the first clue that this may be a problem. Take Second Life, for example, which is already experiencing a number of strange anomalies and issues. In the past year SL users have had to deal with CopyBot, CampBots, SheepBots, grey goo, and alt instances.

Each of these are headaches unto themselves, and possible harbingers of more severe problems to come.

Virtual nuisances

CopyBot was originally created as a debugging tool by the SL development team and was intended for functions like import/export and backing up data. But as is so often the case with technology, it was twisted and used for an entirely different purpose altogether. Some opportunistic Second Lifers used CopyBot to duplicate items that were marked no copy by the creator or owner, thus violating intellectual property rights. To date, attempts to counter CopyBot have included anti-CopyBot spamming defeaters, which have in turn given rise to anti-anti-CopyBot defeaters. Call it an algorithmic arms race.

While this hints at post-scarcity and open source, it is still unclear how unbridled duplication will offer users the incentive to create original artifacts for the SL environment.

CampBots and SheepBots aren't nearly as contentious, but are equally annoying. These are essentially SpamBots working under the guise of an avatar.

And back in October of 2006 users experienced a grey goo scare when a "griefer" (a person who disrupts video-games) attacked Second Life with self-replicating "grey goo" that melted down the SL servers. The griefers used malign scripts that caused objects to spontaneously self-replicate. According to the the transcript of the SL blogs:

4:15pm PST: We are still in the process of investigating the grid-wide griefing attacks, as such we have momentarily disabled scripts and “money transfers to objects” as well on the entire grid. We apologize for this and thank for your patience. As soon as I have more information, I will pass it along.

4:35pm PST: As part of our effort to counter the recent grey goo attacks, we’re currently doing a rolling restart of the grid to help clean it out, this means each region will be restarted over the course of the next few hours. Thanks again for your patience.

4:55pm PST: There was a slight delay to our rolling restart while we continued our investigation. The rolling restart should begin soon, if you are currently in-world you will get a warning before your region is restarted - allowing you to teleport to another region. We hope to have logins open again very soon. Thanks again for everyone’s patience during this issue.

More recently SL users have had to compete with so-called alt instances who launch ultra-fast bots that scoop up valuable land; automated bots work with much greater efficiency than humans. Alt instances are additional avatars controlled by the same user. They do this to capitalize on on the First Land privileges that are extended to newbies. It is estimated that users have on average 1.25 avatars, indicating that there may be as many as 500,000 in-world alts.

These bots have created a huge digital scarcity because Second Life has been overwhelmed with the groundswell of new residents. Users have asked that these bots be made illegal and Linden Labs has agreed to look into it.

Our analog, digital and future worlds

As I look at these examples I can't help but think that virtual reality environments are offering a glimpse into our future -- both in the analog and digital arenas. Second Life in particular is a mirror of not just our own society, but of future society itself. In real life we are dealing with the widespread copying of copyrighted material, issues of open source, out of control spam, the threat/promise of automation, molecular fabrication, and of course, the grim possibility of runaway nanotech.

Moreover, an uploaded society would conceivably face more problems in digital substrate than in the cozy confines of the analog world. We can't 'hack' into the code of the Universe (at least not yet). As a consequence our existence is still very much constrained by the laws of physics, access to resources, and the limits of our information systems (i.e. our accumulated body of knowledge). That said, we do a fairly decent job of soft-hacking into the Universe, which is very much the modus operandi of an intelligent species.

But the soft-hacking that we're doing is becoming more and more sophisticated -- something that could lead to over-complexity. We're creating far too many dangerous variables that require constant monitoring and control.

As for the digital realm, it is already complex by default. But like the analog world it too has constraints, though slightly different. Virtual worlds have to deal with limitations imposed by computational power, algorithmic technology and access to information. Aside from that, the sky's the limit. Such computational diversity could lead to complexity an order of magnitude above analog life.

Hackers and criminals would seek to infiltrate and exploit everything under the virtual sun, including conscious minds. Conscious agents would have to compete with automatons. Bots of unimaginable ilk would run rampant. There would be problems of swarming, self-replication and distributed attacks. And even more disturbingly, nothing would be truly secure and the very authenticity of existence would constantly be put into question.

Perhaps there are solutions to these problems, but I'm inclined to doubt it. Natural selection is unkind to overspecialized species. Further, we have no working model of evolution in digital substrate (aside from some primitive simulations).

This is one case where I certainly hope to be proven wrong.

Bjork's colonization simulation does not explain Fermi's Paradox

A number of science sites are proclaiming that the Fermi Paradox may have been solved by Rasmus Bjork, a physicist at the Niels Bohr institute in Copenhagen. Unfortunately, his claim does not withstand scrutiny; the Fermi conundrum is still far from being answered.

Bjork is making a point that many others have made before, that ETI's have not had enough time to colonize the Milky Way. What makes his claim different, however, is that he used a computer to simulate the migrational spread of intergalactic probes.

In his simulation, Bjork had a single civilization launch 8 intergalactic probes to search for intelligent life. Once on their way, each probe would send out eight more mini-probes to search for the nearest stars and look for habitable planets. He was careful to set the parameters such that the probes would only investigate the galactic habitable zone of the Galaxy. Bjork also set it up such that the probes could travel at 30,000km/second, or a tenth of the speed of light.

Based on these settings, Bjork discovered that it would take these probes 10Gyr to explore a measly 4% the Galaxy -- roughly half the age of the Universe. This data would indicate that there most certainly has not been enough time for ETI's to thoroughly explore the Milky Way.

His analysis, however, fails to take into account the likely nature of intergalactic exploration and colonization. In Bjork's simulation, he tracks the progress of a mere 72 probes. Given this ludicrously limited strategy, it would take these 8 primary probes and 64 sub-probes 100,000 years to explore a region of space containing 40,000 stars. Such an effort would almost certainly be considered futile by any civilization, and it's doubtful any ETI would embark on such a project.

Instead, what Bjork should have considered is the potential for ETI's to proliferate Von Neumann replicating probes. Advanced civilizations with access to molecular assembling nanotechnology would be capable of launching self-replicating probes. Initially, the spread of Von Neumann probes would be slow, but like any exponential process, progress would eventually explode. It's been estimated that these types of probes could reach all four corners of the Galaxy anywhere from 5 to 50 million years. That's a far cry from Bjork's projected 250Gyr.

So, no, the Fermi Paradox has not been solved. Far from. And it's high time that cosmologists and astrobiologists stopped using technology from Star Trek to inform their research.