Hints That You're Living in a Simulation; Plus, What Is a Simulation?

See Bostrom's simulation argument for background. From a practical standpoint, you might be suspicious that you live in a simulation if you inhabit a world with the following characteristics:

Hint #1) Limited resolution. A simulation would be computation intensive. It would be useful to have tricks that increase the economy of operations, but in ways that do no compromise the consistency of the simulation to the players. One such trick would be to set an absolute upper limit to resolution (or a lower limit to the size of the elements that make up the "picture") that is below the sensory threshold of the players. These elements could variously be called pixels or quarks. Similarly, it would behoove the simulators to set a maximum time resolution, i.e. maximum frames-per-second, also called Planck times. Furthermore, the simulation's computing power is spared by a statistical method of calculating relationships between entities in the simulation (i.e quantum mechanics) even though it may look, at the scale of the game players or simulated entities, as if the universe maintained quantitative relationships in terms of integers calculated to arbitrary precision. (Related question: is it possible in principle given the physics of our universe for something the size of a bacterium or virus to "be conscious of" this gap in the behavior of the Newtonian and quantum realms, at a very basic sensory level? If not, isn't it interesting that our universe is such that there can be no consciousness operating on scales that would expose the twitching gears behind the scenes?)

Hint #2) There are limitations in what spaces within the game can be occupied by players or sims. In the old Atari 2600 Pole Position game, you couldn't just randomly go off driving off the track and through the crowd even if you didn't care about losing points; the game just wouldn't let you. Similarly, the total space in our apparent universe that we occupy, or directly interact with, or for that matter even get any significant amount of information from, is an infinitesimally small part of the whole. Unless you're in a submarine or in orbit, you don't go more than 200 meters below sea level or 13,000 m above it. (That's a volume of 2.1 x 10^18 m^3 that for all practical purposes the entirety of human history has occurred in; double that figure, and that's the volume that all of evolutionary history has occurred in.)

Hint #3) Beyond the "active game volume" as described above, dab a few pixels here and there in an otherwise almost entirely dark and empty volume. Make them so far away that sims can't possibly interact with them. Reveal additional detail as necessary whenever someone happens to look more closely at them. (And there's another trick: objects in this simulation are only loosely
defined until one of the players interacts with them, "collapsing the wave function". Yeah, that's what the programmers will call it, that's the ticket.)

Hint #4) Even in that limited location, make the active game volume wrap around. That way the simulators get rid of edge-distortion problems, as in Conway's Life. A sphere is the best way to do this. Therefore, work out the physics rules of the simulation to favor spheres.

Hint #5) Make each state of the simulation dependent on previous states of the simulation, but simplify by dramatically limiting the number of inputs with any causal weight. The simulators can limiting computations by having only mass, charge, space and their change over time determine subsequent frames.

Hint #6) If for some reason it is important for the entities in the simulation to remain ignorant to their existence as part of a simulation, the simulators could make sure the entities are accustomed to not only these kinds of stark informational discontinuities but to profound differences in the quality of awareness, both within themselves and each other. That is, the sims will accept not just that the vast majority of the universe (as seen in the sky at night) is interactively off-limits to them, but they'll also accept that their own awareness thereof and ability to connect the dots will dramatically vary over time. That way, if there is any need to interfere and make adjustments (to stop someone from figuring out the game) it won't strike the sims as strange. (Forgetfulness, deja vu, mental illness, drugs, varying intelligence or ability to concentrate on math, death of player-characters before they can learn too much?)

#6 does raise a very important question: why would the simulators give a damn if we knew we were in a simulation. So what? What would we do about it, sue them? If Pac-Man woke up and deduced that he were a video game character, if he still experienced suffering and mortality the same way, why would it matter? By this same view, there's an easy answer to whether we should behave differently if we're actually in a simulation: no. Whether our universe is in reality just World of Warcraft from the sixth dimension, if we simulated beings can suffer (and I know I can), then the moral rules are exactly the same as before.

It's also worth asking for some humility, and asking why we humans always assume that we would be the purpose of any such simulation. We could be merely incidental consciousnesses that are necessary for harboring the populations of simulated bacteria that the simulators are really studying. Or, the simulators could be cryonicists who preserve pets, and the most popular pets in their dimension look like what we call raccoons, and our universe is actually the raccoon heaven in which their beloved masked companions await a cure for the disease that forced the owners to put them on ice. In fact the raccoon-heaven simulation would contain a whole suite of ecosystem, all of them purely simulated (with the exception of raccoons) to keep up the appearance of a full biosphere. So the point of such a simulation would be to fool raccoons - or maybe even mice (again, why would they care about fooling everyone! If the simulators are reading this, just give me more juicy steaks and I won't make problems. It doesn't cost you anything!)

While the raccoon thought experiment is meant to be whimsical, a healthy respect for our own ignorance is always in order for these kinds of speculations. After all, assuming what we have guessed about the rest of (for the sake of argument simulated) universe is accurate, then there might be "aliens" (other non-human intelligences within the simulation) who may very well be much brighter than us. So even if the simulation is somehow arranged around the most intelligent entities within it (as we assume), those entities need not be human. Even if we're simulated, and we have a real brain and body in the "real" universe that's similar to our form in this one, this simulated universe might be designed for Martians (who are brighter than us) and be much less pleasant than our home dimension.

Finally, the very idea of a simulation is poorly defined. Mostly we think of something like almost completely controlled full-world simulation in the Matrix, but let's explore boundary cases. If I wear rose-colored glasses, is that a simulation (or a red world)? What about LSD that causes me to see unidentified animals scurrying past in my peripheral vision? What about DMT that causes a complete dissociation of external stimuli from subjective experience? What if I have some chip implanted that displays blueprints of machinery in my visual field a la the Terminator, is that a simulation? What about a chip that makes me see a tiger following me around that isn't there? (Hypothetical given current limitations.) What if I hear voices telling me to do things that are produced by tissue inside my own skull, by no conscious intent of anyone? (Not at all hypothetical.)

One of the interesting points in the popular movie Inception is the way that external stimuli appear in dreams. This gives us a hint as to what we mean by simulation, and why we care. Most of us have had experiences where the outside world "intruded" into a dream, with the stimulus obvious after we awoke. I once dreamed that a dimensional portal slid open in front of me with an ominous metallic resonance, and I stepped through it, suddenly speeding over the red, rocky surface of Mars. Then I realized it was my father opening his metal closet door in the next room, and I was looking into that room at the red-orange carpeting. Before I was fully awake I had received the sound stimulus but I had built a world out of it that most of us would not regard as real. (The experience of speeding over Mars was quite real, even if most humans would have a more accurate representation of that auditory stimulus.) So, a better way of saying "how do I know 'this' is reality, rather than another dream, or a simulation?" is to ask "how do I know I am perceiving "true" stimuli, without mapping them unnecessarily onto internal stimuli, giving me as accurate and un-contorted a view of the world as possible?"

And indeed in certain ways, we certainly are dreaming, in the sense of injecting internal stimuli and filtering external stimuli through them. (Notably, it is possible to view schizophrenics as people who experience dreams even while awake and filter their perceptions accordingly.) First and most obviously, because our sense organs are limited in what they can detect, we're obtaining only a slice of possible data. Second, the world we knit together is the result of binding of sensory attributes into object/events, as well as pattern recognition. The limitations of our nervous systems, and the associations we are able to make, profoundly influence the representation we build of the world we're perceiving.

Third, and most significantly, a large part of our experience is non-representational: emotions, pleasure and pain do not exist outside of nervous systems, or rather the events to which those experiences correspond are almost entirely contained within nervous systems. Yes, to be precise the experience of light does not exist until the triggering of a cascade of electrochemical events by radiation incident on pigments in retinal cells; but light, which is what is represented in our experience, exists traveling across the universe. Pain and happiness do not. These are internal stimuli that add a non-representational layer to reality, even more certainly than my dream of the Mars overflight.

A good working definition of a simulation as it is commonly understood is when the majority of one's external stimuli are supplied deliberately by another intelligence to produce experiences that do not correlate to physical reality external to the nervous system (or computational equivalent). This avoids taking a position on AI; the sims may or may not be entities separate from the computation. I.e., you might be in sensory deprivation tank like Neo, or you might be a computer program. The question of reality versus dreams or simulations is not one of discrete "levels" as we've come to think of it in popular culture. It is rather a question about how we know our experiences correspond in some consistent way with events separate from our nervous systems.

Looking for Neurological Differences Between Nouns and Verbs

Just ran across this poster presented at the Organizing for Brain Mapping's Annual Meeting in 2004. Sahin, Halgren, Ubert, Dale, Schomer, Wu and Pinker looked at the fMRI and EEG changes associated with a number of language tasks, and one of the questions they asked was whether activation characteristics were different for nouns and verbs. This study did not find that they were.

In my sketch of a neurolinguistic theory, verbs are first order modifiers and are distinct from adjectives in that they mediate properties and relationships between nouns. (In this sense, intransitive verbs are more similar to adjectives than to transitive verbs.) I also postulate that nouns and first order modifiers should have identifiably different neural correlates. I have not yet completed a literature search (obviously, if I'm citing posters from 2004.) However, even if such different neural correlates obtain, then I think it the task design here was not necessarily adequate to capture such differences, because the participants were asked to morphologically modify the nouns and verbs in isolation, rather than in situ, in grammatical relation to each other.

Another interesting experiment would be to give the participants nonsense words and new affixing rules (i.e. not revealing the part of speech of the nonsense word, i.e. ("if the word has a t in it, add -pex to the end, otherwise, add -peg"), and look for any difference relative to neural correlates of morphological tasks done in real words.

Strong AI, Weak AI, and Talmudic AI

Yale Computer scientist David Gelernter argues here that Judaic dialectic tradition will help us to reason our way through the moral morass of the first truly intelligent machine. I had first written this off as an article in the genre of "interesting collision of worldviews". But in the near future the cognitive science debates we're having today will seem luxuriously academic and unhurried, because for several reasons involving computing and neuroscience they will soon be more than intriguingly difficult questions. Even if we can all agree that suffering must be the basis of morality, we will need a way to know that, on that basis, it's not okay to disassemble someone in a coma, but it is okay to disassemble a machine that can argue for its own self-preservation.

John Searle Must Be Spamming Me

Because with all the comment-spam, the waiting-to-be-moderated comments list looks like a Chinese chat-room. I have yet to see any Hindi. And anyway I'm sure the machine producing the spam doesn't understand the symbols.

Reflections on Wigner 1: Humility in Pattern Recognition - Mathematics as a Special Case

It's often asked how natural selection could have produced something like the mathematical ability of modern humans. Why can an ape, designed to mate, fight, hunt and run on a savanna, and perceive things that occur on a time scale of seconds to minutes and a size scale of a centimeter to a few hundred meters, even partly understand quarks and galaxies? Implicit in this statement is an admiration for that ability, and the power of mathematics, as well as an assumption held by physicists that should not be surprising.

The physicists' assumption is that the whole of nature, or at least the important parts of it, can be described by mathematics. In "The Unreasonable Effectiveness of Mathematics in the Natural Sciences", Wigner observes "Galileo's restriction of his observations to relatively heavy bodies was the most important step in this regard. Again, it is true that if there were no phenomena which are independent of all but a manageably small set of conditions, physics would be impossible." Another way of saying this is that those regular relationships in nature most easily recognizable by our nervous systems are those parts of nature which we are most likely to notice first; seasonal agriculture preceded gravitation for this reason. But there is a circular, self-selection issue here about the interesting correspondence between the empirical behavior of nature and the mathematical relationships humans are capable of understanding, which is that:

a) humans can understand math.

b) What we have most clearly and exactly understood of nature so far (physics) employs math

c) Therefore, math uniquely and accurate describes nature.

Point b may be true only because our limited pattern recognition ability (even including infinitely recursive propositional thinking like math within that term) only allows us to recognize a certain limited group of relationships among all possible relationships in nature. In other words, of course we've discovered physics because those relationships are the ones we can most easily recognize! It's as if someone with a ruler goes around measuring things, and at the end of the day looks at the data she's collected and is amazed that it was exactly the kind of data you can collect with a ruler.

This discussion is far from an attack on usefulness of mathematics; if you have a model that worked in the past, bet on it working in the future, and the fact that not everything in the universe is yet shown to be predictable by mathematical relationships is certainly not cause to say "We've been at it in earnest for a few centuries and haven't shown how math predicts everything; time to quit." But it also certainly isn't time to say that math can show or has shown everything important, and the rest is necessarily detail. The whole endeavor of truth-seeking I think has at least something to do with decreasing suffering and increasing happiness, both very real parts of nature, and as yet there are very few mathematical relationships concerning them. I look forward to the day that such relationships are shown, but we cannot assume that they exist, or that if they don't, suffering is unimportant.

One problem is that if indeed there are relationships in nature un-graspable by human cognition or mathematics (and note that I've made no argument as to whether those two things are the same), how could we know? It would just look like noise, and we couldn't tell if a knowable relationship was there and had yet to be pulled out, or there was nothing to know (or knowable). We might at least know whether such unknowable information, or "detail", could exist, if we had some proof within our propositional system that there are statements which are true but cannot be deduced from the system. And we have just such a proof.

If we regard mathematics as a formalist does, that math is a trick of our neurology that corresponds usefully enough to nature, the question of why math is useful at all becomes even more important. But if we inject a little humility into our celebration of our own propositional cleverness, the matter seems less pressing.

We have no reason to believe that the total space of comprehensible relationships in nature is not far, far larger than what is encompassed by "mathematics", even in math's fullest extension. If this is the case, it is easier to see how our mathematical ability is a side effect of natural selection and the nervous system it created. By giving us a larger working memory than our fellow species along with some ability to assign symbols arbitrarily, that nervous system does allows us to use propositional thinking to see nature beyond the limitations of our senses - but just barely.

In this view, we can perceive just the barest "extra" layer of nature beyond what our immediate senses do, and mathematics seems far less surprising or miraculous. There is still reason enough to investigate math's unreasonable effectiveness but we shouldn't insist on being shocked that it could have been produced by the hit-and-miss kluges of evolution. But I've made another circular assumption here, which is:

a) evolution proceeds according to natural law

b) evolution will therefore favor replicators that have some appreciatiof some of those natural laws, and modify their behavior accordingly

c) therefore, our ability to perceive the laws that have impacted our own survival, and maybe a few extra ones of the same form, should be expected


There are two mysteries then: first, that any type of regular pattern exists in nature, and second, that we are able to apprehend these patterns, particularly through mathematics. The second mystery probably disappears, seeming special only because of the likely incompleteness of math as a tool to describe nature, math's special case as a method of perception stemming from our own neurology, and the circular basis of our wonder at this as-yet early phase in our use of it. But the first question, of how or why even partly regular relationships appear to exist at all in nature, regardless of how we perceive them, remains untouched by this essay.

In the Land of the Blind

...the one-eyed man must remember the majority is always sane. The Country of the Blind by H.G. Wells explores how an entirely blind civilization might view the universe, and how sighted people might interact with them. The Churchlands' infra-people, while argumentative, seem quite diplomatic by comparison.

Redwoods Aren't That Ancient or Special

Redwood Preserve in the Oakland Hills.

It's a common claim on informational signs in California parks that "redwoods were around at the time of the dinosaurs", or some such statement. While they're certainly amazing organisms, are these really tree-coelacanths?

Timetree consistently gives a divergence of trees in the order Cupressaceae (redwoods, junipers, various cypresses) at 80 MYA. We know from well-preserved fossilized trees that there were trees growing in the late Cretaceous that looked like modern redwoods, in the same place that modern redwoods grow. (This particular petrified forest near Napa, California is by far the most amazing petrified forest I've ever seen. I had to touch the trees to convince myself they're stone and not wood.)

Because fossilized "redwoods" date back to just after the putative divergence time, it's likely that modern redwoods are merely the more-ancestral-appearing descendants (relative to junipers and cypresses) of the these ancestral trees. Although the size and bark of the fossilized trees look similar to the redwoods today, that certainly doesn't tell the whole story about them, although barring miraculously preserved 65-million-year old Cretaceous tree DNA, that's about all we'll get. Consequently those old trees would more appropriately be called ancestral cypresses. Maybe the Ancient Giant Cypress?

Either way, redwoods are still pretty special, although not in the way that their chromosomes somehow resisted entropy for 65 million years.