# Is it possible to alternate the law of mathematics?

I am freelance writer. Recently I have been planning a science fiction - just planning, nothing solid yet - and I was wondering would it be possible for some other universes that have different set of mathematical laws? By alternative mathematical laws, I mean $1+2\ne 2+1$ or $1\times2\ne2\times1$, or that the prime number 3 is no longer a prime in other universe, that kind of stuff. To push things further, I am imaging that a horrendously-advanced alien civilization maybe able to, by some mysterious method, change the mathematical laws here on earth, so as to disarm our spaceships and conquer our world.

I have read some popular science books, and was informed that we could have different physical laws in other universe, if the other universe exists. This is the motivation behind my (naive) question. I think, from a writer's prospective, I may have more freedom in creating a plot, well, at least I myself is the rule-maker.

My major was biology, so I haven't really learned any maths at all, plus the fact that I left college some twenty years ago. I can merely make sure I wasn't in any debt using my math skills, so I hope my questions aren't bad or stupid.

Sorry for these irrelevant details, I repeat my two questions below:

• Is it possible to have different mathematical laws in other universe?
• Is it possible for some aliens to alter the mathematical laws in our universe?

EDIT I'd like to mention that I have read the novel "Contact" by Carl Sagan. I was truly amazed that those aliens sent prime numbers to Ellie, who then be able to make the contact happens. But then I wonder, what if those aliens somehow do not have the same prime number we have on earth? This is just my random thought.

EDIT 2 @Robert Mastragostino made a good point in the comment. I think what I am asking is that, could the deductive reasoning, which I suppose mathematics is mostly based on, be violated? That is, if those aliens are powerful enough, we no longer have $1+1=2$ on earth but $1+1=3$?

EDIT 3 After reading all your comments so far, I now start to think that I may have asked the wrong question. I used to think that math is "superior" than physics, as being convinced by a comic. The analogy by Ryan showed me that math is somewhat like a language, and I think that, well, what's the big deal about changing a language? It appears that physics is still all that matters if you want to win an alien war. Let me know if I am wrong (again).

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You might be amused by Greg Egan's short story "Luminous", which treats some of these themes as carefully and rigorously as seems possible. (Summary and reviews) –  MJD Aug 28 '13 at 17:55
My view is that mathematics is immutable throughout the universe and indeed throughout all possible universes – because mathematics is unphysical. Thus, even if you could alter the laws of mathematics, nothing would happen in the physical world! –  Zhen Lin Aug 28 '13 at 17:59
en.wikipedia.org/wiki/Flatland –  Amzoti Aug 28 '13 at 18:00
The idea of "mathematical laws" isn't too clear to begin with. If I come up with a new type of number system I don't call it a new "mathematical law". It just takes a logical place alongside the old ones, without really being considered as part of "another universe's mathematics". Systems with contradictory axioms live happily together in math as alternatives, which is a bit different from the other sciences that cleanly separate "real" from "hypothetical". You might go for a universe that uses number systems differently? e.g. counting isn't done with naturals, but modular arithmetic. –  Robert Mastragostino Aug 28 '13 at 18:15
@dfeuer I'm not sure I follow. The idea was that mathematics itself was set up from the beginning with coded messages (such as the circle in $\pi$). The message sent by "the others" was not embedded in a constant, was pulses that came with too much regularity to be produced by natural causes. And the way Sagan imagined the message itself was carried out is based on a protocol that has a serious theoretical background (lincos), see here. –  Andres Caicedo Aug 28 '13 at 18:48

As other commenters have said, you are probably going to get more milage by looking for alternative (local?) spacetimes that would allow the aliens to use their own laws of physics. The "laws" of mathematics can be thought of as a language, in the sense that if you change them* then you wouldn't necessarily have any effect on the universe.

(*And it's not clear what exactly this would mean: mathematics as usually studied is a form of an axiom system called ZFC, and people experiment often with axiom systems that are weaker than, stronger than, or inconsistent with ZFC.)

However, here is an excerpt from the Wikipedia page on hpyercomputation which seems like it would be of interest to you. [Citations have been removed]

According to a 1992 paper, a computer operating in a Malament-Hogarth spacetime or in orbit around a rotating black hole could theoretically perform non-Turing computations.

So these hypercomputations might be available to anyone who can generate (and mitigate the effects of) a black hole.

A super-Turing machine would definitely be able to solve the classical halting problem, that is, the halting problem for Turing machines. The explanation is given very briefly in another Wikpedia page. However, my intuition is that it would be unlikely to be able to solve the halting problem that they would be concerned with, the halting problem for their name brand of super-Turing machines.

I would be careful about throwing Gödel around, however. It might be that when you get down to the very low-level nuts and bolts that there is some finiteness-of-proofs assumption. If that were the case then you might be able to get around those pesky incompleteness theorems (well, the classical incompleteness theorems, at least…). However the way that it's been described to me has made it seem like you could very easily run into a classical-Gödel problem regardless of what sort of infinities you have access to.

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Can I interpret your last paragraph that, any computer-like things are bounded to have some computation limit? –  Mikael Aug 28 '13 at 19:48
Yes, it is well known and formalized in computer science. A simple diagonalization shows that you can't have a computer (universal machine) and an halting solver in the same scope. It is linked to the absurdity of the set of all sets. –  Xoff Aug 28 '13 at 19:51
I'm sure that I will say something very strange to you, but computing power is like ordinals : you can always define a theoretical computer that is much more powerful than another theoretical system. But even if you consider an infinite series of such systems $s_0<s_1<s_2<\dots$, there will be another system $s_\omega$ that will be more powerful than all of them. But as all other systems, there will be another system more powerful than $s_\omega$. No system can "do everything" without being inconsistent. –  Xoff Aug 28 '13 at 20:01
@Xoff: so can I say that "there is always a better computer" and "no computer can do everything"? –  Mikael Aug 28 '13 at 20:06
yes, both sentences are in fact the same. But you must understand this is purely speculative. Because, what we can do in a mathematical scope is very different of what we can do in reality : to build those super computers, we need to find new physical laws that we don't know yet. In mathematics, we have no such limits. So practically, all computers on earth have the same limits, and we just improve the speed a little bit, but not what they can really do. If quantum computers work as expected, we'll be able to answer much more rapidly to some answers, but we won't be able to solve new problems. –  Xoff Aug 28 '13 at 20:13

A "horrendously-advanced alien civilization maybe able to" -carry their physical laws with them while being in our universe -in a local periphery of their spaceships. What better "shield" could there be? Since what you intent to write seems like a space-opera with evil aliens, this plot device will help you make their spaceships almost invincible - at least for long enough in your book to build up drama, as well as to narrate the heroic mission to uncover either their laws, or a way to map their laws to ours, or a way to just break this shield (and then imagine what would happen to them when exposed to the laws of our universe). Since this forum seems to have given you enough good ideas, I believe that it is appropriate that you commit publicly that, the final version of your book will contain at least some pages of mathematical and physics philosophy, preferably together with some mathematical symbols - and that you will guard these pages with your life against any publisher that will try to delete them arguing that they will alienate your potential readers.:)

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Ah, that was the plan until now :P –  Mikael Aug 28 '13 at 19:17
Well, Mikael, it's not only evil aliens that have hidden agendas... –  Alecos Papadopoulos Aug 28 '13 at 19:24

As others have already mentioned, it doesn't make much sense to "alter" mathematics. You can however invent "new" mathematics, by starting from a different set of axioms.

If what you are looking for is a mathematical system which seems totally counterintuitive, I would recommend you look into the p-adic numbers. In basic arithmetic we can make statements like "$9$ is closer to $10$ than it is to $27$." When dealing with p-adic numbers, however, $9$ would be closer to $27$ since they both contain a factor of $3^2$. Such a strange notion of distance would throw euclidean distance straight out the window.

As for your second question, I don't think there is a definitive answer. It doesn't make much sense to say that the universe is governed by mathematical laws in the first place. Rather, we have found mathematical laws which model it very well. For an alien species to change the "math" of the universe is equivalent to them changing the very laws of the universe itself. But there is no reason for this to limit you - the genre of sci-fi isn't usually constrained to reality, so I don't see a reason why a fictional alien species couldn't alter mathematical laws while keeping the laws of physics intact.

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I thought physics must change if mathematics changes, so it is not necessarily true? Interesting... –  Mikael Aug 28 '13 at 18:59
In your situation, it is best to think of math as a language which is used to describe various physical phenomena. You can't change the language itself. But if the rules of the universe became really whacky, we would have to start using different words in our language to describe it. –  Ryan Aug 28 '13 at 19:04
So math is like French if I was born in France, but I need to learn German if I want to do business with German? –  Mikael Aug 28 '13 at 19:19
Yes, I think that is a fair analogy. –  Ryan Aug 28 '13 at 19:26