Apologies for the late post. But I found this argument fascinating and wanted to share my thoughts. Also sorry to see the reception you got on the reddit page. I took a peek at the comments, and they seemed especially dull and mean-spirited. Just a reminder of how much we should cherish philosophical blogs like these I suppose!
Before I get into the meat of your argument, let me make a minor quibble about your points that there is no set of possible observers (the observer reference class is greater than Beth 2):
1. As mentioned already in the comments, not all truths are knowable. So it seems dubious that truths can be put in 1-to-1 correspondence with observers.
2. This assumes that infinite minds count in the set of possible observers. But maybe it doesn't make sense to include such minds in the reference class of possible observers one can be. If so, then (assuming every mind is decomposable into a computational structure with finite parts), we won't be able to construct a diagonal proof showing that there is a mind not in the set of all possible observer-minds, since that mind would have to be describable by a real number (i.e. infinite).
Now into the meat of the argument:
A) It seems to me that there is a lacuna in your argument which has to do with the construction of one's reference class. Endorsing SIA doesn't obviate the need for constructing a reference class, since we still need to define what we think an observer is. Reasonable people can disagree about what constitutes an observer. Particularly, if we accept SIA then we accept that we should reason as if we were sampled from the reference class of all possible observers we could have been. But what constitutes an observer that "we could have been"? Maybe a physicalist might argue that an observer can only be a physical entity which is composed of some finite computational structure (related to point 2 above). It could also be argued that we should only consider ourselves to belong in the reference class of entities which could be physically constructed according to possible natural theories. If so, then hypothetical entities in the Beth 2 realm won't count as observers. And the multiverse counter still goes through.
B) It's not clear to me that atheism is incompatible with Beth 2 worlds. Just because we reject theism doesn't mean we have to accept some common naturalistic alternative (e.g. multiverse theory). Maybe there exists some metaphysical principle (e.g. simpler patterns reproduce into complex repeatable patterns) which governs the construction of worlds, and which entails that there will exist uncountably infinite number of worlds where induction is sound, and little to no worlds where induction is falsified. I don't see why our prior for such a principle must be lower than our prior for theism.
Alternatively, one could simply accept the existence of Beth-2 observers in uncountable number of worlds as a brute fact. One presumably has to endorse a brute fact at some stage (whether God or something else). So the atheist can simply say that they take on a brute fact one step sooner in the explanatory chain. Perhaps this could be retorted with appeals to simplicity (similar to Swinburne's cosmological argument), so that accepting a simpler explanation (i.e. God) as a brute fact is easier. However, I find such arguments really dubious. It's not clear to me that there are metaphysical reasons to favor simplicity. Maybe there are physical reasons to favor simplicity (our universe is constructed such that simpler theories will be more likely to be true), but why should we think that the success of simplicity in the physical world is explained by the existence of a metaphysical rule in favor of simplicity which applies to cases outside our physical universe?
C) I think the reliance on infinite classes is problematic for the argument here. Infinity is especially tricky, as evidenced by cases like the measure problem and Pascal mugging. The problem with infinites in general suggests to me that the real trouble in such cases is that anthropic reasoning in ordinary cases is not equipped to handle infinites, and we need to make modifications like introducing cutoff thresholds (e.g. regularization).
Just as an example. Suppose I told you that I was an interdimensional being who had been in contact with a superintelligence that had discovered a new physical theory which predicted some staggering super-infinite class of observers but also predicted that theism was false. For simplicity, let's just say that this super-infinite class of observers was larger than Beth omega.
Now obviously you aren't going to believe me. But presumably you should assign some vanishingly small, but still finite, prior credence that what I say is true. But now given the insane posterior shift advantage that my theory, if true, would accrue over the theistic theory, it seems that you must endorse my theory.
I think what this reveals is that we simply can't naively reason on infinities in anthropic cases as we would ordinarily do; we need some cutoff value somewhere. But once we introduce a cutoff value, nothing stops the atheist from asserting that the increase in possible observers from aleph-null to Beth-2 goes beyond the cutoff, and thus does not affect the posterior shift in any way. Hence, theism need not be more probable than multiverse theory.
No worries about the late post--thanks for the engagement.
//1. As mentioned already in the comments, not all truths are knowable. So it seems dubious that truths can be put in 1-to-1 correspondence with observers.//
Right so we should modify the principle to be that truths that don't reference themselves being unknown can be put into correspondence with observers.
I don't understand the second point.
In regards to A) The reference class of SIA is the share of observers who one might be currently given their evidence. So I have a reason to think that there are more identical earths because I could right now be on any one of them. There are also Beth 2 possible physically creatable observers--the proof there's no set of observers would show there are more than Beth 2--the Beth 2 proof is different and more modest.
B) It's possible that there are Beth 2 worlds. But it's naturally predicted by theism and absurdly unlikely on atheism. I think theism should have a higher prior than this world because it's very simple, supported by other evidence, and most of all, there is no coherent theory of what the other world is supposed to be like. A physical multiverse theory (in the sense described here https://capturingchristianity.com/why-god-exists-fine-tuning-beauty-and-discoverability/) won't do the trick, especially if there are unsetly many people, and a metaphysical multiverse theory undermines induction by making there be many worlds where induction doesn't work.
You could posit that there are just Beth 2 different worlds for no reason, but that's extremely arbitrary and ad hoc, and furthermore is infinitely complicated because it posits an infinite number of disconnected fundamental things. If there aren't metaphysical reasons to favor simplicity it's hard to see why you should trust induction because there are a lot of ways that reality could stop working one second from now.
C) Yeah infinity is tricky but I feel like I'm using it in a pretty germane way here. Infinity is the least suspicious when there's some pattern that holds in finite cases and you just extrapolate it to the infinite cases. So more people existing is more likely in finite cases (and can be shown to be in infinite cases for similar reasons). It would be really weird if there was a random break in the reference class at infinite people. Furthermore, I think this runs affoul of the arguments given here (in the contraception case, imagine Aleph Null people each creating Beth 2 more people https://benthams.substack.com/p/the-self-indication-assumption-works) and here https://benthams.substack.com/p/alternatives-to-sia-are-doomed (hopefully it should be clear how that would work in those cases, but happy to explain if you're not sure--also happy to discuss this more either on YouTube or discord--shoot me a dm if you want, my discord name is omnizoid).
There's a lot to say here, so I'll try to keep my points as structured as possible.
A) Let me start by tackling the discussion of reference classes. While I agree that SIA simplifies the selection of one's reference class in comparison to SSA, I don't think it solves the problem of reference class choice outright. The trouble is that one still needs a criterion method for what counts as an observer. People will have different intuitions as to who they 'could' have been (given their evidence). This will be based on things like their theory of personal identity and so forth. Should we take into account lesser conscious beings (does it make sense to say that one could have been a slug?). Non-conscious observers (as Schwitzgebel argues here: https://eschwitz.substack.com/p/neurons-arent-special-a-copernican, see the comment chain with our discussion)? Non-physical ectoplasmic soul stuff?
The point is that one needs a criteria method for adjudicating what counts as membership in the reference class of observers, and what does not. Once you admit this, there is reasonable room to disagree as to what the criteria should be. I think the non-theist has room here to argue that we should only take into consideration those beings who could have been created by natural theories of physics. So hypothetical Beth 2 conscious entities in the metaphysical multiverse won't count as observers on this view. Perhaps it could be objected that this membership criterion is ad hoc, but the challenge is in showing any membership criterion which won't seem ad hoc to another person (for instance, I noticed that your membership criteria only takes into account physical entities, and so excludes ectoplasmic conscious souls). Moreover, the atheist could retort that they have good evidence for selecting their membership criteria, namely the physical evidence on hand governing the theory of universe formation.
B) What I had in mind here was a metaphysical multiverse theory where modal realism was false. That's what I was trying to get at with my talk of a metaphysical principle where coherent structural patterns (e.g. brain, universes) are more likely to be created from simpler patterns than non-coherent patterns. Maybe the atheist could endorse such a principle, which would permit the existence of Beth 2 observers in mostly induction friendly universe. I don't want to push this point too hard because this will depend on your priors for theism versus such a metaphysical principle. If you say you have other evidence for theism, then fair enough. The point is that atheists might reasonably disagree though if their priors were different.
About the brute fact stuff. The simplicity issue is complicated but worth discussing because I find that it is so central to theist arguments for God (like Swinburne's cosmological argument). I'll leave this for the end though (see my note below). I assume in the meantime that you agree with me that the objection to be made here is that theism should be preferred as a brute fact explanation because it is simpler (if that's not the case let me know!).
C) I agree that in general extrapolating to simple infinity cases is okay unless one has a defeater. But the point of my inter-dimensional thought experiment was to demonstrate just such a defeater, and why we shouldn't extrapolate in anthropic cases. I didn't really see a response to that point. You mentioned that it would be weird and arbitrary if there was a random break in the reference class at infinity, two points in response:
1- It doesn't have to be a discrete break. Depending on how one conducts regularization one could structure one's probabilities so that each successive observer in one's reference class shifted your posterior by a lesser amount, so it reached a limit at infinity of zero posterior shift.
2- I find the talk of weirdness itself rather strange. I think it's only weird if we adopted something like a frequentist probabilistic approach, and thought that there were objective probabilities. But if probabilities are subjective and Bayesian, as we are assuming, all we are concerned with is what our frame of mind should be. Given this, I don't think it's weird at all to posit that anthropic probabilities break down at infinity. All that indicates is that our minds are not equipped to handle such infinities using the same tools we use to handle finite cases, and that's hardly surprising.
About your posts, I'm not sure what the argument is here but yes obviously the proponent of an infinite cutoff would have to accept that Aleph null people creating Beth 2 more people does not raise one's probabilities of being born. That's just a straightforward consequence of what an infinite cutoff entails, not really sure how that's supposed to be an argument against? Perhaps your second post about the weird consequences of rejecting SIA was intended as the argument? But I think the proponent of the infinite cutoff doesn't have to accept weird effects like the doomsday argument or the Adam and Eve acausal powers, supposing that the finite pool of possible observers were still large enough to offset such effects (e.g. one's birth rank being unusual).
Note on simplicity:
I brought up this argument before in an email with Brian Cutter concerning his paper on Nomological harmony (https://philarchive.org/rec/CUTTPO-9), but basically I think theistic reliance on simplicity runs afoul of a nominalist objection. If you're a mathematical nominalist (as I am), then you think definitions of simplicity (e.g. Kolmogorov complexity) will just describe the behavior of particular physical patterns in our universe, and not some deep metaphysical law about the nature of algorithms. But once we accept this, then there's no reason to think that simplicity considerations will apply to metaphysical structures and patterns not governed by our physical laws. So arguments about theistic simplicity are rather dubious on this view, since there's no reason to think that metaphysical structures like God would be governed by such rules.
You do raise the point that we have no grounds for inductive reasoning if metaphysical simplicity is false. But:
1) You could believe in inductive reliability on separate grounds from simplicity, e.g. theism, if one had independent evidence outside of simplicity considerations, or that metaphysical principle I was talking about, or whatever.
2) My above point applies. It's unclear to me how to assign our priors to such scenarios, and whether we should favor a random universe as more likely over a simple patterned one. It's true that most structured algorithms are random as opposed to simple patterns, but for the nominalist, talk of possible algorithms just refers to particular physical behaviors. It happens to be the case that the combinatoric states of physical structures in our universe are such that the random physically possible states (for example, possible states that a random number generator can be in) greatly outnumber the simple patterned states, but perhaps this doesn't apply to other metaphysical structures. Perhaps the metaphysical patterns which govern universe creation don't obey the normal algorithmic rules. In which case, we don't need simplicity considerations to justify our belief that we exist in a well-governed universe (they may just be more likely than random universes).
Hope this all made sense.
P.S. I am busy writing a solution paper to the hard problem of consciousness at the moment, so I might not be able to continue the discussion right away (or make a reply here for that matter), but I'm happy to take you up on your offer for a discord discussion in the near future if you want to continue. Thanks for the offer.
Yes, happy to continue the conversation over discord.
A) You don't need to adjudicate what could *have been* you. You need to adjudicate what currently might be you. I know I'm currently not a bug and that I'm currently not a guy named John in Kansas, so I have no anthropic grounds to think there are more bugs or guys in Kansas. On SIA it doesn't matter how you construe the reference class. For instance, suppose you include bugs and there are 10 times as many bugs as people. Then your existence becomes 10 times as likely but the probability that you'd exist as a person is 1/10 as great, so they exactly cancel each other out. Thus, on SIA the only thing that matters is how many people there are who you currently might be.
B) The problem is that there is no viable metaphysical multiverse model. To have a viable metaphysical multiverse be simple, you have to think that there is some fundamental thing that is instantiated without limit (that's pretty much the definition of a metaphysical multiverse). But there aren't that many fundamental things: they basically are value, math, modality, and beauty maybe. Math unlimited is the Tegmark thing that undermines induction, modality unlimited is modal realism which undermines induction, consciousness unlimited is unclear but maybe either theism or something that undermines induction (if all experiences are instantiated, most of them will have deficient induction), and beauty unlimited would just have a single beautiful thing.
C1) If you shift your posterior by less as there get to be more agents, then the argument I link to surrounding the generalized doomsday argument means that has absurd results in cases with a finite number of observers. In the Adam and Eve case, for instance, where they find out their birth rank, they can predict with very high confidence, in advance, that a poker game will have a royal flush, and get all sorts of other abberant predictions and causation https://benthams.substack.com/p/several-new-arguments-for-the-self?utm_source=publication-search
C2) It's weird for probability to have a discrete break at infinity in this case. To illustrate, imagine that you adopted SIA up to 650 people and then thought it stopped working. That would be weird. Even if you're a Bayesian, sometimes there's a principled reason to assign probabilities to things--e.g. you should think that a coinflip has a probability of .5 of coming up heads, all else equal.
I think the view does have to accept the doomsday argument and other stuff in the infinite case. Imagine that aleph null people are created and then a game of poker will be played. If it gets a royal flush, no extra people are created. If it gets anything else, Beth 2 people are created. Suppose you exist but don't know if you're one of the aleph null people originally or the later Beth 2 people. You reason in the following way: if Beth 2 people are such as to be created (this is the tenseless proposition that whenever the game is played it will have something other than a royal flush), the odds that I'd be one of the first aleph null people are 0--aleph null/Beth 2. Then you find out that you are one of the first aleph null people. Now you can predict in advance that a poker game that hasn't been played yet will have a royal flush based purely on its future consequences, which is clearly illicit and violates certain obvious features of probability https://benthams.substack.com/p/against-biting-the-bullet-on-adam.
One could make a similar argument for the contraception case, for the record.
Re induction and simplicity:
1) You could, but then because theism is a very specific way for reality to be would have an absurdly low prior.
2) It's true that inductive universes can just be likelier than other ones. But ideally we want an explanation of that, and induction working would explain that. If you just say, well maybe there's some explanation of induction other than simplicity that explains it, that's possible, but it just seems really unlikely. It also seems hard, on such a picture, to see why we should assign a low probability to random other stuff existing, like a particular type of particle.
Thanks for the thoughtful engagement! Interesting thoughts!
1. This would also seem to support the evil god hypothesis. If there's only a 1% chance that a good god would create everyone, there seems to be an equal chance that anti-nataliss are right and that there's a 1% chace of an evil god creating everyone as well.
2. This argument defeats psychophysical harmony. If God creates infinite minds, then presumably he will create many minds that are not psychophysically harmonious, and many more which cannot tell the difference. What's to say that you and I are not one of those minds? However, if God really does create every possible mind in a way that's harmonious, then it's unclear why an infinite material universe couldn't do the same. If an infinite universe cannot, why can a (logically constrained) God do so? (Actually this latter point also seems convincing. If there is "no set of all truths" in logic, why can God make one. Are you arguing for some sort of divine transcendence of logic?).
3. This argument seems to also defeat induction in the same way that modal realism does. If an infinite number of actually created minds exists, then surely there are an infinite number of minds where induction spontaniously breaks down, and everything around them turns into cantelopes.
4. One atheist account that solves this argument is to deny that there are other minds exist at all. There is only one possible mind, and it is the mind that is currently experiencing. :P
2. Nope, the evidence is that I, in particular, have a harmonious soul, which is not explained by the fact that I exist.
3. Nope, not any more than the fact that in Hilbert's hotel the same number of people get a royal flush as get a pair means that in the hotel I should think I'll be as likely to get a pair as a royal flush.
4. But the odds that my mind, in particular, would be the only possible mind, when it has no special claim to hat relative to the other conceivable minds, is zero.
2. But if this argument is correct, then you have no way of knowing you in fact have a harminous soul! You could be one of those utterly infinite not-a-set-because-no-set-can-contain-them of minds that experiences things totally disconnected from physical reality. How would one prove that this is not the case?
3. I think this passage from an acquantence of mine answers this argument quite well:
"There are people exactly like me up until this point—and for an infinite number of them, induction fails one second later. Induction, for those that don’t know, is the idea that the future will be like the past, that the fundamental laws of the universe won’t spontaneously break down one second from now, that the sun will rise tomorrow. But for every possible world in which induction works, there are innumerable ones in which it does not."
Is the same thing not true here? If God creates every mind, then there are presumably an infinite number of minds that had the exact same experiences as you, but which then experience something totally random one second from now. In fact, the overwhelming majority of minds that experienced the same things as you will suddenly experience something whacky occur.
So Hilbert's hotel doesn't really work. Firstly, there are far more minds then the mere countable infinity of rooms in the hotel, so the analogy is imperfect. If every mind is created it would be like everyone recieving a poker hand, and then 99.99999%+ of people get a hand that includes cards outside the standard deck. (We can imagine an eleven of clubs, a fifteen of spades, and so on). Seems like you would be a fool to believe you would get an ordinary card, despite induction!
4. Your mind is special -- it's the only mind that must exist. It's entirely possible that there are no other minds. Seems pretty special to me!
2. I do. I observe my mental states are not random static.
3. See the Hilbert's hotel example. There's some sense in which most of the people are not created in a non-inductive world. If each of infinite people has some event happen with 90% probability and another with 10% probability, while the total number of events is the same, my credence in the 90% probability event happening should be 90%.
4. But a priori any particular mind could be the only one that must exist. You assign priors before observing special facts about your mind.
> 2. I do. I observe my mental states are not random static.
You observe that you have mental states. You have no way of knowing that these mental states actually correlate with some external reality.
According to you there exists a mind that has the exact same quality of experiences as you. Now maybe they're not exactly you, but they generally speaking have all the same reasons to believe in psychophysical harmony through observation of their own experiences.
Your problem is that you hold either (1) God can create this second mind without an attendent physical world, which means that the mind is simply wrong about it being in harmony despite having all the same reasons you do to have to believe that it is in harmony. If it's impossible for a single world, even an uncountably infinite one, to contain all minds, then the overwhelming majority of minds have no physical world to be harmonious with. Since you are no one special, this implies that you also have no harmony. You are simply given an arbitrary set of experiences by God in order to make every single possible mind exist.
If you believe (2) that God *can* give everyone a physical world through an infinitely large universe, why not posit an infinitely large universe with no God?
3. There's some sense in which most of the people are not created in a non-inductive world.
Sure. I'm not relying on the "0.9*infinity = 0.1*infinity" trick. I'm relying on the exact same argument against modal nonsense that you made in your other blog post! You answered this argument there. I have yet to see how you extracrate your "God creates all possible minds argment" from your "if all possible things are created induction fails" argument. It seems impossibl. If induction fails without god, what does God making every conceivable thing add to make induction still work?
BUT, I don't think you're right even if I ignored your previous writings. You say that even if every super unlikily event does happen, most people will experience normal things, so the probabilities stay the same. I don't think your argument in this post supports this.
Take the poker example. You are about to check a card you have been dealt. The card could clearly be one of the 52 normal playing cards. God would create one person who experienced seeing each of the regular cards. Now let's imagine a 47 of clubs. Presumably God would also create a person who, by magic, drew a 47 of clubs. *Crucially*, God would not have to create 10^1000 copies of the person who drew the normal card in order to justify the extreme odds of a person pulling a non-standard card by magic. God doesn't roll dice to create people, he just makes all he possible people.
So God creates exactly 1 person who draws a 3 of clubs, and exactly one person who drws a 333 of clubs. Logically, your chances of drawing a 333 of clubs are the same as the chances of drawing a 3 of clubs. Induction fails!
4. Something feels off about your argument, but I can't quite put my finger on it. However, let's assume you are correct. We must be extremely specific about the language. A priori, any particuliar mind could be "The only one that ***must*** exist". Super duper emphasis on "must" exist. As I just said, this is your statement, and it is correct.
So the chances of your mind being the the only necessary mind are very very low. The thing is, once you reflect on the fact that you exist because you are reflecting, that is incontrovertible evidence that *your* mind is in fact the mind that must exist. There is literally infinite evidence that your own mind exist. This trounces the extremely low prior. It's like choosing a random number and getting 165,004. Sure, that number is exceptionally unlikily to be chosen, but its just factually the number you got.
Seems like any argument to the contrary has to be an argument in favor of your own nonexistence...
Conclusion: You are the only mind that necessarily exists!
I've recently been thinking about how SIA manages to add up to normality in Doomsday argument while otherwise leading to the conclusion that all possible people and therefore God exist and got a bit confused. I would appreciate if you clear this one for me.
In Doomsday argument, according to SIA, first you learn that you exist at all and then you learn that you exist at a specific place among all existent people. First update moves you towards thinking that more people are likelier than less and the second update exactly compensates it, therefore P(Doom) = P(!Doom).
So why doesn't the same principle apply here? When I just learn that I exist, without knowing my number I update in favor of all people existing, and, by your logic, God existing as well, but only until I learn that my number is somewhere around 60 billion, after this I should be indifferent between more people and less people, should I not?
Is it that upon learning that I exist under SIA I become so confident that there are infinite people, that I do not actually believe that I'm among the first 60 billion even when told and shown all the archeological data? That I'm already extremely sure that there is a multiverse/aliens/other dimensions/simulations, so no fact about the number of humans on planet Earth can actually move my credence?
1. If the class of people is a proper class (too large to be a set), then it won't form a measure space, and you won't be able to use it in Bayesian reasoning.
2. Even if you get around this: suppose for each subset of people there is a possible person thinking about them. This would predict, with probability 1, that you are thinking about infinitely many people. If you are thinking about finitely many people then this observation would disconfirm the theory. This is going to be a problem however you argue for an infinite cardinality of people (even for countably many people). Say there are countably infinite brain states. Then, with probability 1, a randomly chosen brain will have more neurons than there are particles in our universe. And the theory is disconfirmed by the fact that my brain is smaller than that.
3. (I'm not sure about this one) One need not reject the SIA. Suppose one is a necessatarian, or favors branching modality, or (like me) is a modal anti-realist. Then they can accept something like the SIA (in my case SIA is meaningless) but not have a reason to favor theories which predict more people.
You posted this on Reddit (r/debateanathiest) and it got torn apart and thoroughly debunked. (I'm assuming, based on the fact that you didn't respond to any of the arguments, that you no answer for them)
Maybe you should revisit this terrible argument.
(And don't be so dishonest as to post on a debate forum and avoid debate)
Hi! I stumbled upon this while reading about SIA, and I'm very surprised by your assumption that truths (or sets) and minds can be put in a one-to-one correspondence:
1. There are good reasons to think that not all truths are knowable: see Fitch's paradox (https://plato.stanford.edu/entries/fitch-paradox/). It could be the case than almost all truths are unknowable and don't correspond to any mind.
2. There are numerous results in mathematics about there being only countably many objects one can reasonably think about. For example, there are only countably many computable real numbers, or definable integer sequences. Likewise, there are only countably many propositions we can express in a formal language, because their statements are finite.
Now, you might object that it doesn't mean those undefinable propositions are unthinkable of. But I don't see an argument for why they must be thinkable of either. I myself can only think of reasonably "finite" objects. I can't conceive of a mind thinking about some undefinable proposition or some weird incredibly large set.
3. Even if there are minds capable of thinking about absurdly large infinities, I don't see why there should be a one-to-one correspondence between them and all truths. It seems like you're confusing "a mind that is capable of thinking about T existing" and "a mind being in a state of thinking about T". Maybe there's some supermind that is capable of thinking of any truth, but there's only one such mind. You'd have to postulate something bizarre like possible minds that are only capable of thinking of a single particular truth for a one-to-one correspondence to exist.
Of course, this leaves other arguments about there being at least Beth 2 minds, I haven't investigated those.
1. Well a theist should think that every possible truth is, in fact, known. I'll have to think more about this.
2. If you accept omniscience is possible then you'll think those tings are knowable.
3. I think you could have a mind thinking about each specific truth. Seems possible. I guess I don't really see the puzzle here--why think it's impossible that for each truth, there's a mind thinking about only that?
1 & 2 seems premature if this is your argument for the existence of God.
3. In another thread you reply that:
>He creates all possible people but that doesn't mean he creates people in every state, so he probably doesn't make many Boltzmann brains, if any
I feel like "a mind in a state of being a boltzmann brain" and "a mind in a state of thinking about some truth" is symmetric. Why won't there be minds that are only capable of being Boltzmann brains?
>why think it's impossible that for each truth, there's a mind thinking about only that?
I'm not sure if it's either possible or impossible, but I don't have arguments for why it's possible. I can imagine a mind in a state of thinking about some truth, but not a mind that can only think about a particular truth.
If God creates all possible people, does this mean that He also creates Boltzmann Brains and Brains-In-Vats? Or are Boltzmann Brains and Brains-In-Vats only possible people when there is no God?
Consider universal reconciliation: all created people shall be saved. If universal reconciliation is true, then while we have an answer to anti-natalism, what is the answer to the question: why not procreate as much as possible even if we cannot take care of the children? Or if life begins at conception, then why not have as many abortions are possible since all created people will be saved including the aborted?
I think the anthropic argument does answer these questions. Suppose that Jane is an only child and dies a virgin. She dies having no siblings and no children. If God created all possible people, then all of Jane's brothers and sisters and children do exist and will all be saved. So we don't need to procreate as much as possible to ensure that as many souls as possible will enjoy Heaven.
He creates all possible people but that doesn't mean he creates people in every state, so he probably doesn't make many Boltzmann brains, if any. There's no reason to maximize procreation because people will exist somewhere even if you don't make them
Has anybody suggested the Fermi Paradox as evidence for Theism? On Naturalism, we'd expect the universe to be full of life eons older than us and there to be abundant evidence of extraterrestrials. On Theism, humans are something special and created by God outside the normal material order and we shouldn't be surprised if it's only us.
Douglas Adams has a wonderful puddle analogy against the fine-tuning argument: if you change the shape of the puddle hole, the water will change shape accordingly. In other words, according to Adams, the world wasn't made for us; we evolved to adapt to the world.
But the puddle analogy doesn't work when it comes to the Fermi Paradox. Where are all the aliens? Why isn't evolution taking place all over the place? On the moon? On the other planets?
If aliens were everywhere in the universe, nontheists won't believe that God created the universe for life. Instead they would apply the puddle analogy to the entire universe.
Thank You, I really enjoyed seeing a strong novel argument for the existence of God!
1. Why can’t you use the same style argument for modal realism, our world is extremely complex and seems arbitrary, if modal realism is true than we should expect a world like ours to exist, if modal realism is false than the probability of our world existing out of all possible worlds is null, so must be modal realism is correct?
2. Dose the argument still work if you use a measure of complexity to assign prior probabilities, more complex people (power set) would have a substantially lower prior probability which should significantly raise the probability of you existing. (Although I have no idea how to model the complexity of elements within an uncountable infinite set)?
God doesn't have to make all possible humans. He just has to make some humans right?
Are you saying that all the possible humans are created in this world? Or are many in a multiverse elsewhere?
Naturalist multiverse models also do the trick right? Many world's interpretation of QM would predict the data that you exist, even more than theism maybe bcz there would be multiple copies of you.
Hi Matthew, interesting flurry of writings here. I have been skimming through them, and don't find myself particularly moved in the theistic direction (I have always been agnostic leaning, but I think your agnosticism is quite different from mine).
A basic question: couldn't several of these arguments (this article and others) work if the word "God" were replaced with "creator"?
It would need to be a creator with a desire to make all possible people powerful enough to create all possible people--too many to be part of any set. But yes. Though there aren't other creators like that which are good simple candidates.
An agent can create something for a purpose. So theism doesn't require that every possible thing be created, merely that every thing that is created furthers the overall purpose.
I don't think that all humans have to be constructed. But under theism, there exists one or more agents who could choose for the humans that are constructed to form.
It is common to forget that when dealing with theism, you are positing an agent who can choose how things are. Agents are agents because they can optimize, choosing the right tool for the right job to create the right thing at the right time in the right place. If you exist, it is for a reason.
Apologies for the late post. But I found this argument fascinating and wanted to share my thoughts. Also sorry to see the reception you got on the reddit page. I took a peek at the comments, and they seemed especially dull and mean-spirited. Just a reminder of how much we should cherish philosophical blogs like these I suppose!
Before I get into the meat of your argument, let me make a minor quibble about your points that there is no set of possible observers (the observer reference class is greater than Beth 2):
1. As mentioned already in the comments, not all truths are knowable. So it seems dubious that truths can be put in 1-to-1 correspondence with observers.
2. This assumes that infinite minds count in the set of possible observers. But maybe it doesn't make sense to include such minds in the reference class of possible observers one can be. If so, then (assuming every mind is decomposable into a computational structure with finite parts), we won't be able to construct a diagonal proof showing that there is a mind not in the set of all possible observer-minds, since that mind would have to be describable by a real number (i.e. infinite).
Now into the meat of the argument:
A) It seems to me that there is a lacuna in your argument which has to do with the construction of one's reference class. Endorsing SIA doesn't obviate the need for constructing a reference class, since we still need to define what we think an observer is. Reasonable people can disagree about what constitutes an observer. Particularly, if we accept SIA then we accept that we should reason as if we were sampled from the reference class of all possible observers we could have been. But what constitutes an observer that "we could have been"? Maybe a physicalist might argue that an observer can only be a physical entity which is composed of some finite computational structure (related to point 2 above). It could also be argued that we should only consider ourselves to belong in the reference class of entities which could be physically constructed according to possible natural theories. If so, then hypothetical entities in the Beth 2 realm won't count as observers. And the multiverse counter still goes through.
B) It's not clear to me that atheism is incompatible with Beth 2 worlds. Just because we reject theism doesn't mean we have to accept some common naturalistic alternative (e.g. multiverse theory). Maybe there exists some metaphysical principle (e.g. simpler patterns reproduce into complex repeatable patterns) which governs the construction of worlds, and which entails that there will exist uncountably infinite number of worlds where induction is sound, and little to no worlds where induction is falsified. I don't see why our prior for such a principle must be lower than our prior for theism.
Alternatively, one could simply accept the existence of Beth-2 observers in uncountable number of worlds as a brute fact. One presumably has to endorse a brute fact at some stage (whether God or something else). So the atheist can simply say that they take on a brute fact one step sooner in the explanatory chain. Perhaps this could be retorted with appeals to simplicity (similar to Swinburne's cosmological argument), so that accepting a simpler explanation (i.e. God) as a brute fact is easier. However, I find such arguments really dubious. It's not clear to me that there are metaphysical reasons to favor simplicity. Maybe there are physical reasons to favor simplicity (our universe is constructed such that simpler theories will be more likely to be true), but why should we think that the success of simplicity in the physical world is explained by the existence of a metaphysical rule in favor of simplicity which applies to cases outside our physical universe?
C) I think the reliance on infinite classes is problematic for the argument here. Infinity is especially tricky, as evidenced by cases like the measure problem and Pascal mugging. The problem with infinites in general suggests to me that the real trouble in such cases is that anthropic reasoning in ordinary cases is not equipped to handle infinites, and we need to make modifications like introducing cutoff thresholds (e.g. regularization).
Just as an example. Suppose I told you that I was an interdimensional being who had been in contact with a superintelligence that had discovered a new physical theory which predicted some staggering super-infinite class of observers but also predicted that theism was false. For simplicity, let's just say that this super-infinite class of observers was larger than Beth omega.
Now obviously you aren't going to believe me. But presumably you should assign some vanishingly small, but still finite, prior credence that what I say is true. But now given the insane posterior shift advantage that my theory, if true, would accrue over the theistic theory, it seems that you must endorse my theory.
I think what this reveals is that we simply can't naively reason on infinities in anthropic cases as we would ordinarily do; we need some cutoff value somewhere. But once we introduce a cutoff value, nothing stops the atheist from asserting that the increase in possible observers from aleph-null to Beth-2 goes beyond the cutoff, and thus does not affect the posterior shift in any way. Hence, theism need not be more probable than multiverse theory.
No worries about the late post--thanks for the engagement.
//1. As mentioned already in the comments, not all truths are knowable. So it seems dubious that truths can be put in 1-to-1 correspondence with observers.//
Right so we should modify the principle to be that truths that don't reference themselves being unknown can be put into correspondence with observers.
I don't understand the second point.
In regards to A) The reference class of SIA is the share of observers who one might be currently given their evidence. So I have a reason to think that there are more identical earths because I could right now be on any one of them. There are also Beth 2 possible physically creatable observers--the proof there's no set of observers would show there are more than Beth 2--the Beth 2 proof is different and more modest.
B) It's possible that there are Beth 2 worlds. But it's naturally predicted by theism and absurdly unlikely on atheism. I think theism should have a higher prior than this world because it's very simple, supported by other evidence, and most of all, there is no coherent theory of what the other world is supposed to be like. A physical multiverse theory (in the sense described here https://capturingchristianity.com/why-god-exists-fine-tuning-beauty-and-discoverability/) won't do the trick, especially if there are unsetly many people, and a metaphysical multiverse theory undermines induction by making there be many worlds where induction doesn't work.
You could posit that there are just Beth 2 different worlds for no reason, but that's extremely arbitrary and ad hoc, and furthermore is infinitely complicated because it posits an infinite number of disconnected fundamental things. If there aren't metaphysical reasons to favor simplicity it's hard to see why you should trust induction because there are a lot of ways that reality could stop working one second from now.
C) Yeah infinity is tricky but I feel like I'm using it in a pretty germane way here. Infinity is the least suspicious when there's some pattern that holds in finite cases and you just extrapolate it to the infinite cases. So more people existing is more likely in finite cases (and can be shown to be in infinite cases for similar reasons). It would be really weird if there was a random break in the reference class at infinite people. Furthermore, I think this runs affoul of the arguments given here (in the contraception case, imagine Aleph Null people each creating Beth 2 more people https://benthams.substack.com/p/the-self-indication-assumption-works) and here https://benthams.substack.com/p/alternatives-to-sia-are-doomed (hopefully it should be clear how that would work in those cases, but happy to explain if you're not sure--also happy to discuss this more either on YouTube or discord--shoot me a dm if you want, my discord name is omnizoid).
Wow that was a really swift reply, thanks!
There's a lot to say here, so I'll try to keep my points as structured as possible.
A) Let me start by tackling the discussion of reference classes. While I agree that SIA simplifies the selection of one's reference class in comparison to SSA, I don't think it solves the problem of reference class choice outright. The trouble is that one still needs a criterion method for what counts as an observer. People will have different intuitions as to who they 'could' have been (given their evidence). This will be based on things like their theory of personal identity and so forth. Should we take into account lesser conscious beings (does it make sense to say that one could have been a slug?). Non-conscious observers (as Schwitzgebel argues here: https://eschwitz.substack.com/p/neurons-arent-special-a-copernican, see the comment chain with our discussion)? Non-physical ectoplasmic soul stuff?
The point is that one needs a criteria method for adjudicating what counts as membership in the reference class of observers, and what does not. Once you admit this, there is reasonable room to disagree as to what the criteria should be. I think the non-theist has room here to argue that we should only take into consideration those beings who could have been created by natural theories of physics. So hypothetical Beth 2 conscious entities in the metaphysical multiverse won't count as observers on this view. Perhaps it could be objected that this membership criterion is ad hoc, but the challenge is in showing any membership criterion which won't seem ad hoc to another person (for instance, I noticed that your membership criteria only takes into account physical entities, and so excludes ectoplasmic conscious souls). Moreover, the atheist could retort that they have good evidence for selecting their membership criteria, namely the physical evidence on hand governing the theory of universe formation.
B) What I had in mind here was a metaphysical multiverse theory where modal realism was false. That's what I was trying to get at with my talk of a metaphysical principle where coherent structural patterns (e.g. brain, universes) are more likely to be created from simpler patterns than non-coherent patterns. Maybe the atheist could endorse such a principle, which would permit the existence of Beth 2 observers in mostly induction friendly universe. I don't want to push this point too hard because this will depend on your priors for theism versus such a metaphysical principle. If you say you have other evidence for theism, then fair enough. The point is that atheists might reasonably disagree though if their priors were different.
About the brute fact stuff. The simplicity issue is complicated but worth discussing because I find that it is so central to theist arguments for God (like Swinburne's cosmological argument). I'll leave this for the end though (see my note below). I assume in the meantime that you agree with me that the objection to be made here is that theism should be preferred as a brute fact explanation because it is simpler (if that's not the case let me know!).
C) I agree that in general extrapolating to simple infinity cases is okay unless one has a defeater. But the point of my inter-dimensional thought experiment was to demonstrate just such a defeater, and why we shouldn't extrapolate in anthropic cases. I didn't really see a response to that point. You mentioned that it would be weird and arbitrary if there was a random break in the reference class at infinity, two points in response:
1- It doesn't have to be a discrete break. Depending on how one conducts regularization one could structure one's probabilities so that each successive observer in one's reference class shifted your posterior by a lesser amount, so it reached a limit at infinity of zero posterior shift.
2- I find the talk of weirdness itself rather strange. I think it's only weird if we adopted something like a frequentist probabilistic approach, and thought that there were objective probabilities. But if probabilities are subjective and Bayesian, as we are assuming, all we are concerned with is what our frame of mind should be. Given this, I don't think it's weird at all to posit that anthropic probabilities break down at infinity. All that indicates is that our minds are not equipped to handle such infinities using the same tools we use to handle finite cases, and that's hardly surprising.
About your posts, I'm not sure what the argument is here but yes obviously the proponent of an infinite cutoff would have to accept that Aleph null people creating Beth 2 more people does not raise one's probabilities of being born. That's just a straightforward consequence of what an infinite cutoff entails, not really sure how that's supposed to be an argument against? Perhaps your second post about the weird consequences of rejecting SIA was intended as the argument? But I think the proponent of the infinite cutoff doesn't have to accept weird effects like the doomsday argument or the Adam and Eve acausal powers, supposing that the finite pool of possible observers were still large enough to offset such effects (e.g. one's birth rank being unusual).
Note on simplicity:
I brought up this argument before in an email with Brian Cutter concerning his paper on Nomological harmony (https://philarchive.org/rec/CUTTPO-9), but basically I think theistic reliance on simplicity runs afoul of a nominalist objection. If you're a mathematical nominalist (as I am), then you think definitions of simplicity (e.g. Kolmogorov complexity) will just describe the behavior of particular physical patterns in our universe, and not some deep metaphysical law about the nature of algorithms. But once we accept this, then there's no reason to think that simplicity considerations will apply to metaphysical structures and patterns not governed by our physical laws. So arguments about theistic simplicity are rather dubious on this view, since there's no reason to think that metaphysical structures like God would be governed by such rules.
You do raise the point that we have no grounds for inductive reasoning if metaphysical simplicity is false. But:
1) You could believe in inductive reliability on separate grounds from simplicity, e.g. theism, if one had independent evidence outside of simplicity considerations, or that metaphysical principle I was talking about, or whatever.
2) My above point applies. It's unclear to me how to assign our priors to such scenarios, and whether we should favor a random universe as more likely over a simple patterned one. It's true that most structured algorithms are random as opposed to simple patterns, but for the nominalist, talk of possible algorithms just refers to particular physical behaviors. It happens to be the case that the combinatoric states of physical structures in our universe are such that the random physically possible states (for example, possible states that a random number generator can be in) greatly outnumber the simple patterned states, but perhaps this doesn't apply to other metaphysical structures. Perhaps the metaphysical patterns which govern universe creation don't obey the normal algorithmic rules. In which case, we don't need simplicity considerations to justify our belief that we exist in a well-governed universe (they may just be more likely than random universes).
Hope this all made sense.
P.S. I am busy writing a solution paper to the hard problem of consciousness at the moment, so I might not be able to continue the discussion right away (or make a reply here for that matter), but I'm happy to take you up on your offer for a discord discussion in the near future if you want to continue. Thanks for the offer.
Yes, happy to continue the conversation over discord.
A) You don't need to adjudicate what could *have been* you. You need to adjudicate what currently might be you. I know I'm currently not a bug and that I'm currently not a guy named John in Kansas, so I have no anthropic grounds to think there are more bugs or guys in Kansas. On SIA it doesn't matter how you construe the reference class. For instance, suppose you include bugs and there are 10 times as many bugs as people. Then your existence becomes 10 times as likely but the probability that you'd exist as a person is 1/10 as great, so they exactly cancel each other out. Thus, on SIA the only thing that matters is how many people there are who you currently might be.
B) The problem is that there is no viable metaphysical multiverse model. To have a viable metaphysical multiverse be simple, you have to think that there is some fundamental thing that is instantiated without limit (that's pretty much the definition of a metaphysical multiverse). But there aren't that many fundamental things: they basically are value, math, modality, and beauty maybe. Math unlimited is the Tegmark thing that undermines induction, modality unlimited is modal realism which undermines induction, consciousness unlimited is unclear but maybe either theism or something that undermines induction (if all experiences are instantiated, most of them will have deficient induction), and beauty unlimited would just have a single beautiful thing.
C1) If you shift your posterior by less as there get to be more agents, then the argument I link to surrounding the generalized doomsday argument means that has absurd results in cases with a finite number of observers. In the Adam and Eve case, for instance, where they find out their birth rank, they can predict with very high confidence, in advance, that a poker game will have a royal flush, and get all sorts of other abberant predictions and causation https://benthams.substack.com/p/several-new-arguments-for-the-self?utm_source=publication-search
C2) It's weird for probability to have a discrete break at infinity in this case. To illustrate, imagine that you adopted SIA up to 650 people and then thought it stopped working. That would be weird. Even if you're a Bayesian, sometimes there's a principled reason to assign probabilities to things--e.g. you should think that a coinflip has a probability of .5 of coming up heads, all else equal.
I think the view does have to accept the doomsday argument and other stuff in the infinite case. Imagine that aleph null people are created and then a game of poker will be played. If it gets a royal flush, no extra people are created. If it gets anything else, Beth 2 people are created. Suppose you exist but don't know if you're one of the aleph null people originally or the later Beth 2 people. You reason in the following way: if Beth 2 people are such as to be created (this is the tenseless proposition that whenever the game is played it will have something other than a royal flush), the odds that I'd be one of the first aleph null people are 0--aleph null/Beth 2. Then you find out that you are one of the first aleph null people. Now you can predict in advance that a poker game that hasn't been played yet will have a royal flush based purely on its future consequences, which is clearly illicit and violates certain obvious features of probability https://benthams.substack.com/p/against-biting-the-bullet-on-adam.
One could make a similar argument for the contraception case, for the record.
Re induction and simplicity:
1) You could, but then because theism is a very specific way for reality to be would have an absurdly low prior.
2) It's true that inductive universes can just be likelier than other ones. But ideally we want an explanation of that, and induction working would explain that. If you just say, well maybe there's some explanation of induction other than simplicity that explains it, that's possible, but it just seems really unlikely. It also seems hard, on such a picture, to see why we should assign a low probability to random other stuff existing, like a particular type of particle.
Thanks for the thoughtful engagement! Interesting thoughts!
1. This would also seem to support the evil god hypothesis. If there's only a 1% chance that a good god would create everyone, there seems to be an equal chance that anti-nataliss are right and that there's a 1% chace of an evil god creating everyone as well.
2. This argument defeats psychophysical harmony. If God creates infinite minds, then presumably he will create many minds that are not psychophysically harmonious, and many more which cannot tell the difference. What's to say that you and I are not one of those minds? However, if God really does create every possible mind in a way that's harmonious, then it's unclear why an infinite material universe couldn't do the same. If an infinite universe cannot, why can a (logically constrained) God do so? (Actually this latter point also seems convincing. If there is "no set of all truths" in logic, why can God make one. Are you arguing for some sort of divine transcendence of logic?).
3. This argument seems to also defeat induction in the same way that modal realism does. If an infinite number of actually created minds exists, then surely there are an infinite number of minds where induction spontaniously breaks down, and everything around them turns into cantelopes.
4. One atheist account that solves this argument is to deny that there are other minds exist at all. There is only one possible mind, and it is the mind that is currently experiencing. :P
1. Yep.
2. Nope, the evidence is that I, in particular, have a harmonious soul, which is not explained by the fact that I exist.
3. Nope, not any more than the fact that in Hilbert's hotel the same number of people get a royal flush as get a pair means that in the hotel I should think I'll be as likely to get a pair as a royal flush.
4. But the odds that my mind, in particular, would be the only possible mind, when it has no special claim to hat relative to the other conceivable minds, is zero.
2. But if this argument is correct, then you have no way of knowing you in fact have a harminous soul! You could be one of those utterly infinite not-a-set-because-no-set-can-contain-them of minds that experiences things totally disconnected from physical reality. How would one prove that this is not the case?
3. I think this passage from an acquantence of mine answers this argument quite well:
"There are people exactly like me up until this point—and for an infinite number of them, induction fails one second later. Induction, for those that don’t know, is the idea that the future will be like the past, that the fundamental laws of the universe won’t spontaneously break down one second from now, that the sun will rise tomorrow. But for every possible world in which induction works, there are innumerable ones in which it does not."
Is the same thing not true here? If God creates every mind, then there are presumably an infinite number of minds that had the exact same experiences as you, but which then experience something totally random one second from now. In fact, the overwhelming majority of minds that experienced the same things as you will suddenly experience something whacky occur.
So Hilbert's hotel doesn't really work. Firstly, there are far more minds then the mere countable infinity of rooms in the hotel, so the analogy is imperfect. If every mind is created it would be like everyone recieving a poker hand, and then 99.99999%+ of people get a hand that includes cards outside the standard deck. (We can imagine an eleven of clubs, a fifteen of spades, and so on). Seems like you would be a fool to believe you would get an ordinary card, despite induction!
4. Your mind is special -- it's the only mind that must exist. It's entirely possible that there are no other minds. Seems pretty special to me!
2. I do. I observe my mental states are not random static.
3. See the Hilbert's hotel example. There's some sense in which most of the people are not created in a non-inductive world. If each of infinite people has some event happen with 90% probability and another with 10% probability, while the total number of events is the same, my credence in the 90% probability event happening should be 90%.
4. But a priori any particular mind could be the only one that must exist. You assign priors before observing special facts about your mind.
> 2. I do. I observe my mental states are not random static.
You observe that you have mental states. You have no way of knowing that these mental states actually correlate with some external reality.
According to you there exists a mind that has the exact same quality of experiences as you. Now maybe they're not exactly you, but they generally speaking have all the same reasons to believe in psychophysical harmony through observation of their own experiences.
Your problem is that you hold either (1) God can create this second mind without an attendent physical world, which means that the mind is simply wrong about it being in harmony despite having all the same reasons you do to have to believe that it is in harmony. If it's impossible for a single world, even an uncountably infinite one, to contain all minds, then the overwhelming majority of minds have no physical world to be harmonious with. Since you are no one special, this implies that you also have no harmony. You are simply given an arbitrary set of experiences by God in order to make every single possible mind exist.
If you believe (2) that God *can* give everyone a physical world through an infinitely large universe, why not posit an infinitely large universe with no God?
3. There's some sense in which most of the people are not created in a non-inductive world.
Sure. I'm not relying on the "0.9*infinity = 0.1*infinity" trick. I'm relying on the exact same argument against modal nonsense that you made in your other blog post! You answered this argument there. I have yet to see how you extracrate your "God creates all possible minds argment" from your "if all possible things are created induction fails" argument. It seems impossibl. If induction fails without god, what does God making every conceivable thing add to make induction still work?
BUT, I don't think you're right even if I ignored your previous writings. You say that even if every super unlikily event does happen, most people will experience normal things, so the probabilities stay the same. I don't think your argument in this post supports this.
Take the poker example. You are about to check a card you have been dealt. The card could clearly be one of the 52 normal playing cards. God would create one person who experienced seeing each of the regular cards. Now let's imagine a 47 of clubs. Presumably God would also create a person who, by magic, drew a 47 of clubs. *Crucially*, God would not have to create 10^1000 copies of the person who drew the normal card in order to justify the extreme odds of a person pulling a non-standard card by magic. God doesn't roll dice to create people, he just makes all he possible people.
So God creates exactly 1 person who draws a 3 of clubs, and exactly one person who drws a 333 of clubs. Logically, your chances of drawing a 333 of clubs are the same as the chances of drawing a 3 of clubs. Induction fails!
4. Something feels off about your argument, but I can't quite put my finger on it. However, let's assume you are correct. We must be extremely specific about the language. A priori, any particuliar mind could be "The only one that ***must*** exist". Super duper emphasis on "must" exist. As I just said, this is your statement, and it is correct.
So the chances of your mind being the the only necessary mind are very very low. The thing is, once you reflect on the fact that you exist because you are reflecting, that is incontrovertible evidence that *your* mind is in fact the mind that must exist. There is literally infinite evidence that your own mind exist. This trounces the extremely low prior. It's like choosing a random number and getting 165,004. Sure, that number is exceptionally unlikily to be chosen, but its just factually the number you got.
Seems like any argument to the contrary has to be an argument in favor of your own nonexistence...
Conclusion: You are the only mind that necessarily exists!
I've recently been thinking about how SIA manages to add up to normality in Doomsday argument while otherwise leading to the conclusion that all possible people and therefore God exist and got a bit confused. I would appreciate if you clear this one for me.
In Doomsday argument, according to SIA, first you learn that you exist at all and then you learn that you exist at a specific place among all existent people. First update moves you towards thinking that more people are likelier than less and the second update exactly compensates it, therefore P(Doom) = P(!Doom).
So why doesn't the same principle apply here? When I just learn that I exist, without knowing my number I update in favor of all people existing, and, by your logic, God existing as well, but only until I learn that my number is somewhere around 60 billion, after this I should be indifferent between more people and less people, should I not?
Is it that upon learning that I exist under SIA I become so confident that there are infinite people, that I do not actually believe that I'm among the first 60 billion even when told and shown all the archeological data? That I'm already extremely sure that there is a multiverse/aliens/other dimensions/simulations, so no fact about the number of humans on planet Earth can actually move my credence?
Some thoughts:
1. If the class of people is a proper class (too large to be a set), then it won't form a measure space, and you won't be able to use it in Bayesian reasoning.
2. Even if you get around this: suppose for each subset of people there is a possible person thinking about them. This would predict, with probability 1, that you are thinking about infinitely many people. If you are thinking about finitely many people then this observation would disconfirm the theory. This is going to be a problem however you argue for an infinite cardinality of people (even for countably many people). Say there are countably infinite brain states. Then, with probability 1, a randomly chosen brain will have more neurons than there are particles in our universe. And the theory is disconfirmed by the fact that my brain is smaller than that.
3. (I'm not sure about this one) One need not reject the SIA. Suppose one is a necessatarian, or favors branching modality, or (like me) is a modal anti-realist. Then they can accept something like the SIA (in my case SIA is meaningless) but not have a reason to favor theories which predict more people.
You posted this on Reddit (r/debateanathiest) and it got torn apart and thoroughly debunked. (I'm assuming, based on the fact that you didn't respond to any of the arguments, that you no answer for them)
Maybe you should revisit this terrible argument.
(And don't be so dishonest as to post on a debate forum and avoid debate)
Haha, I totally forgot that I'd done that--I'll respond now.
Hi! I stumbled upon this while reading about SIA, and I'm very surprised by your assumption that truths (or sets) and minds can be put in a one-to-one correspondence:
1. There are good reasons to think that not all truths are knowable: see Fitch's paradox (https://plato.stanford.edu/entries/fitch-paradox/). It could be the case than almost all truths are unknowable and don't correspond to any mind.
2. There are numerous results in mathematics about there being only countably many objects one can reasonably think about. For example, there are only countably many computable real numbers, or definable integer sequences. Likewise, there are only countably many propositions we can express in a formal language, because their statements are finite.
Now, you might object that it doesn't mean those undefinable propositions are unthinkable of. But I don't see an argument for why they must be thinkable of either. I myself can only think of reasonably "finite" objects. I can't conceive of a mind thinking about some undefinable proposition or some weird incredibly large set.
3. Even if there are minds capable of thinking about absurdly large infinities, I don't see why there should be a one-to-one correspondence between them and all truths. It seems like you're confusing "a mind that is capable of thinking about T existing" and "a mind being in a state of thinking about T". Maybe there's some supermind that is capable of thinking of any truth, but there's only one such mind. You'd have to postulate something bizarre like possible minds that are only capable of thinking of a single particular truth for a one-to-one correspondence to exist.
Of course, this leaves other arguments about there being at least Beth 2 minds, I haven't investigated those.
1. Well a theist should think that every possible truth is, in fact, known. I'll have to think more about this.
2. If you accept omniscience is possible then you'll think those tings are knowable.
3. I think you could have a mind thinking about each specific truth. Seems possible. I guess I don't really see the puzzle here--why think it's impossible that for each truth, there's a mind thinking about only that?
1 & 2 seems premature if this is your argument for the existence of God.
3. In another thread you reply that:
>He creates all possible people but that doesn't mean he creates people in every state, so he probably doesn't make many Boltzmann brains, if any
I feel like "a mind in a state of being a boltzmann brain" and "a mind in a state of thinking about some truth" is symmetric. Why won't there be minds that are only capable of being Boltzmann brains?
>why think it's impossible that for each truth, there's a mind thinking about only that?
I'm not sure if it's either possible or impossible, but I don't have arguments for why it's possible. I can imagine a mind in a state of thinking about some truth, but not a mind that can only think about a particular truth.
I need help with this argument.
If God creates all possible people, does this mean that He also creates Boltzmann Brains and Brains-In-Vats? Or are Boltzmann Brains and Brains-In-Vats only possible people when there is no God?
Consider universal reconciliation: all created people shall be saved. If universal reconciliation is true, then while we have an answer to anti-natalism, what is the answer to the question: why not procreate as much as possible even if we cannot take care of the children? Or if life begins at conception, then why not have as many abortions are possible since all created people will be saved including the aborted?
I think the anthropic argument does answer these questions. Suppose that Jane is an only child and dies a virgin. She dies having no siblings and no children. If God created all possible people, then all of Jane's brothers and sisters and children do exist and will all be saved. So we don't need to procreate as much as possible to ensure that as many souls as possible will enjoy Heaven.
He creates all possible people but that doesn't mean he creates people in every state, so he probably doesn't make many Boltzmann brains, if any. There's no reason to maximize procreation because people will exist somewhere even if you don't make them
Has anybody suggested the Fermi Paradox as evidence for Theism? On Naturalism, we'd expect the universe to be full of life eons older than us and there to be abundant evidence of extraterrestrials. On Theism, humans are something special and created by God outside the normal material order and we shouldn't be surprised if it's only us.
No though that's sort of similar to our case for why SSAers should be theists too.
Yes, the Fermi Paradox helps the Fine-Tuning argument. David H Bailey has a neat article about it: https://mathscholar.org/2017/11/fine-tuning-and-fermis-paradox/
The Rare Earth Hypothesis is one answer to the Fermi Paradox: https://en.wikipedia.org/wiki/Rare_Earth_hypothesis
Kenneth Samples discusses the Rare Earth Hypothesis as evidence for Theism: https://reasons.org/explore/blogs/reflections/scientific-discovery-and-god-planet-earth-part-3
Douglas Adams has a wonderful puddle analogy against the fine-tuning argument: if you change the shape of the puddle hole, the water will change shape accordingly. In other words, according to Adams, the world wasn't made for us; we evolved to adapt to the world.
But the puddle analogy doesn't work when it comes to the Fermi Paradox. Where are all the aliens? Why isn't evolution taking place all over the place? On the moon? On the other planets?
If aliens were everywhere in the universe, nontheists won't believe that God created the universe for life. Instead they would apply the puddle analogy to the entire universe.
Thank You, I really enjoyed seeing a strong novel argument for the existence of God!
1. Why can’t you use the same style argument for modal realism, our world is extremely complex and seems arbitrary, if modal realism is true than we should expect a world like ours to exist, if modal realism is false than the probability of our world existing out of all possible worlds is null, so must be modal realism is correct?
2. Dose the argument still work if you use a measure of complexity to assign prior probabilities, more complex people (power set) would have a substantially lower prior probability which should significantly raise the probability of you existing. (Although I have no idea how to model the complexity of elements within an uncountable infinite set)?
1, you can but modal realism is very improbable for reasons I explain in the article.
2. Yes because simplicity is about fundamental stuff, and theists posit only one fundamental person who is very simple.
God doesn't have to make all possible humans. He just has to make some humans right?
Are you saying that all the possible humans are created in this world? Or are many in a multiverse elsewhere?
Naturalist multiverse models also do the trick right? Many world's interpretation of QM would predict the data that you exist, even more than theism maybe bcz there would be multiple copies of you.
Nope, many worlds predicts only aleph null people, not Beth 2 or more.
Every possible human is made. Some just are elsewhere.
Hi Matthew, interesting flurry of writings here. I have been skimming through them, and don't find myself particularly moved in the theistic direction (I have always been agnostic leaning, but I think your agnosticism is quite different from mine).
A basic question: couldn't several of these arguments (this article and others) work if the word "God" were replaced with "creator"?
It would need to be a creator with a desire to make all possible people powerful enough to create all possible people--too many to be part of any set. But yes. Though there aren't other creators like that which are good simple candidates.
An agent can create something for a purpose. So theism doesn't require that every possible thing be created, merely that every thing that is created furthers the overall purpose.
I don't think that all humans have to be constructed. But under theism, there exists one or more agents who could choose for the humans that are constructed to form.
Huh? How does this address the argument? I'm not following.
It is common to forget that when dealing with theism, you are positing an agent who can choose how things are. Agents are agents because they can optimize, choosing the right tool for the right job to create the right thing at the right time in the right place. If you exist, it is for a reason.
Still not sure how this addresses the argument of the post.
I think (maybe), Riesland is trying to say that people have a unique purpose because God is trying to optimize, so god wouldn't create everyone.
Seems like a non sequitar, though.