On Thu, Mar 01, 2007 at 09:13:40PM +1100, Stathis Papaioannou wrote: > As you probably know, Hutter proved that the optimal behavior of a > goal seeking agent in an unknown environment (modeled as a pair of > interacting Turing machines, with the enviroment sending an
That's not much of a model, though. > additional reward signal to the agent that the agent seeks to > maximize) is for the agent to guess at each step that the > environment is modeled by the shortest program consistent with the That's definitely not very much of a model. > observed interaction so far. The proof requires the assumption > that the environment be computable. Essentially, the proof says We don't know whether the universe is really computable. It looks that way, but there's no conclusive proof in yet. > that Occam's Razor is the best general strategy for problem > solving. The fact that this works in practice strongly suggests > that the universe is indeed a simulation. How does that follow? What exactly do you consider a simulation? > With this in mind, I offer 5 possible scenarios ranked from least > to most likely based on the Kolmogorov complexity of the > simulator. I think this will allay any fears that our familiar > universe might suddenly be switched off or behave in some radically > different way. That's a reasonably irrational fear to have. Besides, the space of most universes doesn't tolerate existance of matter and thus observers. It won't hurt at all. > 1. Neurological level. Your brain is connected to a computer at > all the input and output points, e.g. the spinal cord, optic and > auditory nerves, etc. The simulation presents the illusion of a > human body and a universe containing billions of other people like > yourself (but not exactly alike). The algorithmic complexity of > this simulation would be of the same order as the complexity of > your brain, about 10^13 bits (by counting synapses). You could have counted the peas in your pantry, and arrived at an equally useful number. The entire dendritic tree computes, so feel free to add a few more orders of magnitude. Quite a bit more, in fact. And you should also look at the amount of ops, you might get a big surprise there, too. > 2. Cognitive level. Rather than simulate the entire brain, the > simulation includes all of the low level sensorimotor processing as > part of the environment. For example, when you walk you don't > think about the contraction of individual leg muscles. When you > read this, you think about the words and not the arrangement of > pixels in your visual field. That type of processing is part of > the environment. You are presented with a universe at the symbolic > level of words and high-level descriptions. This is about 10^9 > bits, based on the amount of verbal information you process in a > lifetime, and estimates of long term memory capacity by Standing > and Landauer. You're not a speech process. You're not the sum of the bits landing in your long-term memory. > 3. Biological level. Unlike 1 and 2, you are not the sole > intelligent being in the universe, but there is no life beyond > Earth. The environment is a model of the Earth with just enough > detail to simulate reality. Humans are modeled at the biological > level. The complexity of a human model is that of our DNA. I I'm really curious what makes you think you're just your DNA. I also warmly recommend reading http://www.amazon.com/Birth-Mind-Creates-Complexities-Thought/dp/0465044069/sr=8-1/qid=1171483943/ref=pd_bbs_sr_1/105-4534151-3528451?ie=UTF8&s=books > estimate 10^7 bits. I know the genome is 6 x 10^9 bits > uncompressed, but only about 2% of our DNA is biologically > active. Also, many genes are copied many times, and there are You're managed to make laugh out aloud for several times now. Hint: there's something severely wrong with the method by which you produce your estimates. (I know, because I once also cheerfully pulled such numbers from nether regions, but got better since). > equivalent codons for the same amino acids, genes can be moved and > reordered, etc. > 5. Mathematical level. The universe we observe is one of an > enumeration of all Turing machines. Some universes will support > life and some won't. We must, of course, be in one that will. The > simulation is simply expressed as N, the set of natural numbers. > Each level increases the computational requirements, while > decreasing the complexity of the program and making the universe > more predictable. I wish really people would quite consistently, because a casual reader will not be able to attribute who said what. http://www.netmeister.org/news/learn2quote.html is a good place, and posting plaintext-only (not multipart, and certainly not HTML-only is a very good idea, too). > You don't need much of a computer for level 5. A single physical > state, perhaps the null state, can be considered an infinitely > parallel computer mapping onto the natural numbers - indeed, mapping > onto any computation you like under the right interpretation. This is > sort of trivially obvious, like the assertion that a short string of > symbols contains every possible book in every possible language if you > interpret and re-interpret the symbols in the right way. In the case > of the string, this isn't very interesting because you need to have > the book before you can find the book. But in the case of > computations, those which have observers will, as you suggest, > self-select. Why would they self-select? I never understood the part where the information about which frames of the trajectory to pick came from but from some place external. The visible universe contains a lot of bits. There is zero evidence of infinities in this universe. Postulating the existance of an external infinite object embedding this (and all possible) universe(s) without further evidence strikes me as those of "not even wrong" type of theories. -- Eugen* Leitl <a href="http://leitl.org";>leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE ----- This list is sponsored by AGIRI: http://www.agiri.org/email To unsubscribe or change your options, please go to: http://v2.listbox.com/member/?list_id=11983
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