The Simple-as-Possible Universe Hypothesis Friday, Jun 22 2007
anthropics 5:16 am
It seems that math may be unreasonably effective for understanding the universe. Complex phenomena, simple rules.
The universe may be simpler than it looks. It may in fact contain almost no information. Tegmark and other physicists argue that the universe is isomorphic to a mathematical structure and we are currently uncovering all the information content incrementally. In this view, our mathematics is a mathematical structure approximating another mathematical structure, rather than a mathematical structure approximating a physical structure.
So the universe could be a simple mathematical structure with self-similarity on all scales, like a fractal. In the abstract to an aforelinked paper, Tegmark writes, “In this paper, it is suggested that most of this information is merely apparent, as seen from our subjective viewpoints, and that the algorithmic information content of the universe as a whole is close to zero.” So the universe’s mathematical simplicity can be reconciled with its apparent complexity from our point of view.
Many physicsts believe all possible universes exist. According to the teleological-sounding but theoretically elegant anthropic principle, only those universes which permit conscious observers to exist are observable. If our universe is indeed quite simple, it surely cannot be too simple, otherwise it would lack conscious observers to experience it. It would make much more sense if it were as simple as possible but still complex enough to harbor consciousness.
I reached this idea on my own some time ago, and it seems that a few others have also discovered it independently. A search for “simplest possible universe” brings up a mailing list post by Fred Chen, a page on anthropics without an author indicated, and a book, Theory of Nothing, by Russell K. Standish, an associate professor with the math department at the University of New South Wales. German AI researcher Jürgen Schmidhuber also addresses the issue here.
Two begging questions seem to come out of this idea. The first is that there must exist some absolute criteria for the development of self-aware consciousness, and that these criteria have, self-evidently, been satisfied in this universe - but what are they? With a sample set of one, it’s hard to tell. The second question is, “is there an underlying mechanism with its own internal complexity that generates universes?” If all types of universe are realized an infinite number of times, then why is it any more likely for any given sentient being to be born into a simple universe?
June 22nd, 2007 at 6:01 am
If, as Tegmark’s hypothesis suggests, our universe is at its core simply a mathematical structure, this would seem to lend even more credence to Nick Bostrom’s argument that we are living inside a computer simulation.
June 22nd, 2007 at 6:21 am
I have long thought that Murphy’s Law rules the universe, and indeed that if there is ever a grand unified theory developed it will read very much like Murphy’s Law. I guess that would make the Big Bang the Giant Oops.
June 22nd, 2007 at 8:48 am
Couple of thoughts:
- while aesthetically pleasing, our Universe may not be the *simplest* possible. It just has to work well enough such that it can produce observers who can in turn speculate about how simple the Universe might actually be. I often use the genome analogy when thinking of the universe’s parameters (assuming the universe is a sort of self-replicative, iterative entity). There’s a lot of superfluous junk in our genome, why not also the universe? The space of all possible observer friendly universes may be larger than we think.
- given a ’simple’ universe (what Mark Walker has described as a ‘tic-tac-toe universe’ as opposed to a ‘chess universe’), the potential for radically advanced intelligent life may be more constrained and limited than what we have heretofore imagined. Our optimal future-state may be more straight-forward and practical than some of the more wild transhumanist visions. Moreover, there may be little point to ascribing deeper meaning or purpose to our presence here.
June 22nd, 2007 at 1:13 pm
Michael said: “why is it any more likely for any given sentient being to be born into a simple universe?”
I’ve had some thoughts about this one. First of all, when we say the universe is “simple”, we mean that, at first, it appears complex, and then upon closer examination there is a simple set of laws that can generate all or most of that complexity. Perhaps it is better to say that the universe is “compressible”. Another “compressible” universe would be something like wolfram’s rule 30:
http://en.wikipedia.org/wiki/Rule_30
Note that this rule produces lots and lots chaotic looking patterns, and if you didn’t know it was produced by a simple rule, you might call a “universe” generated by rule 30 a complicated universe. If you were a sentient being living inside a rule-30 universe, you might eventually discover that your universe has a great underlying simplicity!
I can think of a universe that is merely simple, without any apparent complexity. It would look just like a blank sheet of paper. I might call such a universe “boring”. Most of Wolfram’s cellular automata produce “boring” universes, you can see a list of them here:
http://www.wolframscience.com/nksonline/page-55
The third type of universe I can think of is a “random” universe - one where there each part is totally independent of every other part. This would look like the TV screen when you unplug the aerial.
Now, of the three types, “boring”, “compressible” and “random”, intelligent life can only exist in a compressible universe, that is a universe where there are underlying simplifications to be made. If there weren’t, then what good would intelligence be?
June 22nd, 2007 at 2:09 pm
Thanks for this post Michael.
I’ve always held that the universe is fractal-like and the complexity is simply a result of our individual limitations to comprehend the whole. I also liked Roko’s compressible analogy.
The other observation is the concept that there are causal elements (or rules) that contribute to the observable complexity directly or indirectly which may not be readily observable with our sensory input capabilities. How much of physics is being discovered today through indirect measurements? What would we understand (or how much more) if we could observe these elements directly?
June 22nd, 2007 at 2:13 pm
“I often use the genome analogy …There’s a lot of superfluous junk in our genome…”
Again, I suspect we simply don’t comprehend the functionality of “the junk” and that it plays a significant role in the differentiation between species AND individuals. Some of it is probably junk or inactive remnants, but there is more than likely more to it than commonly held belief.
Just about when everyone agrees on something is when we should really begin to question the validity of it…whatever IT is.
June 22nd, 2007 at 3:32 pm
“Again, I suspect we simply don’t comprehend the functionality of “the junk” and that it plays a significant role in the differentiation between species AND individuals.”
I believe that a large amount of genetic junk is never transcripted into protein, in which case it really does have no function. It’s simply good at replicating itself.
June 22nd, 2007 at 4:13 pm
Tom wrote:
This sounds a great deal like Introns. Excerpted from the Wikipedia page:
Introns don’t transcribe into proteins, but that’s not all that a genetic sequence has as a job. Another supposed “junk DNA” is telomeres, which are essentially “buffer” zones in the chromosome; malfunctions in their process, or removal of them, results in cancer.
Just injecting a little info here.
June 22nd, 2007 at 4:18 pm
http://www.newscientist.com/article/mg19426086.000-junk-dna-makes-compulsive-reading.html
This talks about sections of DNA that get transcripted into RNA into proteins…and how some sections very well may impact the expression of proteins and how much protein or the timing of when a protein expression occurs.
I know we’re straying from the original complexity topic. It’s just that I keep thinking there is simplicity and elegance in much of nature and we often only recognize it afterwards. Until then nature tends to guard her secrets in plain sight and we just can’t or don’t see them.
I can’t locate the article I read that talks about how the junk sections might be what triggers the differentiation of cells in the development of embryonic stem cells.
June 25th, 2007 at 7:19 am
One thing I have to point out is that there is no proof of consciousness being all that complex anyway. Just because we cannot yet replicate ‘human intelligence’ doesn’t suggest that it is complex, merely that we are simpler than we (or you) would like to imagine.
Theoretical Physics really did hit a wall a long time ago, and it is mostly due to our lack of understanding of the reality of the universe, and it’s gulfs of time and space, inaccessible to our species for ever unto eternity.
We really are just an isolated singularity of evolution, and the only possible interaction we may experience is if we are discovered by another, far, far, far more advanced species which was not hostile to us.
A simple universe resonates well with my need to feel less complex, as I don’t like the Idea of transhumanism that much, nor the idea of ringworlds and those other deathstar style ones (what are they called again). We should really reconnect with the Earth, for if it should fail, so shall we, and there aint a megabot in the universe that could save us then, except maybe Deep Thought. (lol)
June 25th, 2007 at 11:38 am
Much so-called junk is probably structurally important for the DNA or important in directing the expression of DNA, especially via interaction with transcription and packaging machinery. Other junk may be related to genetic rearrangement via crossing over. Of course, RRNA and TRAN are also active without being translated. I bet much really is junk,but much that isn’t transcribed is also functional.
June 26th, 2007 at 12:43 pm
Re: Comment #10, this thread.
I refuse to walk the path of suicide. The earth will die, it is inevitable. I refuse to mandate that humanity die with it.
June 27th, 2007 at 10:04 am
Given that I’m resistant to the concept that my own lifespan be limited by death and would fight to prevent it I am with IanC on Comment #10.
IMHO it is the very essence of life to continue living…and to propogate.
That is about as simplistic a drive as I can make. Again as I fade away from the theme of the post.
June 27th, 2007 at 11:52 am
Mike, if all universes are mathematical, then it doesn’t increase the likelihood that any given universe is a simulation. I personally don’t consider the simulation argument compelling because I doubt posthumans would make historical simulations, mainly due to the large amount of disutility going on in them. Even utility-indifferent posthumans could probably derive the questions they want to answer through inference and sequence prediction alone, rather than necessitating a line-by-line simulation. Of course, you can never know for sure whether or not you’re in a simulation.
George, yeah I mentioned that the universe needs to be complex enough to contain observers in the post… there may not be superfluous junk in the universe because universes might not be produced by natural selection. If they are, then black holes may be the reproductive mechanism, so universes with more baby-universe-creating black holes would be selected for.
Patrick, “the need to feel less complex” is not real evidence one way or the other, so you might as well discard it in your thinking… theoretical physics did not “hit a wall”, and there’s no special reason for implicating our lack of intelligence instead of, say, 1) inadequate particle accelerators, 2) not enough emphasis on experiment, 3) inherent hardness of the problem, or whatever.
In these threads, keep in mind there’s an automatic tendency/pressure to talk about simpler, better understood stuff like junk DNA. (Not saying junk DNA is fully understood, there’s just more knowledge about it than anthropics.) But we should keep the talk focused on the esoteric weird stuff if possible… push that intellectual edge!
June 27th, 2007 at 2:06 pm
Multiple implementations (simulations) can run the same universe, and that same universe can be taken as existing as mathematical entity without any simulation. So question whether some universe is a simulation or not is meaningless in this setting.
June 27th, 2007 at 2:47 pm
Michael; speaking of — this post of mine is right up your alley (as a fellow atheist, that is.)
June 29th, 2007 at 2:09 pm
Here’s a site investigating the nature of reality
http://treeincarnation.com/
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