That’s all very interesting, but I don’t think it makes the right point about how likely a universe in which beings could develop and comment, would be orderly in the future. I don’t really care how many copies there are of “me” anyway, and that’s not even definable since the variations are graduated. It just isn’t what matters. What matters is the overall picture of “someone/s” and “how many universes” of different kinds can they end up in, even temporarily. Also, you still seem stuck on “programs” and don’t realize that the descriptions themselves are the larger field of platonic realms. The programs come up with descriptions, but why not just think of the descriptions directly … Programs are a biased and limiting concept, since you will imagine rules specifying outcomes, but really any description (configuration of distributions, characteristics, events, etc.) is a part of the platonic omniverse. That omniverse is too large for us to have any hope sans “controlling authority” of randomly ending up in a universe with a predictable continuation, no matter what “happened” in that world up to the time of asking the questions (and regardless of how you conceptualize time.)

BTW, considering the delicate timing of synapse firings and how they come together to influence another neuron to fire, not in a specific classically predictable way (or explain that it is), the brain is not like a computer. Each neuron is on an edge of maybe firing and maybe not, depending on a rough and sloppy sensitivity to the frequency of other signals arriving at about the same time. The butterfly effect and indeterminacy of electrons etc. ruins any attempt to make either individual neurons or the brain into computing machines, and aside from whether specific speculations like QM in microtubules pan out.

I think that Schhmidhuber explains it in this article.

You could also reason heuristicaly like this. Clearly not all worlds can be equally likely, because there are an infinite number of possible worlds. You cannot define a correctly normalized probability distribution that is constant over an infinite set.

Suppose that the probability of a world, which in our setting is just a program or algorithm, depends only on program length. Then the probability that you will find yourself in a particular world will be the proportional to the probability of that world multiplied by the number of copies of you that exist in tat world.

For any given program P, you can consider the program P(n) which just runs P n times. Then the probability that you’ll find yourself in
P(n) is n times the intrinsic probability of
p(n). But this means that the probability of P(n) has to fall of faster than 1/n. otherwise you can’t properly normalize the probability.

Now, the program p(n) will have to have
Log(n)/Log(2) extra instructions compared to P just to program the number n into it. The n-dependence of the program size will thus be

Log(n)/Log(2)

And you see that 2^(-program length) is proportional to 1/n.

I’m adding you to my blog roll.

I can’t imagine that the orderly universes would be more numerous than the disorderly ones (consider which is more numerous: orderly possible arrangements of pixels, or disorderly ones….) but in any case, please explain “…as long as the measure falls of faster than 2^(-program length) you’ll exponentially supress “messy worlds”…” Well, maybe “as long as”, but why should it be so, and could you take a minute to justify the conditional, since I am not really hip on that sort of framing of the issue.

(A friend of mine read TWF just before bed and woke up from a nightmare screaming, “I don’t even know what the f—k a cobordism is!” Seriously.)

That just cracked me up… I feel much better. Give them my apologies, though, and tell them to read Wikipedia before bed instead.

Sean, knowing you, there is a high probability that you have already read it, but if you have not you are bound to enjoy it: Miguel de Unamuno wrote the book, literally, on this subject above (El Sentido Tragico de la Vida). Hopefully the English translation does justice to the original.

(Trivia: If you have seen the Oscar winning “Belle Epoque”, the priest hangs himself and is found holding a book in his hand. This is it. I guess that tells you something)

Big hug from Chicago,

I don’t buy your argument about the brain not being equivalent in principle to a program that can be run on a computer. Brain processes can be described well by classical laws of physics…

About time, I don’t think that time really exists in the sense of a pointer making the “now” real and the past and the future not real. I think that the past, this moment and the future are all equally real. The description of what is happening today can be extracted, in principle from the description of the events in the early universe.

If our universe had magically disappeared one second after the Big Bang we would still have experienced being alive 13.7 billion years after the Big Bang. This is because our mental experience can, in principle, be defined in terms of quantum fields and reformulated in terms of fields at any time in the history of the universe, using a unitary transformation.

Strong AI implies that it doesn’t matter how you generate a particular person. You could just as well replace a brain by an ants nest, if the ants perform the same tasks as the neurons, neurotransmitters etc. Therefore “today” also exists in a hidden way in “yesterday” and thus also in the early universe. To me all this suggests that the notion of a physical universe is bogus.

You’d have to wonder about anyone who wouldn’t take that kind of blue pill.

That is an interesting site, but still flawed by focusing on “programs” instead of the broader model-world notion of “descriptions.” Note that I don’t think this stuff works, I am trying to do a reductio on it. We can’t really frame the issue of possible universes with precision, so the argument is a matter of degree (all that is needed to show implausibility when the case is strong enough.) I am saying that the measure, the range of the possible, prefers worlds with greater inconsistency and messiness of how things work. Therefore our expectation of the sun shining later in the Sahara would be unfounded in a model world we’d be likely to be members of. We do have such expectations, so we didn’t find ourselves in a random possible description (talk of “programs” being a slick way to imply necessary orderliness that wouldn’t reliably be there.) I say we found ourselves in an “intended” world, make of it what you will.

BTW: Do you believe time is real? It, like “existence,” can’t be defined in purely logical terms. All we get when trying is a sort of “distribution” of points or descriptions, with structural differences in the world lines etc. We can’t state the qualitative essence of “duration” itself.

Your point about the brain is a common misconception. There being laws concerning the constituents does not necessitate a formal computational scheme. Note that much of what happens is not really a “law” but probability, which is only “lawful” in an informal, unreliable, bastardized sense (which few admit.) It’s not just probability concepts applied to an otherwise crisp framework anyway, since “what’s there” can’t really be properly described (all those electrons etc.) as anyone reading and appreciating quantum mechanics (collapse of the wave function, what is really moving out there) readily admits. Many good thinkers have posited that the mind is more needed to keep the universe coherent than the other way around.

I define the qualia as the things we can experience, but we can descibe them using a formal description of te brain.

You wrote earlier:

However, I don’t think modal realism works. The totality of descriptions is too large, and includes too many chaotic possible behavior profiles. If we were a modal possible description that had our history up to this point, we couldn’t expect rational continuation of the orderly behavior that we’ve had so far. Why not? Because “laws” wouldn’t be either some controlling vitus or expression of the identity of a substance. They would just be after the fact generalizations (as Hume pointed out, per pure rational assessment) of whatever things did. I can describe a world where the “law of attraction” goes to 1/r^1.13 or whatever, at any time, or distance, or a continuum of complex disconnected behaviors, because those are all descriptions. Hence, there’s an infinitesimal chance of ending up in a world – even given orderly behavior up to a given time – that continues to express itself lawfully. (And relativistic simultaneity is itself a rule that could be broken by such descriptions.)

You need to define a measure on the set of all possible formal descriptons that prefers worlds with lower complexity. Otherwise the principle of Occam’s Razor would not work.

See here for a proposal that does work

John, I completely agree with you. That is the plan. My hope is that I become comfortable with the idea of death before I die. Unfortunately this is rather difficult as it goes completely against what we as humans have evolved to feel. But as Garrett said, the “serotonin levels seem to rise and stabilize as one gets older” so it probably wont be a problem in the not so near future. Maybe my hope was that if god did actually exist I would work this out in time to save my immortal soul. I don’t know - so much thinking and still no idea what is going on!

Yeah, Shintoism is truly a “religion of peace” - about as much as Islam is. Just ask the Ainu/Chinese/Koreans.

If materialists were to feel regretful about their beliefs, it would be
unbecoming of their logical character to find comfort through that move.

If nothing exist, then I am the only person who will really see what I write here and one day I will not know I wote this.

Here’s an idea: why don’t you co-write that book with Sean Carroll the evo-devo guy?