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Ishaan comments on Does the simulation argument even need simulations? - Less Wrong
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I actually arrived at this believe myself when I was younger, and changed my mind when a roommate beat it out of me. I
I'm currently at the conclusion it's not the same, because an "artificial universe" within a simulation can still interact with the universe. The simulation can influence stuff outside the simulation, and stuff outside the simulation can influence the simulation.
Oddly, the thing that convinced me was thinking about morality. Thinking on it now, I guess framing it in terms of something to protect really is helpful. Ontological platonism can lead to some fucked up conclusions, morally. I'll share a fleshed-out version of the thought-chain that changed my mind.
Review the claim, briefly:
1) So, if I set the initial conditions for a universe containing Suffering Humans, I'm not responsible - the initial conditions of the Hell-universe existed Platonically regardless of the fact that i defined it in the mathematical space.
2) Alright, so now what if I run the Hell Universe? Well, platonically speaking I already specified the entire universe when I laid out the initial conditions, so I don't see why running it is a big deal.
So we are currently running a Simulation of Hell, with a clean conscience. If you haven't already bailed from this ontology, lets continue...
3) Mathematically, the Hells which happen to have Anne inserted at time T were already in the platonic space of possible universes, so why not set the conditions and run that universe? Anne is a real person, by the way - we're just inserting a copy of her into the hell-verse
4) Anne just uploaded her consciousness onto a hard drive. Hold on...Anne can now be thought of as a self contained system, with input and output. Anne's consciousness is defined in the platonic space, as are all possible inputs and outputs that she might experience. If every input we might subject Anne to is already defined in platonic space, it makes no difference which one we choose to actually represent on the computer...
...Anyway, you see where this leads. Now forget the morality part - that was just to illustrate the weaknesses of Platonic ontology. Considering all mathematical structures equally "real" makes the concept of "reality" lose all meaning. There is something very important which distinguishes reality from non-real mathematical universes - the fact that you can observe it. The fact that it can interact with you.
This might seem less obvious when you're unsure whether or not your universe is a simulation, but it's obvious to the parent universe. If we ever start simulating things, we're not going to think of it as simply a representation specifying a point in platonic space - we're going to think of the simulated world as a part of our reality.
That's not a bullet...I'd say you were biting a bullet if you didn't believe that. Reality has to be a mathematical construct - if it isn't, we've just thrown logic out the window. But that doesn't mean anyone was sitting around writing the equation.
Reality is also special. It's different from all those other mathematical constructs, because I will only ever observe reality.
I don't think we should be calculating likelihoods this way.
I go to good-old Occam's razor (or more modernly, Mimimum Message Length). Does the simulation argument make for a simpler model? As in, can you actually suggest me a universe in which we are a simulation which is simpler than the universe outlined by vanilla physics? (The answer isn't necessarily "no", but I'd say that the simpler the laws we observe, the more likely the answer is to be "no". If we live in a more complicated universe - especially if the laws of the universe seemed to care about agents (the fact that we are even here does up the probability of that) - the answer might be 'yes". That said. I'd still bet on "no".)
I think this leads to unpleasant conclusions. If causality is all we care about, does that mean we shouldn't care about people who are too far away to interact with (e.g. people on an interstellar colony too far away to reach in our lifetime)? Heck, if someone dived into a rotating black hole with the intent to set up a civilization in the zone of "normal space" closer to the singularity, I think I'd care about whether they succeeded, even though it couldn't possibly affect me. Back on Earth, should we care more about people close to us and less about people further away, since we have more causal contact with the former? Should we care more about the rich and powerful than about the poor and weak, since their decisions are more likely to affect us?
If you don't consider the possibility of being simulated it seems like you would make wrong decisions. Suppose that you agree with Bob to create 1000 simulations of the universe tonight, and then tomorrow you'll place a black sphere in the simulated universes. Tomorrow morning Bob offers to bet you a cookie that you're in one of the simulated universes. If you take the bet on the grounds that the model of the universe in which you're not in the simulation is simpler, then it seems like you lose most of the time (at least under naive anthropics).
Now obviously in real life we don't have this indication as to whether we're a simulation. But if we're trying to make a moral decision for which it matters whether we're in a simulation, it's important to get the right answer.
Didn't say that. We might be in a simulation. The question is, is that the more parsimonious hypothesis?
Observation is the king of epistemology, and Parsimony is queen. If parsimony says we're simulated, then we're probably simulated. In the counter-factual world where I have a memory of agreeing with Bob to create 1000 simulations, then parsimony says I'm likely in a simulation. We might be in a universe where the most parsimonious hypothesis given current evidence is simulation, or we might not. Would that I had a parsimony calculator, but for now I'm just guessing not.
There are observations that might lead a simulation hypothesis to be the most parsimonious hypothesis. I claim it as a question which is ultimately in the realm of science, although we still need philosophy to figure out a good way to judge parsimony.
These two statements sum my current stance.
Epistemic Rationality: Take every mathematical structure that isn't ruled out by the evidence. Rank them by parsimony.
CDT (which I'll take as "instrumental rationality" for now):: If your actions have results, you can use actions to choose your favorite result.
so, applying that to the points you raised...
I have sufficient evidence to believe that both the poor and the rich exist. I care about them both. In the counter-factual world where I was more certain concerning the existence of the rich and less certain containing the existence of the poor, then it would make sense to direct my efforts to the rich.
If I want to give people utils, and If I can give 10 utils to person R if I have 70% certainty that they exist to benefit from it, or 20 utils to person P if I have 10% certainty that they exist to benefit from it, I obviously choose person R.
Back to reality: I've got incredible levels of certainty that both the rich and the poor exist.
Once again, it's a question of certainty that they exist. If I told you that donating $100 to the impoverished Lannisters would be efficient altruism, wouldn't you want to check whether such people truly exist and whether the claims I made about them are true?
You'd put every effort into assuring that they succeeded before they dived into the black hole and became causally disconnected from you. Afterwords, you're memory of them would remain as evidence that they exist...you'd hope they were doing alright, but you have no way of knowing and your actions will not effect them now.
taboo care...
Given your current observations, what likelihood can you assign to their existence? (emotional reactions like "care" will probably follow from this).
Can you help them or hurt them via your actions?
So of course you'd care ... in proportion to your certainty that they exist.
It seems to me the most parsimonious hypothesis is that the human race will create many simulations in the future - that seems like the natural course of progress, and I think we need to introduce an additional assumption to claim that we won't. If we accept this then the same logic as if we'd made that agreement with Bob seems to hold.
Hang on. You've gone from talking about "what I can interact with" to "what I know exists". If logic leads us to believe that non-real mathematical universes exist (i.e. under available evidence the most parsimonious assumption is that they do, even though we can't causally interact with them), is that or is that not sufficient reason to weigh them in our moral decisionmaking?
My mistake for using the word "interaction" then - it seems to have different connotations to you than it does to me.
Receiving evidence - AKA making an observation - is an interaction. You can't know something exists unless you can causally interact with it.
How can something non-real exist?
I dispute the idea that what does or does not exist is a question of logic.
I say that logic can tell you how parsimonious a model is, whether it contains contradiction, and stuff like that.
But only observation can tell you what exists / is real.
I'd argue that any simulations that humanity makes must be contained within the entire universe. So adding lower simulations doesn't make the final description of the universe any more complex than it already was. Positing higher simulations, on the other hand, does increase the total number of axioms.
The story you reference contains the case where we make a simulation which is identical to the actual universe. I think that unless our universe has some really weird laws, we won't actually be able to do this.
Not all universes in which humanity creates simulations are universes in which it is parsimonious for us to believe that we are someone's simulation.
You're right, I was being sloppy. My point was: suppose the most parsimonious model that explains our observations also implies the existence of some people who we can't causally interact with. Do we consider those people in our moral calculations?
I can see the logic, but doesn't the same argument apply equally well in the "agreement with Bob" case?
True, but only necessary so that the participants can remember being the people they were outside the simulation; I don't think it's fundamental to any of the arguments.
This is impossible. No causal interaction means no observations. A parsimonious model cannot posit any statements that have no implications for your observations.
But I understand the spirit of your question: if they had causal implications for us, but we had no causal implications for them (implying that we can observe them and they can effect us, but they can't observe us and we can't effect them) then I would certainly care about what happened to them.
But I still can't factor them into any moral calculations because my actions cannot effect them, so they cannot factor into any moral calculations. The laws of the universe have rendered me powerless.
and
I'm not sure I follow these two statements- can you elaborate what you mean?
Wait, what?
So, I go about my life observing things, and one of the things I observe is that objects don't tend to spontaneously disappear... they persist, absent some force that acts on them to disrupt their persistence. I also observe things consistent with there being a lightspeed limit to causal interactions, and with the universe expanding at such a rate that the distance between two points a certain distance apart is increasing faster than lightspeed.
Then George gets into a spaceship and accelerates to near-lightspeed, such that in short order George has crossed that distance threshold.
Which theory is more parsimonious: that George has ceased to exist? that George persists, but I can't causally interact with him? that he persists and I can (somehow) interact with him? other?
Suppose my current actions can affect the expected state of George after he crosses that threshold (e.g., I can put a time bomb on his ship). Does the state of George-beyond-the-threshold factor into my moral calculations about the future?
That George persists, but I can't causally interact with him.
Yes.
My rule: "A parsimonious model cannot posit any statements that have no implications for your observations" has not been contradicted by my answers. The model must explain your observation that a memory of George getting into that spaceship resides in your mind.
As to whether or not George disappeared as soon as he crossed the distance threshold...it's possible, but the set of axioms necessary to describe the universe where George persists is more parsimonious than the set of axioms necessary to describe the universe where George vanishes. Therefore, you should assign a higher likelihood to the probability that George persists.
This is the solution to the so called "Problem" of Induction. "Things don't generally disappear, so I'll assume they'll continue not disappearing" is just a special case of parsimony. Universes in which the future is similar to the past are more parsimonious.
I basically agree with all of this.
So, when lmm invites us to suppose that the most parsimonious model that explains our observations also implies the existence of some people who we can't causally interact with, is George an example of what lmm is inviting us to suppose? If not, why not?
TheOtherDave's already covered this part
Second one first:
The only reason we need to assume the simulation is identical to the outer universe is so that our protagonists' memory is consistent with being in either. The only reason this is a difficulty at all is because the protagonists need to remember arranging a simulation in the outer universe for the sake of the story, as that's the only reason they suspect the existence of simulated universes like the one they are currently in.
If the protagonists have some other (magical, for the moment) reason to believe that a large number of universes exist and most of those are simulated in one of the others, it doesn't matter if the laws of physics differ between universes - I don't think that's essential to any of the other arguments (unless you want to make an anthropic argument that a particular universe is more or less likely to be simulated than average because of its physical laws).
Now for my first statement.
Your argument as I understood it is: Even if the most parsimonious explanation of our observations necessitates the existence of an "outer" universe and a large number of simulated universes inside it, it is still more parsimonious to assume that we are in the "outer" universe.
My response is: doesn't this same argument mean that we should accept Bob's bet in my example (and therefore lose in the vast majority of cases)?
See the response to TheOtherDave
Then there has been a miscommunication at some point. If you rephrase that as:
"Even if the most parsimonious explanation of our observations necessitates the existence of an "outer" universe and a large number of simulated universes inside it, it is still sometimes more parsimonious to assume that we are in the "outer" universe."
Then you'd be right. The fact that we have the capacity to simulate a bunch of universes ourselves doesn't in-and-of-itself count as evidence that we are being simulated. My argument is more or less identical to V_V's in the other thread.
I would agree with that statement. If our universe turns out to have a ridiculously complex set of laws, it might actually be more parsimonious to posit an Outer Universe with much simpler laws which gave rise to beings which are simulating us. (In the same way that describing the initial conditions of the universe is probably a shorter message than describing a human brain)
I agree, and I'd like to offer additional argument. Mathematical objects exist. Almost no one would deny that, for example, there is a number between 7,534,345,617 and 7,534,345,619. Or that there is a Lie group with such-and-such properties. What distinguishes Tegmark's claims from these unremarkable statements? Roughly this: Tegmark is saying that these mathematical objects are physically real. But on his own view, this just amounts to saying that mathematical objects are mathematical objects. Yeah yeah Tegmark, mathematical objects are mathematical objects, can't dispute that, but don't much care. Now I'll turn my attention back to tangible matters.
Tegmark steals his own thunder.
I think Tegmark's level 1-4 taxonomy is useful. Strip it of physics and put it to philosophy:
Lv 1) What we can observe directly (qualia)
Lv 2) What we can' t observe, but could be (Russel's teapot)
Lv 3) What we can't observe, but we know might have happened if chance played out differently. (many-worlds)
Lv 4) Mathematical universes.
These are distinct concepts. The question is, where and how do you draw a line and call it reality? (I say that we can't include 4, nor can we only include 1. We either include 1, 2 or 1, 2, 3...preferably the former.)
I took the portion of your comment I quoted to be about level 4 only. Anyway, that is where my comment is aimed, at agreeing that we can't include 4.
Yeah, but unmodified simulations are the same, whereas modified simulations diverge. The fact that something from the outside interacted with the simulation means that it's just one distinguishably-different one out of many. Purely statistically speaking, we'd expect not-screwed-with universes to form the biggest probability block by far.
I'm not quite sure what you mean. Would you mind rephrasing or elaborating?
The evolution of a universe that's not being influenced by its host universe is determined by its initial state. However, any interaction of a host universe with the nested universe adds bits to its description. Therefor, even if we'd numerically expect most host universes to screw with their child universes somehow (which still isn't given!) they'll all screw with them in different ways, whereas the unscrewed-with ones will all look the same. Thus, while most universes may be screwed-with (which isn't even a given!), the set of unscrewed-with universes is still the biggest subset.
No, you can subtract information from things. Edge case: what if the host just replaces every bit in the hard drive with all 0's?
In what? the platonic mathematical space? Or the subset of universes that a given host universe simulates?
I think I do get your meaning, but it doesn't seem very well defined...
Of course you can end up with a state that has a lower minimal description length. However, almost any interaction is gonna end up adding bits.
Yes, and yes this is very ill-defined, and yes it's not clear why the set size should matter, but the simulation argument rests on the very same assumption - some kind of equal anticipation prior over causes for our universe? So if you already accept the premise that universe counting should matter for the simulation argument, you can just reuse that for the "anticipate being in the unscrewed with universe" argument. (Shouldn't you anticipate being in a screwed with universe, even if you don't know in which way it'd be screwed with? Hm. Is this evidence that most hosts end up not screwing with their sims?)
If we're only talking about the platonic mathematical space, then why does it matter what hosts do or do not do to their simulations?
The entire thing (host and simulation) is one interacting mathematical unit. There might also be a mathematical unit that represents the simulation, independently of the host, but we can count that separately.
There are an infinite number of mathematical structures that could explain your observations. An infinite number of those involve simulations, and an infinite number of them don't involve simulations. Of the ones that involve simulations, an infinite number of them are "screwed" with and an infinite number are "unscrewed".
So, if we want to choose a model where everything in the platonic mathematical space is "real" (One one level I want to condemn this as literally the most un-parsimonious model of reality, and on another level I'll just say that you have defined reality in a funny way and it's just a semantic distinction) and then we want to figure out where within this structure we are using the rule that "the likelihood of a statement concerning our location being true corresponds to the number of universes in which it is true and which also fit our other observations", then we have to find a way of comparing infinities.
And that's what you're doing - comparing infinities. So ... what mechanism are you proposing for doing so?
I don't know, but the fact that out of an infinity of possible universes we're practically in the single-digit integers, has to mean something. Ask a genie for a random integer and you'd be surprised if it ever finished spitting out numbers in the lifetime of the universe; for it to stop after a few minutes of talking would be absurd. So either we're vastly wrong about the information theoretic complexity of our universe, or the seeming simplicity of its laws is due to either sampling bias, or MU is wrong and this universe really just happens to just exist for no good answerable reason, there's a ludicrous coincidence at work, or there has to be some reason why we are more likely to find ourselves in a universe at the start of the chain, whose hosts are not visibly screwing with it. The point is to add up to normality, after all.