I think (i) your reasoning is flawed, though—even if barely anyone will be agreeing to it - (ii) actually have some belief in something related to what you say
(i) YOUR BAYESIAN REASONING IS FLAWED:
As Yair points out, one can easily take a different conclusion from your starting point, and maybe it’s best to stop there. Here still an attempt of a Bayesian tracking why; it’s all a bit trivial, but maybe its worth could be: if you really believe in the conclusions brought in OP, maybe you can take it as a starting point and pinpoint where exactly you’d argue a Bayesian implementation of the reflection ought to look differently.
Assume we have, in line with your setup, two potential states of the world—without going into detail as to what these terms would even mean:
A = Unified Consciousness B = Separate Consciousness for each individual
The world is, of course, exactly the same in both cases, except for this underlying feature. So any Joe born in location xyz at date abc will be that exact same Joe born then and there under either of the hypothetical A and B, except for the underlying nature of his consciosusness to differ in the sense of A vs. B.
We know there are
9 gazillion potential humans (your atoms or sperms or whatever) that could theoretically be brought into existence
9 bn actual humans, materializing out of these 9 gazillion potential ones
Potential and actual numbers are the same in world case A and world case B, just their consciousness(es) is/are somehow of a different nature.
Now, consider in both hypothetical worlds a random existing human # 7029501952, born to the name of Joe, among the 9 bn existing ones. Joe can indeed ask himself: “Given that I exist—wow, I exist! - how likely is that there is a unified vs. separate… He does the Bayesian update given his evidence at hand. From his perspective
P(A | Joe exist) = P(Joe exist | A) x P(A)/P(Joe exist) P(B | Joe exist) = P(Joe exist | B) x P(B)/P(Joe exist)
As we’re in a bit a weird thought experiment, you may argue to have only one or two of the following possibilities to evaluate this ( think the first makes more sense as we’re talking about his perspective, but if you happen to prefer seeing it the other way round; won’t change anything):
P(Joe exist) = 100%, after all in his world definitely he exists, and in this case also P(Joe exist | A) = 100% (and P(Joe exist | B) = 100% too): the two worlds are the same except for the underlying consciousness nuance; A & B do not differ about THAT PERSON Joe existing per se, but only about the nature/existence of links between consciousnesses
P(Joe exist) = 1bn/1 gazillion = mu << 1, after all, from a more abstract perspective, it was unlikely for Joe t become! In this case, of course, person Joe has P(Joe exist | A) = mu as well (and P(Joe exist | B) = mu as well): again, which rare few humans come into being among the gazillion possible ones, is not dependent on the two potential worlds, it is only whether it’s a unified consciousness or not, that’s a different point.
If you substitute that in you get one of
P(A | Joe exist) = 100% x 0.5/100% = 0.5
P(A | Joe exist) = mu x 0.5/mu = 0.5
And the same 0.5 in both cases for P(B | Joe exists).
So, the probability of A and of B remains at 0.5 just as it initially was.
In simplified words—just like the maths also they feel a bit trivial: Given by definition only the existing humans—no matter whether their atomic consciousnesses or somehow one single connected one—exist, and can thus ask themselves about their existence, the fact that they exist despite the many hypothetical humans individually only rarely becoming actual existences, doesn’t reduce the probability of them having been born into a world of type B as opposed to type A. I.e., whatever our prior for world A vs. world B, your type of reasoning does not actually yield any changed posterior.
(ii) I THINK UNIFIED CONSCIOUSNESS—IN SOME SENSE—MAKES SORT OF SENSE
FWIW I’m half convinced we can sort of know we’re more ‘one’ than ‘separate’ as it follows from a observation insight and thought experiment: (a) there’s not much more in “us” at any given moment than an instantaneous self and memories and intentions/preferences regarding a future self that happens to be in the same ‘body’, but (b) it suffices any random selection of a large set of thought experiments about sleeping/cloning/awaking that can show we can very happily imagine ourselves to ‘be’ an entire different future in the next moment in a way that imho can best be made sense of if there is not really just a stable and well-defined long-term self but instead (either no such thing as any self in any meaningful way, i.e. something a bit illusionist or) a wholly flimsy/random continuation of self, in a way that may well best be described as there being a single self or something (and half esoterically I derive from it I should really better care about everyone’s welfare equally well as opposed to mainly about the one of my own physical longer-term being, though it’s all fuzzy), as I try to explain in Relativity Theory for What the Future ‘You’ Is and Isn’t.
I appreciate your detailed reply. Let me begin with a small clarification. I would say Universalism is better conceived of as there being simply a universal property (the immediacy of experience) that defines me, rather than any kind of “unified consciousness.”
I think that your original calculation failed to deliver a result, because it began with the assumption that human #7029501952 (Joe) already existed. Then of course, when Joe asks himself, what is the probability that I, human #7029501952 exist, this cannot count as evidence favoring either hypothesis.
It is equivalent to altering the Awakening Game above, where the pattern of coin flips is a priori stipulated to be the specific pattern matching the sleeper, which of course would not help the awakener decide which game was played.
Given that, let me explain how I see the Bayesian reasoning apply to deciding between these two hypotheses in personal identity:
A—Universalism (I exist in every conscious perspective, regardless of conditions/configurations) B—The Usual View (I exist only because an absolutely specific pattern of begettings occurred) O—The observation that “I exist”
Again let’s set both priors to 0.5.
P(A) = 0.5 P(B) = 0.5
And P(O) = 1 (the starting basis of our assumption, I exist, or I have awakened)
Note that the difference between A and B is that B requires a specific pattern of antecedent begettings, or else, “I would not exist”, “I would never have been born”, etc. If we go back to consider just 3 human begettings each of which requires winning a “sperm cell lottery” having odds of 1 in 200,000,000, then those 3 begettings have a probability of 1 in 8 septillion.
Let’s call this probability of winning the ancestral sperm cell lottery: P(O | B) = (1/200,000,000)^3 = 1.25 × 10^-25 = 0.0000000000000000000000125%
But note that the above improbability only applies to the Usual View, for only the Usual View introduced the assumption that being born required a specific pattern of begettings. But one doesn’t have to win any lotteries in the case of universalism, so: P(O | A) = 100%.
Now let us update our priors given the evidence/observation “I exist” (O):
Note that the sharp reduction in probability for P(B | O) is entirely due to B’s additional constraint that stipulates your existence on the existence a very particular being, brought about by a very particular set of circumstances. Universalism doesn’t do this, and so survives the improbability of the sperm cell lotteries unscathed.
Now as to what you say in part (ii) of your reply, I agree. I think thought experiments involving duplication, cloning, teletransporters, etc. show that “being me” is not a matter of inheriting any particular physical body. And likewise, thought experiments involving partial or total amnesia, memory implantation, psychological changes induced by brain injury, drugs, or aging, etc. undermine the notion that bundles of memories or personality traits are what “makes me me.” Universalism then, is the natural conclusion that follows from abandoning both bodily, and psychological continuity theories when it comes to personal identity. But then, what is left that makes an experience mine? As Zuboff writes on page 26: https://www.pdcnet.org/wp/wp-content/uploads/2025/12/Zuboff_MSP-Supplement_2025.pdf
“It would be a very weird view that something as obviously incidental as wearing a blue shirt was essential to my existence as an individual subject of experience. Nobody would think that my putting on a different coloured shirt would replace me with someone else whose experience and self-interest would no longer be mine. The usual view is that something far more substantive-seeming, like the identity of my body (or soul) or the continuing of my memories (which might in some strange hypothetical case be redirected into a different body or soul) is what is essentially involved in my continuing existence as a particular centre of experience and self-interest. Replace the body (or soul) or replace the mental continuity by a different mental stream and then I’d no longer be there but rather someone else. Universalism says that what’s essential is just the much more general property of the experience being immediate—the experience being had in first-person style. As we’ve seen in answering the riddle of finding myself, the experience being immediate, being fist-person in style, is the only way I identify which being I am; and, as I am also saying, that is all that’s really involved in making something be me.”
Given what you write in “Relativity Theory for What the Future ‘You’ Is and Isn’t.” I think you would much enjoy the rest of Zuboff’s book.
Thanks, the suggestion sounds interesting. However; first quick update fwiw: I’ve only had the chance to read the first small section, “A Brief Proof at You Are Every Conscious Thing”, and I must say to me it seems totally clear he’s essentially making the same Bayesian mistake—or sort of Anthropic reasoning mistake—that OP contains. It’s totally not making sense the way he puts it, and I’m slightly surprised he published it like that.
I plan to read more and to provide my view on the rest of his argument—hopefully I’ll not fail despite time pressure.
I think (i) your reasoning is flawed, though—even if barely anyone will be agreeing to it - (ii) actually have some belief in something related to what you say
(i) YOUR BAYESIAN REASONING IS FLAWED:
As Yair points out, one can easily take a different conclusion from your starting point, and maybe it’s best to stop there. Here still an attempt of a Bayesian tracking why; it’s all a bit trivial, but maybe its worth could be: if you really believe in the conclusions brought in OP, maybe you can take it as a starting point and pinpoint where exactly you’d argue a Bayesian implementation of the reflection ought to look differently.
Assume we have, in line with your setup, two potential states of the world—without going into detail as to what these terms would even mean:
A = Unified Consciousness
B = Separate Consciousness for each individual
The world is, of course, exactly the same in both cases, except for this underlying feature. So any Joe born in location xyz at date abc will be that exact same Joe born then and there under either of the hypothetical A and B, except for the underlying nature of his consciosusness to differ in the sense of A vs. B.
We know there are
9 gazillion potential humans (your atoms or sperms or whatever) that could theoretically be brought into existence
9 bn actual humans, materializing out of these 9 gazillion potential ones
Potential and actual numbers are the same in world case A and world case B, just their consciousness(es) is/are somehow of a different nature.
Let’s start with an even prior:
P(Unified Consciousness) = P(Separated Consciousnesses) = 0.5
Now, consider in both hypothetical worlds a random existing human # 7029501952, born to the name of Joe, among the 9 bn existing ones. Joe can indeed ask himself: “Given that I exist—wow, I exist! - how likely is that there is a unified vs. separate… He does the Bayesian update given his evidence at hand. From his perspective
P(A | Joe exist) = P(Joe exist | A) x P(A)/P(Joe exist)
P(B | Joe exist) = P(Joe exist | B) x P(B)/P(Joe exist)
As we’re in a bit a weird thought experiment, you may argue to have only one or two of the following possibilities to evaluate this ( think the first makes more sense as we’re talking about his perspective, but if you happen to prefer seeing it the other way round; won’t change anything):
P(Joe exist) = 100%, after all in his world definitely he exists, and in this case also P(Joe exist | A) = 100% (and P(Joe exist | B) = 100% too): the two worlds are the same except for the underlying consciousness nuance; A & B do not differ about THAT PERSON Joe existing per se, but only about the nature/existence of links between consciousnesses
P(Joe exist) = 1bn/1 gazillion = mu << 1, after all, from a more abstract perspective, it was unlikely for Joe t become! In this case, of course, person Joe has P(Joe exist | A) = mu as well (and P(Joe exist | B) = mu as well): again, which rare few humans come into being among the gazillion possible ones, is not dependent on the two potential worlds, it is only whether it’s a unified consciousness or not, that’s a different point.
If you substitute that in you get one of
P(A | Joe exist) = 100% x 0.5/100% = 0.5
P(A | Joe exist) = mu x 0.5/mu = 0.5
And the same 0.5 in both cases for P(B | Joe exists).
So, the probability of A and of B remains at 0.5 just as it initially was.
In simplified words—just like the maths also they feel a bit trivial: Given by definition only the existing humans—no matter whether their atomic consciousnesses or somehow one single connected one—exist, and can thus ask themselves about their existence, the fact that they exist despite the many hypothetical humans individually only rarely becoming actual existences, doesn’t reduce the probability of them having been born into a world of type B as opposed to type A. I.e., whatever our prior for world A vs. world B, your type of reasoning does not actually yield any changed posterior.
(ii) I THINK UNIFIED CONSCIOUSNESS—IN SOME SENSE—MAKES SORT OF SENSE
FWIW I’m half convinced we can sort of know we’re more ‘one’ than ‘separate’ as it follows from a observation insight and thought experiment: (a) there’s not much more in “us” at any given moment than an instantaneous self and memories and intentions/preferences regarding a future self that happens to be in the same ‘body’, but (b) it suffices any random selection of a large set of thought experiments about sleeping/cloning/awaking that can show we can very happily imagine ourselves to ‘be’ an entire different future in the next moment in a way that imho can best be made sense of if there is not really just a stable and well-defined long-term self but instead (either no such thing as any self in any meaningful way, i.e. something a bit illusionist or) a wholly flimsy/random continuation of self, in a way that may well best be described as there being a single self or something (and half esoterically I derive from it I should really better care about everyone’s welfare equally well as opposed to mainly about the one of my own physical longer-term being, though it’s all fuzzy), as I try to explain in Relativity Theory for What the Future ‘You’ Is and Isn’t.
Hi FlorianH,
I appreciate your detailed reply. Let me begin with a small clarification. I would say Universalism is better conceived of as there being simply a universal property (the immediacy of experience) that defines me, rather than any kind of “unified consciousness.”
I think that your original calculation failed to deliver a result, because it began with the assumption that human #7029501952 (Joe) already existed. Then of course, when Joe asks himself, what is the probability that I, human #7029501952 exist, this cannot count as evidence favoring either hypothesis.
It is equivalent to altering the Awakening Game above, where the pattern of coin flips is a priori stipulated to be the specific pattern matching the sleeper, which of course would not help the awakener decide which game was played.
Given that, let me explain how I see the Bayesian reasoning apply to deciding between these two hypotheses in personal identity:
A—Universalism (I exist in every conscious perspective, regardless of conditions/configurations)
B—The Usual View (I exist only because an absolutely specific pattern of begettings occurred)
O—The observation that “I exist”
Again let’s set both priors to 0.5.
P(A) = 0.5
P(B) = 0.5
And P(O) = 1 (the starting basis of our assumption, I exist, or I have awakened)
Note that the difference between A and B is that B requires a specific pattern of antecedent begettings, or else, “I would not exist”, “I would never have been born”, etc. If we go back to consider just 3 human begettings each of which requires winning a “sperm cell lottery” having odds of 1 in 200,000,000, then those 3 begettings have a probability of 1 in 8 septillion.
Let’s call this probability of winning the ancestral sperm cell lottery:
P(O | B) = (1/200,000,000)^3 = 1.25 × 10^-25 = 0.0000000000000000000000125%
But note that the above improbability only applies to the Usual View, for only the Usual View introduced the assumption that being born required a specific pattern of begettings. But one doesn’t have to win any lotteries in the case of universalism, so:
P(O | A) = 100%.
Now let us update our priors given the evidence/observation “I exist” (O):
P(A | O) = (P(O | A) × P(A)) / P(O) = (1 × 0.5) / 1 = 0.5
P(B | O) = (P(O | B) × P(B)) / P(O) = (0.0000000000000000000000125% × 0.5 / 1 = 6.25 × 10^-26
Note that the sharp reduction in probability for P(B | O) is entirely due to B’s additional constraint that stipulates your existence on the existence a very particular being, brought about by a very particular set of circumstances. Universalism doesn’t do this, and so survives the improbability of the sperm cell lotteries unscathed.
Now as to what you say in part (ii) of your reply, I agree. I think thought experiments involving duplication, cloning, teletransporters, etc. show that “being me” is not a matter of inheriting any particular physical body. And likewise, thought experiments involving partial or total amnesia, memory implantation, psychological changes induced by brain injury, drugs, or aging, etc. undermine the notion that bundles of memories or personality traits are what “makes me me.” Universalism then, is the natural conclusion that follows from abandoning both bodily, and psychological continuity theories when it comes to personal identity. But then, what is left that makes an experience mine? As Zuboff writes on page 26: https://www.pdcnet.org/wp/wp-content/uploads/2025/12/Zuboff_MSP-Supplement_2025.pdf
“It would be a very weird view that something as obviously incidental as wearing a blue shirt was essential to my existence as an individual subject of experience. Nobody would think that my putting on a different coloured shirt would replace me with someone else whose experience and self-interest would no longer be mine.
The usual view is that something far more substantive-seeming, like the identity of my body (or soul) or the continuing of my memories (which might in some strange hypothetical case be redirected into a different body or soul) is what is essentially involved in my continuing existence as a particular centre of experience and self-interest. Replace the body (or soul) or replace the mental continuity by a different mental stream and then I’d no longer be there but rather someone else.
Universalism says that what’s essential is just the much more general property of the experience being immediate—the experience being had in first-person style. As we’ve seen in answering the riddle of finding myself, the experience being immediate, being fist-person in style, is the only way I identify which being I am; and, as I am also saying, that is all that’s really involved in making something be me.”
Given what you write in “Relativity Theory for What the Future ‘You’ Is and Isn’t.” I think you would much enjoy the rest of Zuboff’s book.
Thanks, the suggestion sounds interesting. However; first quick update fwiw: I’ve only had the chance to read the first small section, “A Brief Proof at You Are Every Conscious Thing”, and I must say to me it seems totally clear he’s essentially making the same Bayesian mistake—or sort of Anthropic reasoning mistake—that OP contains. It’s totally not making sense the way he puts it, and I’m slightly surprised he published it like that.
I plan to read more and to provide my view on the rest of his argument—hopefully I’ll not fail despite time pressure.