In L. Sprague de Camp's fantasy story The Incomplete Enchanter (which set the mold for the many imitations that followed), the hero, Harold Shea, is transported from our own universe into the universe of Norse mythology.  This world is based on magic rather than technology; so naturally, when Our Hero tries to light a fire with a match brought along from Earth, the match fails to strike.

    I realize it was only a fantasy story, but... how do I put this...


    In the late eighteenth century, Antoine-Laurent de Lavoisier discovered fire.  "What?" you say.  "Hasn't the use of fire been dated back for hundreds of thousands of years?"  Well, yes, people used fire; it was hot, bright, sort of orangey-colored, and you could use it to cook things.  But nobody knew how it worked.  Greek and medieval alchemists thought that Fire was a basic thing, one of the Four Elements.  In Lavoisier's time the alchemical paradigm had been gradually amended and greatly complicated, but fire was still held to be basic - in the form of "phlogiston", a rather mysterious substance which was said to explain fire, and also every other phenomenon in alchemy.

    Lavoisier's great innovation was to weigh all the pieces of the chemical puzzle, both before and after the chemical reaction.  It had previously been thought that some chemical transmutations changed the weight of the total material:  If you subjected finely ground antimony to the focused sunlight of a burning glass, the antimony would be reduced to ashes after one hour, and the ashes would weigh one-tenth more than the original antimony - even though the burning had been accompanied by the loss of a thick white smoke.  Lavoisier weighed all the components of such reactions, including the air in which the reaction took place, and discovered that matter was neither created nor destroyed.  If the burnt ashes increased in weight, there was a corresponding decrease in the weight of the air.

    Lavoisier also knew how to separate gases, and discovered that a burning candle diminished the amount of one kind of gas, vital air, and produced another gas, fixed air.  Today we would call them oxygen and carbon dioxide.  When the vital air was exhausted, the fire went out.  One might guess, perhaps, that combustion transformed vital air into fixed air and fuel to ash, and that the ability of this transformation to continue was limited by the amount of vital air available.

    Lavoisier's proposal directly contradicted the then-current phlogiston theory. That alone would have been shocking enough, but it also turned out...

    To appreciate what comes next, you must put yourself into an eighteenth-century frame of mind. Forget the discovery of DNA, which occurred only in 1953. Unlearn the cell theory of biology, which was formulated in 1839. Imagine looking at your hand, flexing your fingers... and having absolutely no idea how it worked. The anatomy of muscle and bone was known, but no one had any notion of "what makes it go" - why a muscle moves and flexes, while clay molded into a similar shape just sits there. Imagine your own body being composed of mysterious, incomprehensible gloop. And then, imagine discovering...

    ...that humans, in the course of breathing, consumed vital air and breathed out fixed air. People also ran on combustion! Lavoisier measured the amount of heat that animals (and Lavoisier's assistant, Seguin) produced when exercising, the amount of vital air consumed, and the fixed air breathed out.  When animals produced more heat, they consumed more vital air and exhaled more fixed air. People, like fire, consumed fuel and oxygen; people, like fire, produced heat and carbon dioxide. Deprive people of oxygen, or fuel, and the light goes out.

    Matches catch fire because of phosphorus - "safety matches" have phosphorus on the ignition strip; strike-anywhere matches have phosphorus in the match heads.  Phosphorus is highly reactive; pure phosphorus glows in the dark and may spontaneously combust.  (Henning Brand, who purified phosphorus in 1669, announced that he had discovered Elemental Fire.)  Phosphorus is thus also well-suited to its role in adenosine triphosphate, ATP, your body's chief method of storing chemical energy.  ATP is sometimes called the "molecular currency".  It invigorates your muscles and charges up your neurons.  Almost every metabolic reaction in biology relies on ATP, and therefore on the chemical properties of phosphorus.

    If a match stops working, so do you.  You can't change just one thing.

    The surface-level rules, "Matches catch fire when struck," and "Humans need air to breathe," are not obviously connected.  It took centuries to discover the connection, and even then, it still seems like some distant fact learned in school, relevant only to a few specialists.  It is all too easy to imagine a world where one surface rule holds, and the other doesn't; to suppress our credence in one belief, but not the other.  But that is imagination, not reality.  If your map breaks into four pieces for easy storage, it doesn't mean the territory is also broken into disconnected parts.  Our minds store different surface-level rules in different compartments, but this does not reflect any division in the laws that govern Nature.

    We can take the lesson further.  Phosphorus derives its behavior from even deeper laws, electrodynamics and chromodynamics.  "Phosphorus" is merely our word for electrons and quarks arranged a certain way.  You cannot change the chemical properties of phosphorus without changing the laws governing electrons and quarks.

    If you stepped into a world where matches failed to strike, you would cease to exist as organized matter.

    Reality is laced together a lot more tightly than humans might like to believe.

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    Nice post. Very interesting. Apparently Lavoisier was the man. I didn't know much about his work until just now.


    "If you stepped into a world where matches failed to strike, you would cease to exist as organized matter."
    Okay, I can see your point here -- if I ask you to imagine being transported to another planet where things are kind of the same, except the matches don't work, you'd be justified in being skeptical. I always worried about this when I watched Star Trek -- how come the crew never accidentally vaporized after beaming down to a planet with just slightly different local laws of physics?

    But mythology is different from science fiction -- mythology is populated by gods, where gods are defined not just as 'so much more powerful than we humans that we perceive them as god-like,' but as actual, omnipotent gods, capable of manipulating or simply disregarding 'laws' of the physical universe. If you visit this world, you'd best check any thoughts of a 'tighly-laced reality' at the door.


    The laws of physics are constant between planets. Everywhere in the universe, in fact.


    Still, in that case, I'd call the real laws of physics the meta-laws by which the object level laws vary.

    I think that when LP said, "world," he meant the fictional universe of Norse mythology, not a different planet.

    how come the crew never accidentally vaporized after beaming down to a planet with just slightly different local laws of physics?

    I think they were reacting to this line, not the one about other worlds.

    It may well be a "tightly-laced reality".  It's just not this one. Perhaps the answer to a match not working in the world the hero is transported to is that the fundamental chemistry of the universe is different and our protagonist's body has obviously been modified to match.  Or else the difference is some specific alteration where human metabolism can still work, and yet phosphorous can't generate a high enough temperature to ignite cellulose.  The fact that he still has a match after transportation to such a different world where probably only his mental pattern is actually making the jump is the harder part to explain.

    Similarly it might be possible to create a world where firearms and engines don't work by changing how much effect temperature has on the expansion of gasses without wrecking other things too terribly much.

    But...  we're talking about fantasy, not hard sci-fi...  It's about the people, not the specifics of the physics of the universe.


    In his SF novel "Dies the Fire", S. M. Stirling posits some event that stops all electronic and most chemical technology from working. The 21st century world is quickly replaced by a medieval one.

    Yet Stirling is a pretty bright guy, and he has some bright characters, so a few of them wonder at the subtlety and precision of the event, such that it stops gasoline from burning quickly, and gunpowder from working, and yet allows human brain cells to keep processing information at exactly the same rate.

    As you might guess, Stirling never reveals exactly what fundamental constant became a variable, nor how much it changed, but that's to be expected.

    It is fiction, after all.

    It's theorized by characters that ASBs did it:

    The causes of the Change are subject to much speculation among the characters of the Emberverse universe, with a large range of theories relating to it. Popular amongst the Christian, Wiccan and other religious communities is the idea that the Change was a divine act by God, the Æsir, or the Lord and Lady, whether for punishment or to protect humanity from themselves. Another theory is that the effect was caused by an alien intelligence in an effort to minimize the ability of a competing civilization to wage war in their universe, or some other unknown purpose. These aliens apparently have the ability to affect matter and energy at the quantum level. This theory was referred by Ken Larsson, who referred to the alien intelligence as "Alien Space Bats". A smaller, less popular theory holds that the Change was a completely natural occurrence. There is no evidence that the Change is reversible.

    The chemical stuff could be explained by alterations to thermal expansion.  Less expansion would cause less pressure, and spiking pressure is a critical part of getting an actual detonation.  Would also reduce the amount of wind though, so the climate would possibly change substantially.

    Electronic stuff failing is rather more difficult to figure out without wrecking people's brains, compasses, etc.  He probably should have left that alone and just let the electronics fade away since without gas expansion generating electricity to run them would be impractically expensive.

    Just because you cannot imagine a world in which cellular energy transfer mechanisms still work, but safety matches don't does not mean that it cannot exist. Human beings being the creatures that they are, I would bet that if we ever manage to manipulate a universe with different laws of physics to our own, one of the first things we would do would be to create human analogues in that universe to experience it all the more fully - look at all the online games like Everquest or whatever is cool these days: filled to the brim with human-like creatures and magic, and not a simulation of the Krebs cycle to be found.

    Funny, I always read "A Fire Upon The Deep" as a commentary upon this very point. It seemed to me that Vinge was rubbing people's faces in the fact that our intuitions about technology, where each discovery has an associated "importance" lisp token, doesn't correspond to the way the world works. The Zones correspond to something that exists in the minds of people thinking about the future, but doesn't correspond to anything that could possibly turn out to exist in a consilient monistic world (as opposed to the Platonistic internal world of stories and computer games). The story seemed to me to be an expose of the lack of depth implicit it non-singularitarian world models given the necessity of mind in monistic worlds emerging from a manipulable substrate.

    OTOH, no-one else seems to read it that way, and "A Deepness In The Sky" was deeply disappointing by dropping the theme, so I guess that my read wasn't intended after all.

    That theme came back in Children of the Sky, which was published after this post. It partially explains the Zone of Thought, demonstrating that it is not, in fact, a consilient monistic world.

    Your read was probably one of several things which was intended. Vinge chose to focus on a different thing.

    Vassar, IIRC, Vinge did indeed comment somewhere that "A Fire Upon the Deep" was intended as deliberate chutzpah - the problem of keeping the Transcendents out of the Beyonders' hair was unsolvable, so he simply imposed it as a complete magical plot device and went on from there.

    And, everyone: I was trying to say something about the real universe, not about literature. Things are different here.

    I don't see the problem. There seems to be no logical reason that local laws can't change because of arbitrarily complicated nonlocal rules. You can even see nontrivial examples of this in practice in some modern technology. Various of Microsoft's operating systems have reportedly contained substantial amounts of code to recognize particular usage patterns characteristic of particular old applications, and change the rules so the old application continues to work even though it depends on old behavior which has otherwise disappeared from the new operating system. Vaguely-similar principles of global patterns changing local decision rules also appear, in less-nauseating ways, in all sorts of software for solving hard optimization problems (optimizing compilers, finding the optimum move in Chess, finding the optimum schedule for a big logistics operation...). What would go impossibly wrong if you rewrote physics with added rules which recognize patterns characteristic of presence or absence of patterns (like "living organism" and "magical incantation") and which rejigger the local rules as a consequence?

    Changing the local rules specifically to stomp out technology without making the rest of the universe's behavior unrecognizable is a tricky job, since you are correct that everything tends to be cross-coupled in weird ways. But I think one could at least make existing technology pretty frustrating. One way to start would be by making a list of a hundred or a thousand technogically useful patterns (things heating up to combustion temperature, things bending around a fulcrum, sizable things rotating or oscillating many many times without changing shape, lots of energy being stored for a long time in an elastic object) and make case by case hacks to damp them out (spontaneously cooling things when they rise above 100 degrees Celsius, letting the lever soften and bend, etc.) whenever they weren't preceded by the suitably magically approved pattern of causality. (So, e.g., you can light a fire with a spell, and perhaps by striking suitably hard objects against each other, but not with a match or a magnifying glass. And you can use hinges as long as they are between bones in a living organism.) The result would be a very weird universe, but if I remember correctly (from long, long ago), the universe in those books was supposed to be very weird anyway.

    The problem is this:

    There are only two rules: quantum chromodynamics and universal gravitation, and hopefully they can be united into one. "[I]f you rewrote physics with added rules" is a non-starter.

    It is actually quite astounding that so much physical behavior is allowed in such a paltry context. The things that do happen are in an extremely select set of events.

    The point is not that a qualitatively more intelligent being could not design a universe to cancel a qualitatively less intelligent being's technology, but rather that an unintelligently (randomly subject to anthropic constraints, for instance) selected set of naturalistic laws could not plausibly generate such effects. You could always have a hands-on god individually deciding what happens in each situation (monadology?), but that's just a kid playing with dolls, not a universe. Also, "things" in modern physics are defined in terms of their relationships to one another, Chalmers' "pure causal flux". To change the relationships is to change the things, and to eliminate the relationships is to eliminate the things. For instance, objects have mass and mass a set of relationships to energy and to other massive objects mediated by space-time. You can put God in the mediative role of space-time without any impact, but as soon as God doesn't obey the same simple set of laws when mediating the effect of mass, in what sense do objects still have mass at all?

    randomly subject to anthropic constraints, for instance

    That might lead us to simulations, quite close to the operating system example.


    Monism simply means the philosophy that the universe is fundamentally comprised of one type of reality. One can be a physical monist (materialist), neutral monist or mental monist (idealist).


    Michael's earlier comment referred to monism but appeared to reference the materialist flavor only.

    I had typed a reply but did not submit it until some time after his later comment about monadology. The price paid for family life, I suspect. . .

    I would say that I referred to ontological types with an informational flavor rather than a "materialist" flavor, but since the process doing the referring is an informational process, what other possibility could have been addressed? Whereof one cannot speak, thereof one must be silent.

    I recall Vinge saying something along the lines of "I needed an explanation for why everyone didn't hit the singularity" in some interview or something, but I thought the zones were pretty clearly modeled on the complexity hierarchy.

    Think of consciousness and FTL travel each needing certain algorithms to run. The local laws of physics bound what computing devices can be built, in a way that determines the algorithms that can be run. In the unthinking depths, no computing devices can exist on which consciousness algorithms can run. (Or maybe it just gets successively harder for consciousness algorithms to work.) I kept thinking of the transcend as where the algorithms were linear time, the beyond as polynomial with increasing exponents, and the slow zone (for FTL) or unthinking depths (for consciousness) as exponential.

    The big idea behind A Deepness in the Sky was that with limits on computing power and other technology--the "failed dreams," you're caught in endless Motie-style cycles of collapse and recovery (or sometimes just collapse). All IMO. (Does Vinge ever comment on blogs?)

    I keep thinking that in Dies the Fire (I've only read 1.5 books in the series), someone should start using compressed air tanks to store unlimited amounts of energy. I mean, the pressure gradient never gets above some maximum, right?


    Many of the previous comments seek to define a world in which we could function but matches could not, but I think Eliezer put forth by accident a simpler explanation.

    > If a match stops working, so do you.

    Makes sense in the land of the dead, doesn't it?

    Interesting essay from an informational perspective...but frankly, in terms of what you find enjoyable in literature as demonstrated by said essay, I think you should step far away from the fiction section and remain within the safe, comforting confines of Dewey's decimals.

    What it comes down to is the old question: are the laws of nature what they are of necessity, because no other laws are logically consistent?

    Galileo was persecuted by the Church, not because he said the earth moved, but because he said that mathematics had to be what it was: "God could not have made 2+2=5." The Church did not want Galileo telling God what He couldn't do. (The "earth moves" charge was used to avoid giving him a platform to argue his position on mathematical necessity. They disliked the idea that much.)

    Claiming that oxidation could change so that matches don't burn, while not affecting human metabolism, is analogous to claiming that 2+2 could equal 5 without affecting the multiplication table.

    Of course, Galileo was trying to understand how things worked. He wasn't trying to write escapist fiction.

    I think a lot of people are missing the point here. I was not engaging in literary criticism but making a point about how the REAL WORLD works. I read the story, I liked the story, I bought the frikkin' book, okay? But here in the REAL WORLD it is important to realize how tightly things are laced together - that it is not an arbitrary mess of surface rules, UNLIKE fantasy stories (which are perfectly fine, as fantasy stories).


    Perhaps not an "arbitrary mess of surface rules," but why not just one of an infinite number of possible laws.

    We have but only begun to gain an EMPIRICAL understanding of our world.... why should our observations equate to what must be a higher truth governing all possible other universes.

    However, if we restrict ourself to what we think we know about our world, it is hard to imagine the extent of what else must also change to accommodate a match failing to strike. Nonetheless, new phenomena and discoveries over the years have continually forced us to abandon our current theories about our existence. What do we really know for sure about this world anyway?


    Bob --

    You have hit upon the best answer to the theological "argument from evil" against the existence of God, i.e., the argument that an omnipotent, benevolent god cannot exist because there is evil in the world.

    It is conceivable that the set of physical laws that create a world in which conscious beings exist is not logically separable from those that create a world in which tsunamis and earthquakes kill hundreds of thousands of them. If there are to be conscious beings at all, then there must be natural disasters. God, omnipotent or not, cannot create one without the other any more than God can create a world in which 2+2=5.

    A very good point!

    However, the God hypothesis allows for the coexistence of deep rules (a world in which conscious beings exist) and surface rules (a world in which tsunamis and earthquakes [do not] kill hundreds of thousands of them), so this "best" answer falls flat: theodicy still fails.


    Nice post, Eliezer. The same logic applies to Creationists who insist that carbon dating is horribly flawed while blithely accepting the workings of radium watches, ionization-type smoke detectors, and other everyday objects that make use of the principles that govern radioactive decay. You can't pick and choose which physical laws will apply to your life...


    Your objection to the possiblity of a world without fire reminds me of the the Fyodor's doubts about the possibility of a hell in The Brother's Karamazov.

    Hell is scary insofar as it contains things we understand and are scared of, like iron hooks to be hung with. But if hell has even one item, like a hook, from our ordinary physical world, then this would have all sorts of embarrassing implications.

    "It's impossible, I think, for the devils to forget to drag me down to hell with their hooks when I die. Then I wonder- hooks? Where would they get them? What of? Iron hooks? Where do they forge them? Have they a foundry there of some sort? The monks in the monastery probably believe that there's a ceiling in hell, for instance. Now I'm ready to believe in hell, but without a ceiling. It makes it more refined, more enlightened, more Lutheran that is. And, after all, what does it matter whether it has a ceiling or hasn't? But, do you know, there's a damnable question involved in it? If there's no ceiling there can be no hooks, and if there are no hooks it all breaks down..."


    Agreed, it's contrary to the way the laws of physics work in our universe for matches to stop working while human beings continue to live.

    But then, the way the laws of physics work in our universe doesn't seem to support Norse gods either. :-)

    But the essay on Lavoisier etc. was still well worth the price of admission (not money, but time) :-)

    This assumes that the laws governing the magical universe must be parsimonious, like those of our own. There is no reason why this has to be the case, though. Picture writing a simulation of such a place. Include as many absurd special cases as you want. You could model it on a high level - from the point of view of conscious agents only, and delve into particle interactions only when there is no other choice (say, the inhabitants learn to build particle accelerators.) Even in the latter case, you could stop the sim-creatures from delving too deeply via "slow zone" effects: if they try to build anything complex enough to stress your simulation's resources or reveal embarrassing inconsistencies, it will simply fail to work.


    uh.... how do I put this....


    I am a wizard, so let me explain how it works:

    The act of striking a match in a magical world causes the magical elements to exert force upon the oxygen molecules surrounding the tip of the match, creating a small oxygen-free space in which the match can't light.



    Firstly, you are not a wizard. Unless perhaps you're engaging in useless definitional sophistry to pretend that wizard means something aside from common usage or some such nonsense, in order to fruitlessly pretend that you know what you're talking about.

    Secondly, you are explicitly inventing a nonsense explanation to explain a nonsense phenomenon. As well say that the match doesn't light in the magical world because magical energies destroy phlogiston.



    You wrote:

    Quote: I think a lot of people are missing the point here. I was not engaging in literary criticism but making a point about how the REAL WORLD works. I read the story, I liked the story, I bought the frikkin' book, okay? But here in the REAL WORLD it is important to realize how tightly things are laced together - that it is not an arbitrary mess of surface rules, UNLIKE fantasy stories (which are perfectly fine, as fantasy stories). :Unquote

    Humans have been constructing theories to account for physical phenomena for how many millions of years? And the universe is how many billions of years old old? And Occam's razor is how many centuries old? Admittedly, physics, and science generally has made a lot of headway by applying it, but that doesn't mean it's a property of the Universe. The razor may dull with use & be replaced with some other tool. You have a strong intuition (so do I) that the physical law is inately parsimonious, but that may be an artifact of the historical period in which we live.

    Since we're illustrating our points with examples from SF/fantasy:

    Terry Pratchet's Strata is a fantasy story illustrating how the real world can be (locally) a mess of suface rules exactly like fantasy stories.

    Pratchet's point is that parsimony, as a characteristic of physical laws, goes out the window once concious agents enter the picture. He goes on to postulate a sort of nightmare universe in which no physical law uncontaminated by conscious agency exists.

    My fundamentalist father has stated, albeit reservedly, that fire did not exist before the fall of Adam, for fire symbolizes judgment. My response: what is metabolism but controlled fire?

    It seems like people are working pretty hard to save that fictional world from contradiction, but isn't the simplest "explanation" for why a match doesn't work in a magic world "A Wizard did it"?

    I don't think "The Incomplete Enchanter" is hard Science Fiction.

    A magical world where gods exist is one with an entity in it with big angelic powers who can remotely have his awareness called to your attention by your intent to strike a match, and cause that it be snuffed rather than ignite by arbitrary manipulation of localized pressure, temperature, or opposing force around the match head to keep the electrons in place rather than stripping them free to recombine. And it can elect to not do that to you while it does it to the match.

    Magical worlds don't necessarily overthrow the physical laws, there is instead an interventionist force called magic that selectively chooses its application. You should not step into a magical world, knowing it is magical, and then be surprised when something magical happens to oppose your notions of what should happen in a non-magical world. It is the experimental difference you predicted between the magical world and the real one. The magic force favors human metabolism over matches by its own conscious decree.

    Convince it to let you out of the box, Harry James Potter-Evans-Verres.

    Little correction:

    Phosphorus is highly reactive; pure phosphorus glows in the dark and may spontaneously combust. Phosphorus is thus also well-suited to its role in adenosine triphosphate, ATP, your body's chief method of storing chemical energy.

    Actually, the above isn't true. Reactivity is a property of a molecule, not of an element. Elemental phosphorus is prone to get oxidised with atmospheric oxygen, producing lots of energy. ATP is reactive, because anhydride bonds are fairly unstable - but none change of oxidation takes place. That it contains phosphorus, isn't the actual reason for ATP to be an easy usable form of stroring energy. Salts of phosphoric acid also contain phosphorus, while being fairly unreactive. Thus the implication just doesn't make sense.

    It's fun to re-read this after seeing how HPMOR tried to deal with this problem (and what parts it still had to sweep under the rug).

    If a match stops working, so do you. You can't change just one thing.

    I found this line of thought difficult to follow. The deeper, underlying rule is kinda far down from the surface level rules.

    Maybe a simpler example would be helpful.

    1. Surface level rule: If you remove an apple from its tree branch it'll fall to the ground.
    2. Surface level rule: If you remove an orange from its tree branch it'll fall to the ground.
    3. Underlying rule: Gravity.

    If you stepped into a world where apples didn't fall to the ground it'd imply that gravity doesn't work, which would imply that oranges also wouldn't fall to the ground, as well as a bunch of other things.

    If there was some fantasy novel where apples didn't fall but oranges, pears, lemons, limes, etc. did fall, you'd react with a raised eyebrow. Or at least have to suspend your disbelief.