If a computation can be a universe, and a universe a computation, then you’re 90% of the way to Tegmark IV anyway.
The Tegmark IV hypothesis is a conjunction of “the universe is a computation” and “every computation exists as a universe with some weighting function”. The latter part is much more surprising, so accepting the first part does not get you 90% of the way to proving the conjunction.
The Tegmark IV hypothesis is a conjunction of “the universe is a computation” and “every computation exists as a universe with some weighting function”.
I interpret it more as an (attempted) dissolution of “existing as a universe” to “being a computation”. That is, it should be possible to fully describe the claims made by Tegmark IV without using the words “exist”, “real”, etc., and it should furthermore be possible to take the question “Why does this particular computation I’m in exist as a universe?” and unpack it into cleanly-separated confusion and tautology.
So I wouldn’t take it as saying much more than “there’s nothing you can say about ‘existence’ that isn’t ultimately about some fact about some computation” (or, I’d prefer to say, some fixed structure, about which there could be any number of fixed computations). More concretely, if this universe is as non-magical as it appears to be, then the fact that I think I exist or that the universe exists is causally completely determined by concrete facts about the internal content of this universe; even if this universe didn’t “exist”, then as long as someone in another universe had a fixed description of this universe (e.g. a program sufficient to compute it with arbitrary precision), they could write a program that calculated the answer to the question “Does ata think she exists?” pointed at their description of this universe (and whatever information would be needed to locate this copy of me, etc.), and the answer would be “Yes”, for exactly the same reasons that the answer is in fact “Yes” in this universe.
So it seems that whether this universe exists has nothing to do with whether or not we think it does, in which case it’s probably purely epiphenomenal. (This reminds me a lot of the GAZP and zombie arguments in general.)
I’m actually having a hard time imagining how that could not be true, so I’m in trouble if it isn’t. I’m also in trouble if it is, being that the ‘weighting function’ aspect is indeed still baffling me.
So it seems that whether this universe exists has nothing to do with whether or not we think it does, in which case it’s probably purely epiphenomenal.
We probably care about things that exist and less about things that don’t, which makes the abstract fact about existence of any given universe relevant for making decisions that determine otherwise morally relevant properties of these universes. For example, if I find out that I don’t exist, I might then need to focus on optimizing properties of other universes that exist, through determining the properties of my universe that would be accessed by those other universes and would positively affect their moral value in predictable ways.
If being in a universe that exists feels so similar to being in a universe that doesn’t exist that we could confuse the two, then where does the moral distinction come from?
(It’s only to be expected that at least some moral facts are hard to discern, so you won’t feel the truth about them intuitively, you’d need to stage and perform the necessary computations.)
You wake up in a magical universe with your left arm replaced by a blue tentacle. A quick assessment would tell that the measure of that place is probably pretty low, and you shouldn’t have even bothered to have a psychology that would allow you remain sane upon having to perform an update on an event of such improbability. But let’s say you’re only human, and so you haven’t quite gotten around to optimize your psychology in a way that would have this effect. What should you do?
One argument is that your measure is motivated exactly by assessing the potential moral influence of your decisions in advance of being restricted to one option by observations. In this sense, low measure shouldn’t matter, since if all you have access to is just a little fraction of value, that’s not an argument for making a sloppy job of optimizing it. If you can affect the universes that simulate your universe, you derive measure from the potential to influence those universes, and so there is no sense in which you can affect universes of greater measure than your own.
On the other hand, if there should be a sense in which you can influence more than your measure suggests, that this measure only somehow refers to the value of the effect in the same universe as you are, whatever that means, then you should seek to make that much greater effect in the higher-measure universes, treating your own universe in purely instrumental sense.
The Tegmark IV hypothesis is a conjunction of “the universe is a computation” and “every computation exists as a universe with some weighting function”. The latter part is much more surprising, so accepting the first part does not get you 90% of the way to proving the conjunction.
I interpret it more as an (attempted) dissolution of “existing as a universe” to “being a computation”. That is, it should be possible to fully describe the claims made by Tegmark IV without using the words “exist”, “real”, etc., and it should furthermore be possible to take the question “Why does this particular computation I’m in exist as a universe?” and unpack it into cleanly-separated confusion and tautology.
So I wouldn’t take it as saying much more than “there’s nothing you can say about ‘existence’ that isn’t ultimately about some fact about some computation” (or, I’d prefer to say, some fixed structure, about which there could be any number of fixed computations). More concretely, if this universe is as non-magical as it appears to be, then the fact that I think I exist or that the universe exists is causally completely determined by concrete facts about the internal content of this universe; even if this universe didn’t “exist”, then as long as someone in another universe had a fixed description of this universe (e.g. a program sufficient to compute it with arbitrary precision), they could write a program that calculated the answer to the question “Does ata think she exists?” pointed at their description of this universe (and whatever information would be needed to locate this copy of me, etc.), and the answer would be “Yes”, for exactly the same reasons that the answer is in fact “Yes” in this universe.
So it seems that whether this universe exists has nothing to do with whether or not we think it does, in which case it’s probably purely epiphenomenal. (This reminds me a lot of the GAZP and zombie arguments in general.)
I’m actually having a hard time imagining how that could not be true, so I’m in trouble if it isn’t. I’m also in trouble if it is, being that the ‘weighting function’ aspect is indeed still baffling me.
We probably care about things that exist and less about things that don’t, which makes the abstract fact about existence of any given universe relevant for making decisions that determine otherwise morally relevant properties of these universes. For example, if I find out that I don’t exist, I might then need to focus on optimizing properties of other universes that exist, through determining the properties of my universe that would be accessed by those other universes and would positively affect their moral value in predictable ways.
If being in a universe that exists feels so similar to being in a universe that doesn’t exist that we could confuse the two, then where does the moral distinction come from?
(It’s only to be expected that at least some moral facts are hard to discern, so you won’t feel the truth about them intuitively, you’d need to stage and perform the necessary computations.)
You wake up in a magical universe with your left arm replaced by a blue tentacle. A quick assessment would tell that the measure of that place is probably pretty low, and you shouldn’t have even bothered to have a psychology that would allow you remain sane upon having to perform an update on an event of such improbability. But let’s say you’re only human, and so you haven’t quite gotten around to optimize your psychology in a way that would have this effect. What should you do?
One argument is that your measure is motivated exactly by assessing the potential moral influence of your decisions in advance of being restricted to one option by observations. In this sense, low measure shouldn’t matter, since if all you have access to is just a little fraction of value, that’s not an argument for making a sloppy job of optimizing it. If you can affect the universes that simulate your universe, you derive measure from the potential to influence those universes, and so there is no sense in which you can affect universes of greater measure than your own.
On the other hand, if there should be a sense in which you can influence more than your measure suggests, that this measure only somehow refers to the value of the effect in the same universe as you are, whatever that means, then you should seek to make that much greater effect in the higher-measure universes, treating your own universe in purely instrumental sense.