Leaving aside questions of personal identity for a moment, quantum mechanics seems to very clearly exclude a notion of persistent identity for particles.
First, in the simple case where the amount and type of particles doesn't change, we can set up experiments where two multi-particle states are arrived at with opposite phase, and see if they interfere with each other. When the states differ only in the identity of the particles, we see that they do, so for example, "electron A in position X, electron B in position Y" can destructively interfere with "electron B in position X, electron A in position Y". Or it can interfere constructively, in which case each assignment of labels is equally valid.
Secondly, in the more fundamental theory of quantum fields, individual particles are just waves in those fields. Individual waves can have a meaningful kind of identity, if they don't interact too much with other waves, but in the general case waves can be created, destroyed, combine or split apart, or enter complicated interactions where you can't really pick out any waves any more at all, let alone identify "which" input wave they "really are". The situation in the simpler case arises because states are not distinguished by how they arose, only by the field value at each point, so "swapping" two identical particles is just the same state you started with.
This notion of fundamental identities also has a serious epistemological issue: if these identities don't effect any feature of the physical world, how could you possibly have learned of them? For example, you probably have an intuition that normally identities are persistent over time, but this intuition was not caused by you observing any physical event that demonstrates persistent identity because identity doesn't cause any physical events. So you would retain it even if, in truth, the identity of all trees on Earth were actually being shuffled every 6 hours, unless perhaps you also hold that God intervened to give you correct intuitions.
I think this sense that things have identities that persist over time independently of their physical state is just a cognitive shortcut humans use, which is approximately valid in our ordinary experience, but has no fundamental reality. Our experience involves lots of physically contiguous objects that don't change much over time, and don't often merge with, or split from, other objects of interest, and two previously distinct objects are almost never rendered physically identical in every way, so it's useful to think of objects as having a unique identity and associated history, but if you leave the ordinary experience this can quickly break down.
I don't really understand the physics, but even if particles don't actually persist over time, it's at least conceivable that they could. This means there are irreducible haecceities, which is all you need to get the argument off the ground (well, plus the other stuff).
I think that we are capable of intuiting true things even if the things we intuit don't explain features of our experience--e.g. moral facts.
I think it's a serious error to encounter a place where reality directly contradicts an intuition and insist that the intuition is still metaphysically correct because you can imagine it being true. Some things you can conceive of are just false, incoherent, logically contradictory, or metaphysically invalid, and looking at how the world actually works is one of the few ways to discover that.
Out of curiosity, where do you fall on A vs B theory of time? That's the other case I'm aware of, where physics gave a direct, and very counterintuitive, statement on a philosophical issue. Do you think our conscious experience of existing at a specific moment in time proves there is an objective present?
Can you explain what you're doing when you're conceiving 0 dimensional particles with no inner structure, size, or shape, but positive mass? What exactly is conceivable about Newtonian particles? Or are you conceiving something else by "particle?"
Correct, BB frequently makes declarations about science explaining the fundamental nature of reality, but has no clue about what the methodologies or findings of e.g. quantum physics are. He then makes an appeal from his intution about how widespread e.g. identity statements are and bakes in his presuppositions about how other fields of science use e.g. identity heuristics, and falsly claims that since his theory makes use of the same identity concept as scientific fields, his arguments gain extra epistemic virtue points.
I definitely don't think that, whatever your theory of complexity/simplicity is, hypotheses should be penalized for failing to specify haecceities, as opposed to just positing the existence of objects which bear certain relations between them but are otherwise "anonymous." I don't exactly even know what it would mean to specify a haecceity, other than to point ostensively to things around you and being like "that specific thing over there." And I don't think anyone grades the simplicity of a theory of physics based on pointing to anything, as opposed to its abstract mathematical character which would be the same even if you woke up in a black room with no memories and couldn't point to anything at all.
And I still don't really see how God is helping you here. First because it's not clear how God decides to create this electron instead of a different, indistinguishable electron, and second because your theory of what God does is going to have to build in all of his countless decisions to build this and that haecceity-specific electron in exactly the same way you accuse the atheist of needing to do. So the complex-due-to-haecceity theory of physics has been derived from something else, yes, but it's an equally complex theory of divine action.
I think most of your examples motivating haecceitism seem like they'd be easy to bite the bullet on for an anti-haecceitist - indeed, they are precisely sort of the paradigmatic cases meant to illustrate to novices what anti-haecceitism even means! It actually seems sort of common in metaphysics in general to argue that the existence of a symmetry implies the illusoriness of some intuitive metaphysical thing. For instance, a lot of people would be motivated to say that God couldn't have created the whole universe shifted five meters to the left of where it actually is (perhaps we need to pretend we live in a Newtonian universe for this to make sense, IDK), because what would be the real difference?
Finally, I've privately wondered if haecceity-centric viewpoints undercut SIA, or at least lead it to drastically different conclusions than it's usually taken to lead to. For example, in any of the standard red-vs.-blue jacket thought experiments, we're called to ask what the probability is of God's coin landing heads conditional on our observing ourselves having a red jacket - SIA says the answer is going to be based on the expected number of people who have such observations depending on coin outcomes. But if we instead ask what the probability is of God flipping heads conditional on ourselves observing *this specific* experience of a red jacket, then there's never going to be more than one of those in any world, no matter how many qualitatively identical observers there are. In other words, if SIA is based on computing the number of possible people who have my evidence, then no more than one person truly has *my* evidence in this sense.
1. To specify a haecceity, presumably you'd need a symbol of some sort attached to every haecceity to pick it out specifically, the same way I think you'd need for mental states.
2. The reason to think that we need to pick out the haecceities specifically is the same as the reason needed to pick out other facts.
3. God can pick which electrons he creates because he has a vivid mental grasp of every haecceity and picks which electron to make.
4. I think that God's decisions will follow from something deeper. You definitely don't want to just brutely build in all his decisions.
5. I have very different intuitions, especially about 3.
6. I don't think the point about SIA is right, because SIA gets off the ground if you just are uncertain about which of the haecceistic people you are--see Elga's proof https://benthams.substack.com/p/elga-proved-13
>1. To specify a haecceity, presumably you'd need a symbol of some sort attached to every haecceity to pick it out specifically, the same way I think you'd need for mental states.
This is saying God has a special mental symbol in his head that picks out a haecceity, for each such haecceity. OK, but how does he manage to do that? What sort of thing pops up in his mind so that symbol X ends up picking out electron haecceity A instead of qualitatively identical electron haecceity B? He's not merely imagining the electron's location, shape, charge, spin, or whatever, since none of these pick out the haecceity - so what's going on?
As usual with questions about "how does God do anything," I imagine the answer is just going to be posit that it's some sort of fundamental primitive. This is, to me, unsatisfying. And in this case, I don't even think I understand what's being suggested - I don't know what it means to have a direct mental representation of a particular haecceity, independent of having some way of referring to it ostensively. That is, *maybe* I can accept talk about my chair's haecceity in terms of "the haecceity of the thing that's impressing upon me such-and-such sensory perceptions," but if I counterfactually didn't have any those sensory perceptions, it feels nonsensical to imagine that I could think of my (actual) chair specifically. And this has nothing to do with needing an infinite number of representational symbols in my head - I don't think I have even one symbol that's like this, nor can I easily imagine what having such a symbol would be like subjectively.
>2. The reason to think that we need to pick out the haecceities specifically is the same as the reason needed to pick out other facts.
The problem is that I don't see in principle what a more or less simple explanation of haecceities is supposed to look like, on any theory, so it doesn't really make sense to take it into consideration here. How does theism predict that God wanted my hand to contain this specific electron instead of a qualitatively identical electron, without simply building that statement in as an additional posit? I know you suggest that you think there's some way to derive this from something simpler than merely building it in, but I'm having trouble seeing how this is supposed to work.
>6. I don't think the point about SIA is right, because SIA gets off the ground if you just are uncertain about which of the haecceistic people you are--see Elga's proof https://benthams.substack.com/p/elga-proved-13
I'm not saying this vitiates SIA per se, just that it drastically changes the answers that SIA outputs, essentially trivializing it so that the priors never change in response to anthropic reasoning. It's true that I can be uncertain about which person's experiences have the same haecceities as my own, but the number of possible people in any epistemically possible world whose experiences have this property is always exactly 1, and "the expected number of possible people in a world who have my evidence" is exactly what mediates updates in SIA.
So, for example, in the Sleeping Beauty case you refer me to here, haecceitistic SIA should recommend halving. If the coin landed heads, the expected number of observers across time who have *this* precise experience of waking up (as opposed to merely some similar experience of waking up) is 1. If the coin landed tails, the same thing is true. So, since the coin was fair, the posterior should also remain 1/2, and you should reject Elga's original thirder reasoning on the basis of SIA.
(You can get around all this by just building into SIA that you should ignore haecceities, but that seems to be the flavor of thing your post rejects.)
1. I don't get the problem. God has distinct thoughts about each haecceity. I don't think God is unique in this regard--a mind could easily have different thoughts about two qualitatively identical things.
2. God picks out the particular haecceities that he creates. On naturalism, to fully specify the world, you have to brutely build in the haecceities.
6. Well I think there would be nothing wrong with having SIA involve ignoring haecceities as, while real, they're not part of their evidence.
But you're not correct about what SIA implies if you take into account haecceities. The answer is exactly the same as if you ignore haecceities.
Analogy: a fair coin is flipped. If it comes up heads I'll wake up in a room with a particular shade of red wall. If it comes up tails, I'll wake up in that room, and then again in a room with a slightly different red wall shade. On SIA, after waking up and seeing a wall color of some sort, you should think that tails is twice as likely as heads because:
p(wall color 1)&heads=p(wall color 1)&tails=p(wall color 2)&tails.
Same basic idea applies to other SIA cases with haecceities. In this case, like the haecceities case, your evidence may be very specific, but it's specific in a way that you don't know about, so taking into account uncertainty, you get the SIA results.
What matters is not the total "evidence" you have access to but the time slices which, based on what you know, you might currently be.
>1. I don't get the problem. God has distinct thoughts about each haecceity. I don't think God is unique in this regard--a mind could easily have different thoughts about two qualitatively identical things.
"Having thoughts about two qualitatively identical things" is different from "having a way to refer to one specifically in the absence of any ostensive markers, such as proximity to the speaker." I can maybe think about a hypothetical universe with just two identical red spheres and nothing else, but I don't and can't have a name in my head that picks out one of the spheres individually - why would it pick out *that* sphere instead of the other one?
You can object and say: oh, but it's unproblematic to say, "imagine there are just two identical red spheres - say, one is A and the other is B..." My response is that I don't think "A" and "B" are really names there, even if they might grammatically function like ones in English; they're more like existentially quantified variables. By way of illustration, if we later encountered a red sphere out in the wild in real life, it would be absurd to ask if that sphere were really A and not B, or to ask under what conditions this would be so. And this remains true even if we grant that haecceities are real, because there's no reason to suspect that "A" would pick out one sphere's haecceity in the hypothetical universe rather than the other.
>2. God picks out the particular haecceities that he creates. On naturalism, to fully specify the world, you have to brutely build in the haecceities.
OK, but on your view the complete theory of the actual world involves God's choice to create this haecceity in this electron here, and that haecceity in that electron over there, and so forth, repeated ~10^80 times or whatever for each actually existing particle. How do we compress this description to something smaller - say, to fewer than ~10^80 characters?
>But you're not correct about what SIA implies if you take into account haecceities. The answer is exactly the same as if you ignore haecceities.
I'm not 100% sure what to say - I don't see how you've challenged what I said in my last comment rather than repeating that it's mistaken.
SIA in general says that, if E is your evidence, the posterior probability of A is the expected number of people who have E such that A is true for them, divided by the total expected number of people who have E. If you take into account haecceities and run this mathematical expression on your thought experiment, you'll see that the posterior of heads is 1/2.
If E is your sensory-evidence-with-haecceity of waking up and finding you're in the scenario (but not yet seeing your wall color), then in the heads world (which has prior 1/2), there's exactly 1 person with your haecceity-experience, because such haecceities are unique. And on the tails world (also prior 1/2), the same is true. So the total expected number of people with E is 1/2*1 + 1/2*1 = 1, and P(heads|E) = 1/2 * 1 / 1 = 1/2.
Whichever Elga-style reasoning by symmetry of self-locating evidence you're using to get an answer of P(heads|E) = 2/3, while it might be right, is incompatible with SIAH (= "SIA+haecceities"). SIAH is going to say that P(color_2&tails|E) is 1/4 and P(color_1&heads|E) = 1/2, so they're not equal.
I'm not going to respond to the non-SIA stuff but would be happy to discuss it over call.
You're making an error. It's true that P(my evidence)|tails=one if the coin came up tails and P(my evidence)|heads=one if the coin came up heads. But this doesn't rule out the inference I gave, wherein I'm uncertain about which kinds of evidence I have. It's the same error as is made with the inverse gambler's fallacy charge https://benthams.substack.com/p/the-multiverse-and-inverse-gamblers
All I can say is to just try plugging the scenario in to the expression for SIA I just mentioned! (Namely, if A is a statement and V is my observational evidence, then P(A|V) = E[#(A&V)]/E[#V], where "#blah" denotes the number of people for whom blah is true and E is expectation with respect to my priors.) The number for heads that pops out is 1/2, not 2/3, and this is all completely compatible with me being unsure about which haecceity my evidence has. And if you're not going by that mathematical expression or something equivalent to it, then you're not using SIA.
I think heacceities are not real apart from maybe minds. In your hypo about God switching two balls on either end of the universe, my intuition goes completely the other way. The operation you describe would change presicely nothing about the universe and is really a non-action. Sidereal-telos provides additional physical reasons to fund heasseitues implausible.
If haecceity only distinguishes an item from a duplicate it has elsewhere in spacetime or “meta-spacetime”, though, to me it isn’t clear what descriptive power it has that isn’t already provided by spacetime/meta-spacetime itself. If haecceity can only describe an item as far as it’s described by other categories, incorporating haecceities seems to make for a more rather than less complex model of the universe.
>It’s not obvious that God is the sort of thing that could have qualitative duplicates.
Yes it is, because you already have to restrict your omnipotence rules about him to account for free will and God not being willing to do any evil. If two or more omnipotent beings existed, we could easily modify the definition of omnipotence to preclude doing something metaphysically impossible, like overriding another omnipotent being's will. What's not obvious is why saying this would be metaphysically impossible would be more ad hoc than saying it would be metaphysically impossible for God to commit evil or violate your free will.
I'm not sure haecceities are a thing: or, at least, I'm not sure about many of your examples.
Take for instance the Castor and Pollux example. Castor and Pollux are meant to be identical, with no qualitative differences: but two items with no qualitative differences are not two items at all, they are the same item! Two red balls that are qualitatively identical with not only look the same, they will occupy the same location because location is a qualitative factor. Yet all the atoms of Castor cannot occupy the same location of all the atoms of Pollux: it would be like saying that there is a second you, but he is invisible to us because his atoms occupy the exact same locations as your atoms: in fact, there could be millions of copies of you, all occupying the same space. That doesn't seem right to me.
In the same way, I don't see how you could have two disembodied minds that are qualitatively identical: there must be something different between them, or else there isn't two minds but one. You might as well say that there could be millions of me all experiencing the exact same thing: I think there is only one, but there could be infinite other minds experiencing the exact same thing my mind experiences in the exact same way at the exact same time. I don't think that makes sense: a mind that is identical to me in every way, is just me.
Wouldn't all the irreducible haecceities of all the particles in the universe still remain under theism, just with the addition of God on top? If anything you could say that theism is less simple, because in addition to the haecceities of everything in physical reality, it posits an additional entity (God).
Well what matters to complexity is the fundamental facts (it isn't simple to believe in many planets because they're not fundamental--this is also why solipsism is implausible, even though it posits strictly less stuff than other theories). But the theists think only God is fundamental.
That could be right, but I worry that the view might run into problems depending on what it is to be "fundamental." If, for instance, being fundamental is a matter of having necessary existence, or being the creator of everything else, then it seems right (or at least plausible) that God would be the only fundamental being. But perhaps we could instead view being fundamental simply as being irreducible to some other type of entity. This latter understanding seems to be what's going on in many or most cases of charging a view with being unparsimonious. (E.g., if I come across someone who believes in both material objects and immaterial spirits, and I wish to make a parsimony-based objection to their view, I won't be thinking of the objection in terms of necessary existence or what creates what; I'll simply be thinking in terms of how their view countenances multiple radically different kinds of entities, kinds that can't be reduced to the other.) I worry, then, that there's a problem here for the haecceity-based argument for theism, given that on most theistic views, God and material objects are radically different kinds of entities (i.e., God is immaterial, and, although material objects are created by God, neither kind of entity can be reduced to the other). Some, at least, would argue that such a view indeed runs into a parsimony worry, and I'm not sure I see how some variant of "but only God is fundamental" addresses the worry.
Thanks, that helps me understand the argument a bit better. I still wonder whether there might be a parsimony worry lurking here, though. Suppose, for instance, that we had a view according to which there are both material objects and immaterial spirits, magic, etc., but that every magical/spiritual entity was explained by some physical entity. Perhaps, for instance, there's a particular particle that's very special, and, depending on where it is in relation to other particles at a given time, what it's doing at a given moment, etc., new magical and spiritual entities are being created all the time by its activities. (Maybe it's simply a law of this possible world, for instance, that any time this special particle bumps into a negatively charged particle, a ghost is created somewhere.) Now, certainly there'd be room for a lot of objections to this view, but here I want to focus on parsimony. At least to me, it seems intuitive that such a view, in positing both material objects and magical/spiritual entities (the latter of which, while created or explained by the former, couldn't be reduced to the former), would be unparsimonious. If a defender of the view replied that it's not an unparsimonious view since the magical/spiritual entities are not fundamental, I can't help feeling that this would simply be missing the force of the objection.
Couldn't the fundamental facts be something impersonal like "the quantum foam" rather than a personal God? If we're positing fundamental entities to be more likely based on their simplicity, maybe we might posit an entity of absolute goodness, but it seems more complex to posit that this entity intervenes in reality to save each and every one of our souls. So in regards to simplicity, it seems most likely to posit an impersonal ultimate entity that everything else is derived from, and if it's impersonal and doesn't interfere to rescue our souls and put them in some sort of afterlife, which is a course of action that seems less than absolutely simple, then there seems to be no point in calling this ultimate entity "God," even if it has absolute perfection.
And God wouldn't? I'm afraid I might be misunderstanding something here, because it seems like even with God the problem of instantiating every haecceity would remain.
Seems like if the people on the two planets are identical in every respect, then destroying one of them changes nothing. Every experience that would happen will still happen. Nothing’s been lost.
Also, again. Endless a priori arguments for God are bad. Until you manage to become an angel, reality is what you gotta consider.
Declaring these worlds possible doesn't make them possible equivalent to the world we know. Your declaration of "possible" is doing a lot of work. Call it philosophical fiction as a genre.
Leaving aside questions of personal identity for a moment, quantum mechanics seems to very clearly exclude a notion of persistent identity for particles.
First, in the simple case where the amount and type of particles doesn't change, we can set up experiments where two multi-particle states are arrived at with opposite phase, and see if they interfere with each other. When the states differ only in the identity of the particles, we see that they do, so for example, "electron A in position X, electron B in position Y" can destructively interfere with "electron B in position X, electron A in position Y". Or it can interfere constructively, in which case each assignment of labels is equally valid.
Secondly, in the more fundamental theory of quantum fields, individual particles are just waves in those fields. Individual waves can have a meaningful kind of identity, if they don't interact too much with other waves, but in the general case waves can be created, destroyed, combine or split apart, or enter complicated interactions where you can't really pick out any waves any more at all, let alone identify "which" input wave they "really are". The situation in the simpler case arises because states are not distinguished by how they arose, only by the field value at each point, so "swapping" two identical particles is just the same state you started with.
This notion of fundamental identities also has a serious epistemological issue: if these identities don't effect any feature of the physical world, how could you possibly have learned of them? For example, you probably have an intuition that normally identities are persistent over time, but this intuition was not caused by you observing any physical event that demonstrates persistent identity because identity doesn't cause any physical events. So you would retain it even if, in truth, the identity of all trees on Earth were actually being shuffled every 6 hours, unless perhaps you also hold that God intervened to give you correct intuitions.
I think this sense that things have identities that persist over time independently of their physical state is just a cognitive shortcut humans use, which is approximately valid in our ordinary experience, but has no fundamental reality. Our experience involves lots of physically contiguous objects that don't change much over time, and don't often merge with, or split from, other objects of interest, and two previously distinct objects are almost never rendered physically identical in every way, so it's useful to think of objects as having a unique identity and associated history, but if you leave the ordinary experience this can quickly break down.
I don't really understand the physics, but even if particles don't actually persist over time, it's at least conceivable that they could. This means there are irreducible haecceities, which is all you need to get the argument off the ground (well, plus the other stuff).
I think that we are capable of intuiting true things even if the things we intuit don't explain features of our experience--e.g. moral facts.
I think it's a serious error to encounter a place where reality directly contradicts an intuition and insist that the intuition is still metaphysically correct because you can imagine it being true. Some things you can conceive of are just false, incoherent, logically contradictory, or metaphysically invalid, and looking at how the world actually works is one of the few ways to discover that.
Out of curiosity, where do you fall on A vs B theory of time? That's the other case I'm aware of, where physics gave a direct, and very counterintuitive, statement on a philosophical issue. Do you think our conscious experience of existing at a specific moment in time proves there is an objective present?
Can you explain what you're doing when you're conceiving 0 dimensional particles with no inner structure, size, or shape, but positive mass? What exactly is conceivable about Newtonian particles? Or are you conceiving something else by "particle?"
Correct, BB frequently makes declarations about science explaining the fundamental nature of reality, but has no clue about what the methodologies or findings of e.g. quantum physics are. He then makes an appeal from his intution about how widespread e.g. identity statements are and bakes in his presuppositions about how other fields of science use e.g. identity heuristics, and falsly claims that since his theory makes use of the same identity concept as scientific fields, his arguments gain extra epistemic virtue points.
I definitely don't think that, whatever your theory of complexity/simplicity is, hypotheses should be penalized for failing to specify haecceities, as opposed to just positing the existence of objects which bear certain relations between them but are otherwise "anonymous." I don't exactly even know what it would mean to specify a haecceity, other than to point ostensively to things around you and being like "that specific thing over there." And I don't think anyone grades the simplicity of a theory of physics based on pointing to anything, as opposed to its abstract mathematical character which would be the same even if you woke up in a black room with no memories and couldn't point to anything at all.
And I still don't really see how God is helping you here. First because it's not clear how God decides to create this electron instead of a different, indistinguishable electron, and second because your theory of what God does is going to have to build in all of his countless decisions to build this and that haecceity-specific electron in exactly the same way you accuse the atheist of needing to do. So the complex-due-to-haecceity theory of physics has been derived from something else, yes, but it's an equally complex theory of divine action.
I think most of your examples motivating haecceitism seem like they'd be easy to bite the bullet on for an anti-haecceitist - indeed, they are precisely sort of the paradigmatic cases meant to illustrate to novices what anti-haecceitism even means! It actually seems sort of common in metaphysics in general to argue that the existence of a symmetry implies the illusoriness of some intuitive metaphysical thing. For instance, a lot of people would be motivated to say that God couldn't have created the whole universe shifted five meters to the left of where it actually is (perhaps we need to pretend we live in a Newtonian universe for this to make sense, IDK), because what would be the real difference?
Finally, I've privately wondered if haecceity-centric viewpoints undercut SIA, or at least lead it to drastically different conclusions than it's usually taken to lead to. For example, in any of the standard red-vs.-blue jacket thought experiments, we're called to ask what the probability is of God's coin landing heads conditional on our observing ourselves having a red jacket - SIA says the answer is going to be based on the expected number of people who have such observations depending on coin outcomes. But if we instead ask what the probability is of God flipping heads conditional on ourselves observing *this specific* experience of a red jacket, then there's never going to be more than one of those in any world, no matter how many qualitatively identical observers there are. In other words, if SIA is based on computing the number of possible people who have my evidence, then no more than one person truly has *my* evidence in this sense.
1. To specify a haecceity, presumably you'd need a symbol of some sort attached to every haecceity to pick it out specifically, the same way I think you'd need for mental states.
2. The reason to think that we need to pick out the haecceities specifically is the same as the reason needed to pick out other facts.
3. God can pick which electrons he creates because he has a vivid mental grasp of every haecceity and picks which electron to make.
4. I think that God's decisions will follow from something deeper. You definitely don't want to just brutely build in all his decisions.
5. I have very different intuitions, especially about 3.
6. I don't think the point about SIA is right, because SIA gets off the ground if you just are uncertain about which of the haecceistic people you are--see Elga's proof https://benthams.substack.com/p/elga-proved-13
>1. To specify a haecceity, presumably you'd need a symbol of some sort attached to every haecceity to pick it out specifically, the same way I think you'd need for mental states.
This is saying God has a special mental symbol in his head that picks out a haecceity, for each such haecceity. OK, but how does he manage to do that? What sort of thing pops up in his mind so that symbol X ends up picking out electron haecceity A instead of qualitatively identical electron haecceity B? He's not merely imagining the electron's location, shape, charge, spin, or whatever, since none of these pick out the haecceity - so what's going on?
As usual with questions about "how does God do anything," I imagine the answer is just going to be posit that it's some sort of fundamental primitive. This is, to me, unsatisfying. And in this case, I don't even think I understand what's being suggested - I don't know what it means to have a direct mental representation of a particular haecceity, independent of having some way of referring to it ostensively. That is, *maybe* I can accept talk about my chair's haecceity in terms of "the haecceity of the thing that's impressing upon me such-and-such sensory perceptions," but if I counterfactually didn't have any those sensory perceptions, it feels nonsensical to imagine that I could think of my (actual) chair specifically. And this has nothing to do with needing an infinite number of representational symbols in my head - I don't think I have even one symbol that's like this, nor can I easily imagine what having such a symbol would be like subjectively.
>2. The reason to think that we need to pick out the haecceities specifically is the same as the reason needed to pick out other facts.
The problem is that I don't see in principle what a more or less simple explanation of haecceities is supposed to look like, on any theory, so it doesn't really make sense to take it into consideration here. How does theism predict that God wanted my hand to contain this specific electron instead of a qualitatively identical electron, without simply building that statement in as an additional posit? I know you suggest that you think there's some way to derive this from something simpler than merely building it in, but I'm having trouble seeing how this is supposed to work.
>6. I don't think the point about SIA is right, because SIA gets off the ground if you just are uncertain about which of the haecceistic people you are--see Elga's proof https://benthams.substack.com/p/elga-proved-13
I'm not saying this vitiates SIA per se, just that it drastically changes the answers that SIA outputs, essentially trivializing it so that the priors never change in response to anthropic reasoning. It's true that I can be uncertain about which person's experiences have the same haecceities as my own, but the number of possible people in any epistemically possible world whose experiences have this property is always exactly 1, and "the expected number of possible people in a world who have my evidence" is exactly what mediates updates in SIA.
So, for example, in the Sleeping Beauty case you refer me to here, haecceitistic SIA should recommend halving. If the coin landed heads, the expected number of observers across time who have *this* precise experience of waking up (as opposed to merely some similar experience of waking up) is 1. If the coin landed tails, the same thing is true. So, since the coin was fair, the posterior should also remain 1/2, and you should reject Elga's original thirder reasoning on the basis of SIA.
(You can get around all this by just building into SIA that you should ignore haecceities, but that seems to be the flavor of thing your post rejects.)
1. I don't get the problem. God has distinct thoughts about each haecceity. I don't think God is unique in this regard--a mind could easily have different thoughts about two qualitatively identical things.
2. God picks out the particular haecceities that he creates. On naturalism, to fully specify the world, you have to brutely build in the haecceities.
6. Well I think there would be nothing wrong with having SIA involve ignoring haecceities as, while real, they're not part of their evidence.
But you're not correct about what SIA implies if you take into account haecceities. The answer is exactly the same as if you ignore haecceities.
Analogy: a fair coin is flipped. If it comes up heads I'll wake up in a room with a particular shade of red wall. If it comes up tails, I'll wake up in that room, and then again in a room with a slightly different red wall shade. On SIA, after waking up and seeing a wall color of some sort, you should think that tails is twice as likely as heads because:
p(wall color 1)&heads=p(wall color 1)&tails=p(wall color 2)&tails.
Same basic idea applies to other SIA cases with haecceities. In this case, like the haecceities case, your evidence may be very specific, but it's specific in a way that you don't know about, so taking into account uncertainty, you get the SIA results.
What matters is not the total "evidence" you have access to but the time slices which, based on what you know, you might currently be.
>1. I don't get the problem. God has distinct thoughts about each haecceity. I don't think God is unique in this regard--a mind could easily have different thoughts about two qualitatively identical things.
"Having thoughts about two qualitatively identical things" is different from "having a way to refer to one specifically in the absence of any ostensive markers, such as proximity to the speaker." I can maybe think about a hypothetical universe with just two identical red spheres and nothing else, but I don't and can't have a name in my head that picks out one of the spheres individually - why would it pick out *that* sphere instead of the other one?
You can object and say: oh, but it's unproblematic to say, "imagine there are just two identical red spheres - say, one is A and the other is B..." My response is that I don't think "A" and "B" are really names there, even if they might grammatically function like ones in English; they're more like existentially quantified variables. By way of illustration, if we later encountered a red sphere out in the wild in real life, it would be absurd to ask if that sphere were really A and not B, or to ask under what conditions this would be so. And this remains true even if we grant that haecceities are real, because there's no reason to suspect that "A" would pick out one sphere's haecceity in the hypothetical universe rather than the other.
>2. God picks out the particular haecceities that he creates. On naturalism, to fully specify the world, you have to brutely build in the haecceities.
OK, but on your view the complete theory of the actual world involves God's choice to create this haecceity in this electron here, and that haecceity in that electron over there, and so forth, repeated ~10^80 times or whatever for each actually existing particle. How do we compress this description to something smaller - say, to fewer than ~10^80 characters?
>But you're not correct about what SIA implies if you take into account haecceities. The answer is exactly the same as if you ignore haecceities.
I'm not 100% sure what to say - I don't see how you've challenged what I said in my last comment rather than repeating that it's mistaken.
SIA in general says that, if E is your evidence, the posterior probability of A is the expected number of people who have E such that A is true for them, divided by the total expected number of people who have E. If you take into account haecceities and run this mathematical expression on your thought experiment, you'll see that the posterior of heads is 1/2.
If E is your sensory-evidence-with-haecceity of waking up and finding you're in the scenario (but not yet seeing your wall color), then in the heads world (which has prior 1/2), there's exactly 1 person with your haecceity-experience, because such haecceities are unique. And on the tails world (also prior 1/2), the same is true. So the total expected number of people with E is 1/2*1 + 1/2*1 = 1, and P(heads|E) = 1/2 * 1 / 1 = 1/2.
Whichever Elga-style reasoning by symmetry of self-locating evidence you're using to get an answer of P(heads|E) = 2/3, while it might be right, is incompatible with SIAH (= "SIA+haecceities"). SIAH is going to say that P(color_2&tails|E) is 1/4 and P(color_1&heads|E) = 1/2, so they're not equal.
I'm not going to respond to the non-SIA stuff but would be happy to discuss it over call.
You're making an error. It's true that P(my evidence)|tails=one if the coin came up tails and P(my evidence)|heads=one if the coin came up heads. But this doesn't rule out the inference I gave, wherein I'm uncertain about which kinds of evidence I have. It's the same error as is made with the inverse gambler's fallacy charge https://benthams.substack.com/p/the-multiverse-and-inverse-gamblers
All I can say is to just try plugging the scenario in to the expression for SIA I just mentioned! (Namely, if A is a statement and V is my observational evidence, then P(A|V) = E[#(A&V)]/E[#V], where "#blah" denotes the number of people for whom blah is true and E is expectation with respect to my priors.) The number for heads that pops out is 1/2, not 2/3, and this is all completely compatible with me being unsure about which haecceity my evidence has. And if you're not going by that mathematical expression or something equivalent to it, then you're not using SIA.
I think heacceities are not real apart from maybe minds. In your hypo about God switching two balls on either end of the universe, my intuition goes completely the other way. The operation you describe would change presicely nothing about the universe and is really a non-action. Sidereal-telos provides additional physical reasons to fund heasseitues implausible.
Yet another confusion that immediately dissolves as soon as you understand map-territory relations.
This-ness is not a property of an object, it's a property of a mind that is thinking about an object mentally labeling it as "this".
For the record, this arrived in my email half hour before you.
https://www.spanishdict.com/translate/hechizar?e_en=wotd&e_co=wotd&e_ce=word&e_d=2024-10-13
If haecceity only distinguishes an item from a duplicate it has elsewhere in spacetime or “meta-spacetime”, though, to me it isn’t clear what descriptive power it has that isn’t already provided by spacetime/meta-spacetime itself. If haecceity can only describe an item as far as it’s described by other categories, incorporating haecceities seems to make for a more rather than less complex model of the universe.
>It’s not obvious that God is the sort of thing that could have qualitative duplicates.
Yes it is, because you already have to restrict your omnipotence rules about him to account for free will and God not being willing to do any evil. If two or more omnipotent beings existed, we could easily modify the definition of omnipotence to preclude doing something metaphysically impossible, like overriding another omnipotent being's will. What's not obvious is why saying this would be metaphysically impossible would be more ad hoc than saying it would be metaphysically impossible for God to commit evil or violate your free will.
I'm not sure haecceities are a thing: or, at least, I'm not sure about many of your examples.
Take for instance the Castor and Pollux example. Castor and Pollux are meant to be identical, with no qualitative differences: but two items with no qualitative differences are not two items at all, they are the same item! Two red balls that are qualitatively identical with not only look the same, they will occupy the same location because location is a qualitative factor. Yet all the atoms of Castor cannot occupy the same location of all the atoms of Pollux: it would be like saying that there is a second you, but he is invisible to us because his atoms occupy the exact same locations as your atoms: in fact, there could be millions of copies of you, all occupying the same space. That doesn't seem right to me.
In the same way, I don't see how you could have two disembodied minds that are qualitatively identical: there must be something different between them, or else there isn't two minds but one. You might as well say that there could be millions of me all experiencing the exact same thing: I think there is only one, but there could be infinite other minds experiencing the exact same thing my mind experiences in the exact same way at the exact same time. I don't think that makes sense: a mind that is identical to me in every way, is just me.
Wouldn't all the irreducible haecceities of all the particles in the universe still remain under theism, just with the addition of God on top? If anything you could say that theism is less simple, because in addition to the haecceities of everything in physical reality, it posits an additional entity (God).
Well what matters to complexity is the fundamental facts (it isn't simple to believe in many planets because they're not fundamental--this is also why solipsism is implausible, even though it posits strictly less stuff than other theories). But the theists think only God is fundamental.
That could be right, but I worry that the view might run into problems depending on what it is to be "fundamental." If, for instance, being fundamental is a matter of having necessary existence, or being the creator of everything else, then it seems right (or at least plausible) that God would be the only fundamental being. But perhaps we could instead view being fundamental simply as being irreducible to some other type of entity. This latter understanding seems to be what's going on in many or most cases of charging a view with being unparsimonious. (E.g., if I come across someone who believes in both material objects and immaterial spirits, and I wish to make a parsimony-based objection to their view, I won't be thinking of the objection in terms of necessary existence or what creates what; I'll simply be thinking in terms of how their view countenances multiple radically different kinds of entities, kinds that can't be reduced to the other.) I worry, then, that there's a problem here for the haecceity-based argument for theism, given that on most theistic views, God and material objects are radically different kinds of entities (i.e., God is immaterial, and, although material objects are created by God, neither kind of entity can be reduced to the other). Some, at least, would argue that such a view indeed runs into a parsimony worry, and I'm not sure I see how some variant of "but only God is fundamental" addresses the worry.
I fundamental entity is one that isn't explained by further entities. But God explains why there's a physical world--he wills it.
Thanks, that helps me understand the argument a bit better. I still wonder whether there might be a parsimony worry lurking here, though. Suppose, for instance, that we had a view according to which there are both material objects and immaterial spirits, magic, etc., but that every magical/spiritual entity was explained by some physical entity. Perhaps, for instance, there's a particular particle that's very special, and, depending on where it is in relation to other particles at a given time, what it's doing at a given moment, etc., new magical and spiritual entities are being created all the time by its activities. (Maybe it's simply a law of this possible world, for instance, that any time this special particle bumps into a negatively charged particle, a ghost is created somewhere.) Now, certainly there'd be room for a lot of objections to this view, but here I want to focus on parsimony. At least to me, it seems intuitive that such a view, in positing both material objects and magical/spiritual entities (the latter of which, while created or explained by the former, couldn't be reduced to the former), would be unparsimonious. If a defender of the view replied that it's not an unparsimonious view since the magical/spiritual entities are not fundamental, I can't help feeling that this would simply be missing the force of the objection.
Couldn't the fundamental facts be something impersonal like "the quantum foam" rather than a personal God? If we're positing fundamental entities to be more likely based on their simplicity, maybe we might posit an entity of absolute goodness, but it seems more complex to posit that this entity intervenes in reality to save each and every one of our souls. So in regards to simplicity, it seems most likely to posit an impersonal ultimate entity that everything else is derived from, and if it's impersonal and doesn't interfere to rescue our souls and put them in some sort of afterlife, which is a course of action that seems less than absolutely simple, then there seems to be no point in calling this ultimate entity "God," even if it has absolute perfection.
But the foam would need to be fundamental and have haecceities and to pick out higher order entities with haecceities.
And God wouldn't? I'm afraid I might be misunderstanding something here, because it seems like even with God the problem of instantiating every haecceity would remain.
God can pick which haecceity to instantiate.
Seems like if the people on the two planets are identical in every respect, then destroying one of them changes nothing. Every experience that would happen will still happen. Nothing’s been lost.
Also, again. Endless a priori arguments for God are bad. Until you manage to become an angel, reality is what you gotta consider.
Sounds plausible!
But does the argument assume that on theism God is the only fundamental entity?
If so, it seems theism is much simpler than atheism even without haecceitism
Declaring these worlds possible doesn't make them possible equivalent to the world we know. Your declaration of "possible" is doing a lot of work. Call it philosophical fiction as a genre.