Why should you not have preferences about something just because you can’t observe it? Do you also not care whether an intergalactic colony-ship survives its journey, if the colony will be beyond the cosmological horizon?
The depature of an intergalactic colony-ship is an observable event. It’s not that the future of other worlds is unobservable, it’s that their existance in the first place is not a testable theory (though see army1987′s comment on that issue).
To make an analogy (though admittedly an unfair one for being a more complex rather than an arguably less complex explanation): I don’t care about the lives of the fairies who carry raindrops to the ground either, but it’s not because fairies are invisible (well, to grown-ups anyway).
The depature of an intergalactic colony-ship is an observable event.
By the exact same token, the world-state prior to the “splitting” in a Many Worlds scenario is an observable event.
I think the spirit of the question is basically: In what situations do we give credence to hypotheses which posit systems that we can influence, but cannot influence us?
By the exact same token, the world-state prior to the “splitting” in a Many Worlds scenario is an observable event.
The falling of raindrops is also observable, you appear to have missed the point of my reply.
To look at it another way, there is strong empyrical evidence that sentient beings will continue to exist on the colony-ship after it has left, and I do not believe there is analogous evidence for the continued existence of split-off parallel universes.
The spirit of the question is basically this:
Can the most parsimonious hypothesis ever posits systems that you can influence, but cannot causally influence you? And if so, what does that mean for your preferences?
No, the spirit of the question in context was to undermine the argument that the untestability of a theory implies it should have no practical implications, a criticism I opened myself up to by talking about observability rather than testability. The answer to the question was redundant to the argument, which was why I clarified my argument rather than answer it.
But since you want an answer, in principle yes I could care about things I can’t observe, at least on a moral level. On a personal level it’s a strong candidate for “somebody else’s problem” if ever I’ve seen one, but that’s a whole other issue. Usually the inability to observe something makes it hard to know the right way to influence it though.
Let’s check: “I can only have preferences over things that exist. The ship probably exists, because my memory of its departure is evidence. The parallel worlds have no similar evidence for their existence.” Is that correct paraphrasing?
Before the ship leaves, you know that sometime in the future there will be a future-ship in a location where it cannot interact with future-you.
By the same token, you can observe the laws of physics and the present-state of the universe. If, for some reason, your interpretation of those laws involves Many Worlds splitting off from each other, then, before the worlds split, you know that sometime in the future there will be a future-world unable to interact with future you.
For future-you, the existence of the future-ship is not a testable theory, but the fact that you have a memory of the ship leaving counts as evidence.
For future-you, the existence of the Other-Worlds is not a testable theory, but if Many-Worlds is your best model, then your memory of the past-state of the universe, combined with your knowledge of physics, counts as evidence for the existence of certain specific other worlds.
In your Faeries example, the Faeries do not merit consideration because it is impossible to get evidence for their existence. That’s not true in the quantum bomb scenario—if we except Many Worlds, then for the survivors of the quantum bomb, the memory of the existence of a quantum bomb is evidence that there exist many branches with Other Worlds in which everyone was wiped out by the bomb.
So, the actual question should be:
1) Does Many-Worlds fit in our ontology—as in, do universes on other branches constructed in the Many-World format even fit within the definition of “Reality” or not? (For example, if you told me there was a parallel universe which never interacted with us in any way, I’d say that your universe wasn’t Real by definition. Many Worlds branches are a gray area because they do interact, but current Other Worlds only interact with the past and the present only interacts with future Other Worlds, not current ones )
2a) If we decide that the Other Worlds from Many Worlds qualify as “Real”, can Many Worlds ever be a hypothesis which is Parsimonious enough to not be Pascal-Wager-ish? The Faeries qualify as “Real” because they do cause the raindrops to fall, but because of the nature of that hypothesis it can never be parsimonious enough to rise above Pascal-Wager-thresholds. Is Many-Worlds the same way? (From your answer, I gathered that your answer is “yes”, but I disagreed with your reason—see paragraph that begins with “In your Faeries example...” which is why I pointed out that if you accept Many Worlds then you can have evidence that points to certain sorts of worlds existing in my first reply.)
2b) If we decide that the other branches do not qualify as Real, can we make a definition of reality that does not exclude light-cone-leaving-spaceships?
3) And how do we construct our preferences, in relation to what we have defined as “Real”? (For example, we could simply say that despite having an ontology that acknowledges all the branches of Many Worlds as Real, our preferences only care about the world that we end up in.)
The spaceship “exists” (I don’t really like using exists in this context because it is confusing) in the sense that in the futures where someone figures out how to break the speed of light, I know I can interact with the spaceship. What is the probability that I can break the speed of light in the future?
Then for Many Worlds, what is the probability that I will be able to interact with one of the Other Worlds?
I would not care more about things if I gain information that I can influence them, unless I also gain information that they can influence me. If I gain credence in Many Worlds, then I only care about Other Worlds to the extent that it might be more likely for them to influence my world.
We’re assuming you can’t break the speed of light or interact with the other worlds.
It’s a one-way influence. You can influence the spaceship before it leaves your light cone (you can give them supplies, etc). The MW argument is that you can influence parallel universes before they split off.
Let’s check: “I can only have preferences over things that exist. The ship probably exists, because my memory of its departure is evidence. The parallel worlds have no similar evidence for their existence.” Is that correct paraphrasing?
No, not really. I mean, it’s not that far from something I said, but it’s departing from what I meant and it’s not in any case the point of my reply. The mistake I’m making is persisting in trying to clarify a particular way of viewing the problem which is not the best way and which is leading us both down the garden path. Instead, please forget everything else I said and consider the following argument.
Theories have two aspects. Testable predictions, and descriptive elements. I would (and I think the sequences support me) argue that two theories which make the same predictions are not different theories, they are the same theory with different flavour. In particular, you should never make a different decision under one theory than under the other. Many Worlds is a flavour of quantum mechanics, and if that choice of flavour effects ethical decisions then you are making different decisions according to the flavour rather than content of the theory, and something has gone wrong.
Everything else I said was intended solely to support that point, but somewhere along the way we got lost arguing about what’s observable, what consitutes evidence and meta-ethics. If you accept that argument then I have no further point to make. If you do not accept it, then please direct comments at that argument directly rather than anything else I’ve said.
I’ll try to address the rest of your reply with this in mind in the hopes that it’s helpful.
If … your interpretation of those laws involves Many Worlds
You could equally have said “If your interpretation of the physics of raindrops involves fairies”. My point is that no-one has any justification for making that assumption. Quantum physics is a whole bunch of maths that models the behaviour of particles on a small scale. Many Worlds is one of many possible descriptions of that maths that help us understand it. If you arbitrarily assume your description is a meaningful property of reality then sure, everything else you say follows logically, but only because the mistake was made already.
You compare Many Worlds to fairies in the wrong place, in particular post-arbitrary-assumption for Many Worlds and pre-arbitrary-assumption for fairies. I’ll give you the analogous statements for a correct comparison:
the Faeries do not merit consideration because it is impossible to get evidence for their existence
The people of other worlds do not merit consideration because it is impossible to get evidence of their existance.
if we except Many Worlds...
If we accept fairies...
… the memory of the existence of a quantum bomb is evidence that there exist many branches with Other Worlds in which everyone was wiped out by the bomb
… the sight of a raindrop falling is evidence that there exists a fairy a short distance away.
Taboo “justification”. Justification is essentially a pointer to evidence or inference. After all the inference is said and done, the person who needs to provide more evidence is the person who has the more un-parsimonious hypothesis. You reject fairies based on a lack of justification because it’s not parsimonious. You can’t reject Many-Worlds on those same grounds, at least not without explaining more.
The difference is that the fairies interpretation of raindrops has different maths than the non-fairy interpretation of raindrops. When the mathematically-rigorous descriptions for two different hypotheses are different, there is a clear correct answer as to which is more parsimonious.
Many-worlds has exactly the same mathematical description as the alternative, so it’s hard to say which is more parsimonious. You can’t say that Single-World is default and Many Worlds requires justification. This is why I claim that it is first a question of ontology (a question of what we choose to define as reality), and then maybe we can talk about the epistemology and whether or not the statement is “True” within our definitions...after we clarify our ontology and define the relationship between ontology and parsimony, not before.
Why should you not have preferences about something just because you can’t observe it? Do you also not care whether an intergalactic colony-ship survives its journey, if the colony will be beyond the cosmological horizon?
The depature of an intergalactic colony-ship is an observable event. It’s not that the future of other worlds is unobservable, it’s that their existance in the first place is not a testable theory (though see army1987′s comment on that issue).
To make an analogy (though admittedly an unfair one for being a more complex rather than an arguably less complex explanation): I don’t care about the lives of the fairies who carry raindrops to the ground either, but it’s not because fairies are invisible (well, to grown-ups anyway).
By the exact same token, the world-state prior to the “splitting” in a Many Worlds scenario is an observable event.
I think the spirit of the question is basically: In what situations do we give credence to hypotheses which posit systems that we can influence, but cannot influence us?
The falling of raindrops is also observable, you appear to have missed the point of my reply.
To look at it another way, there is strong empyrical evidence that sentient beings will continue to exist on the colony-ship after it has left, and I do not believe there is analogous evidence for the continued existence of split-off parallel universes.
No, the spirit of the question in context was to undermine the argument that the untestability of a theory implies it should have no practical implications, a criticism I opened myself up to by talking about observability rather than testability. The answer to the question was redundant to the argument, which was why I clarified my argument rather than answer it.
But since you want an answer, in principle yes I could care about things I can’t observe, at least on a moral level. On a personal level it’s a strong candidate for “somebody else’s problem” if ever I’ve seen one, but that’s a whole other issue. Usually the inability to observe something makes it hard to know the right way to influence it though.
Let’s check: “I can only have preferences over things that exist. The ship probably exists, because my memory of its departure is evidence. The parallel worlds have no similar evidence for their existence.” Is that correct paraphrasing?
Before the ship leaves, you know that sometime in the future there will be a future-ship in a location where it cannot interact with future-you.
By the same token, you can observe the laws of physics and the present-state of the universe. If, for some reason, your interpretation of those laws involves Many Worlds splitting off from each other, then, before the worlds split, you know that sometime in the future there will be a future-world unable to interact with future you.
For future-you, the existence of the future-ship is not a testable theory, but the fact that you have a memory of the ship leaving counts as evidence.
For future-you, the existence of the Other-Worlds is not a testable theory, but if Many-Worlds is your best model, then your memory of the past-state of the universe, combined with your knowledge of physics, counts as evidence for the existence of certain specific other worlds.
In your Faeries example, the Faeries do not merit consideration because it is impossible to get evidence for their existence. That’s not true in the quantum bomb scenario—if we except Many Worlds, then for the survivors of the quantum bomb, the memory of the existence of a quantum bomb is evidence that there exist many branches with Other Worlds in which everyone was wiped out by the bomb.
So, the actual question should be:
1) Does Many-Worlds fit in our ontology—as in, do universes on other branches constructed in the Many-World format even fit within the definition of “Reality” or not? (For example, if you told me there was a parallel universe which never interacted with us in any way, I’d say that your universe wasn’t Real by definition. Many Worlds branches are a gray area because they do interact, but current Other Worlds only interact with the past and the present only interacts with future Other Worlds, not current ones )
2a) If we decide that the Other Worlds from Many Worlds qualify as “Real”, can Many Worlds ever be a hypothesis which is Parsimonious enough to not be Pascal-Wager-ish? The Faeries qualify as “Real” because they do cause the raindrops to fall, but because of the nature of that hypothesis it can never be parsimonious enough to rise above Pascal-Wager-thresholds. Is Many-Worlds the same way? (From your answer, I gathered that your answer is “yes”, but I disagreed with your reason—see paragraph that begins with “In your Faeries example...” which is why I pointed out that if you accept Many Worlds then you can have evidence that points to certain sorts of worlds existing in my first reply.)
2b) If we decide that the other branches do not qualify as Real, can we make a definition of reality that does not exclude light-cone-leaving-spaceships?
3) And how do we construct our preferences, in relation to what we have defined as “Real”? (For example, we could simply say that despite having an ontology that acknowledges all the branches of Many Worlds as Real, our preferences only care about the world that we end up in.)
The spaceship “exists” (I don’t really like using exists in this context because it is confusing) in the sense that in the futures where someone figures out how to break the speed of light, I know I can interact with the spaceship. What is the probability that I can break the speed of light in the future?
Then for Many Worlds, what is the probability that I will be able to interact with one of the Other Worlds?
I would not care more about things if I gain information that I can influence them, unless I also gain information that they can influence me. If I gain credence in Many Worlds, then I only care about Other Worlds to the extent that it might be more likely for them to influence my world.
We’re assuming you can’t break the speed of light or interact with the other worlds.
It’s a one-way influence. You can influence the spaceship before it leaves your light cone (you can give them supplies, etc). The MW argument is that you can influence parallel universes before they split off.
No, not really. I mean, it’s not that far from something I said, but it’s departing from what I meant and it’s not in any case the point of my reply. The mistake I’m making is persisting in trying to clarify a particular way of viewing the problem which is not the best way and which is leading us both down the garden path. Instead, please forget everything else I said and consider the following argument.
Theories have two aspects. Testable predictions, and descriptive elements. I would (and I think the sequences support me) argue that two theories which make the same predictions are not different theories, they are the same theory with different flavour. In particular, you should never make a different decision under one theory than under the other. Many Worlds is a flavour of quantum mechanics, and if that choice of flavour effects ethical decisions then you are making different decisions according to the flavour rather than content of the theory, and something has gone wrong.
Everything else I said was intended solely to support that point, but somewhere along the way we got lost arguing about what’s observable, what consitutes evidence and meta-ethics. If you accept that argument then I have no further point to make. If you do not accept it, then please direct comments at that argument directly rather than anything else I’ve said.
I’ll try to address the rest of your reply with this in mind in the hopes that it’s helpful.
You could equally have said “If your interpretation of the physics of raindrops involves fairies”. My point is that no-one has any justification for making that assumption. Quantum physics is a whole bunch of maths that models the behaviour of particles on a small scale. Many Worlds is one of many possible descriptions of that maths that help us understand it. If you arbitrarily assume your description is a meaningful property of reality then sure, everything else you say follows logically, but only because the mistake was made already.
You compare Many Worlds to fairies in the wrong place, in particular post-arbitrary-assumption for Many Worlds and pre-arbitrary-assumption for fairies. I’ll give you the analogous statements for a correct comparison:
The people of other worlds do not merit consideration because it is impossible to get evidence of their existance.
If we accept fairies...
… the sight of a raindrop falling is evidence that there exists a fairy a short distance away.
Taboo “justification”. Justification is essentially a pointer to evidence or inference. After all the inference is said and done, the person who needs to provide more evidence is the person who has the more un-parsimonious hypothesis. You reject fairies based on a lack of justification because it’s not parsimonious. You can’t reject Many-Worlds on those same grounds, at least not without explaining more.
The difference is that the fairies interpretation of raindrops has different maths than the non-fairy interpretation of raindrops. When the mathematically-rigorous descriptions for two different hypotheses are different, there is a clear correct answer as to which is more parsimonious.
Many-worlds has exactly the same mathematical description as the alternative, so it’s hard to say which is more parsimonious. You can’t say that Single-World is default and Many Worlds requires justification. This is why I claim that it is first a question of ontology (a question of what we choose to define as reality), and then maybe we can talk about the epistemology and whether or not the statement is “True” within our definitions...after we clarify our ontology and define the relationship between ontology and parsimony, not before.