if P(B) is well defined without reference to A

You're right. Good point.

it's an n-squared-minus-one-way street

Don't you mean n-factorial? Anyway, ... hmm, I need to think about this more.

Hi lisper,

I found your paper easy to follow and maybe insightful (I'll have to read it more carefully the second time) but like qmotus, I don't understand your reasoning in this thread. I'm assuming MWI is just an interpretation of unitary QM, so makes all the same mathematical predictions as other non-collapse theories. And the roulette story is just one way of looking at it, from the perspective of what I consider my (classical) self and what I call the future.

Since you are not claiming that QIT makes different mathematical predictions than MWI, how can you claim they make different predictions at all?

I would say that a major difference between MWI and various collapse interpretations is that there are situations where according to collapse interpretations there most likely will be no future you; but according to MWI there surely will, although their amplitude is low (the aforementioned Russian roulette is one such situation, for instance). I find it somewhat difficult to think about those from the perspective you advocate.

Well, I'd rather say that I will perceive being every one of them; it's just that no future me will perceive being more than one of the future mes. The terminology gets quite confusing here, but I think the Quantum Russian Roulette you mentioned (and quantum suicide and immortality, by extension, for example) is one situation where this aspect of quantum theory becomes somewhat apparent, which is why I think it would be interesting if you elaborated a bit more on how you think the predictions QTI and MWI make differ from each other.

Multiple-worlds is mathematically tenable, but it has some very serious problems as an explanatory theory and it makes predictions that even its adherents seem unwilling to accept.

Doesn't the QIT you describe make the exact same predictions, also the Russian roulette you mentioned?

But there is one classical reality that is privileged to me because it happens to be the one that I'm living in, which is to say, it's the reality that is mutually entangled (and therefore classically correlated) with the massively-mutually-entangled system that is me. In an absolute sense I am no more or less real than all the other potential mes that you get by slicing up the wave function in different ways, but I don't care about that except in the abstract.

But there's no single privileged future you, right?

How far does it go in solving the measurement problem? Can you derive the Born rule? Can you settle the single/many world dichotomy?

That's what "causal relationship" means.

I disagree. Following Pearl, I define "A causes B" to mean something like: (DO:A) raises the probability of B.

Bob's choice in the evening to make strong measurements along the beta-axis, raises the probability of Alice's noon measurements along the beta-axis measurements having been the ones that showed the best correlation. It doesn't raise the probability of any individual measurement being up or down, but that's OK. Even on a many worlds interpretation, where perhaps every digital up/down pattern happens at some "world" and the overall multi-world distribution is invariant, "probability" refers to what happens in our "world", so again that's OK.

Correlation can only be observed after the fact, in the evening, not at noon. So isn't this just a case of Bob affecting Bob+Alice's immediate future, where they go over the results? Why do I say Bob's choice affected Alice's results? Because correlation is a two-way street, and in this case there isn't much traffic in the forward direction. Alice's measurements only weakly affect Bob's results.

That's a red herring. The question was not how she could have known that God was an authority figure. The question was how she could have known that the snake was NOT an authority figure too.

Oh, right. Hmmm. Good question.

...I want to say that it's common sense that not everyone who claims to be an authority figure is one, and that preferably one authority figure should introduce another on first meeting. But... Eve may well have been only hours old, and would not have any experience to back that up with.

Oh, come on. Even if we suppose that God can get bored, you really don't think he could have come up with a more effective way to spread the Word than just having one-on-one chats with individual humans? Why not hold a big rally? Or make a video? Or at least have more than one freakin' person in the room when He finally gets fed up and says, "OK, I've had it, I'm going to tell you this one more time before I go on extended leave!" ???

There are plenty of ways to handle it, yes. All of which work very well for one generation. Twenty, thirty years' time there's a new batch turning up. One either needs a recording or, better yet, get them to teach their children...

everyone would recognise the man who could not grow crops, and know he'd killed his brother

You do know that this is LessWrong, right? A site dedicated to rationality and the elimination of logical fallacies and cognitive bias? Because you are either profoundly ignorant of elementary logic, or you are trolling. For your reasoning here to be valid it would have to be the case that the only possible reason someone could not grow crops is that they had killed their brother. If you can't see how absurd that is then you are beyond my ability to help.

Yes, I know exactly what site this is. Yes, I know that the reasoning "he can't grow crops, therefore he killed his brother" is badly flawed. But the question is not whether people would think like that. The question is why would Cain, a human with biases and flawed logic, why would he think that people would reason like that?

And I think that the answer to that question is, because Cain had a guilty conscience. Because he had a guilty conscience, he defaults to expecting that, if anyone else sees something that is a result of his crime, they will correctly divine the reason for what they see (Cain was very much not a rationalist).

I don't think that there is any evidence to suggest that anyone else actually thought like Cain expected them to think.

Because "the good stuff" is essential to our survival. Humans cannot survive without cooperating with each other. That's why we are social animals. That's why we have evolved moral intuitions about right and wrong.

On a tribal level, yes, a cooperative tribe will outcompete a "pure evil" tribe easily. But even the "pure evil" tribe might hang around for two, maybe three generations.

I'm not claiming they'd be able to survive long-term, by any means. I just think one generation is a bit short.

What difference does that make? Yes, 14B years is a long time, but it's exactly the same amount of time for a computer. However much humans can calculate in 14B years (or any other amount of time you care to pull out of your hat) a computer can calculate vastly more.

That is true. However, in this case, if the universe if a computer, then the computer appears to have just sat around and waited for the first 14B years doing nothing. If it's intended to find the answer to some question faster than its creator could, then it must be a pretty big question.

I've been to SA twice. Beautiful country, but your politics are even more fucked up than ours here in the U.S., and that's saying something.

Yeah... wonderful climate, great biodiversity, near-total lack of large-scale natural disasters (as long as you stay off the floodplains), even our own private floral kingdom... absolutely horrible politicians.

If you don't care what I believe then you are under no obligations

As a matter of fact, I think the free will question is an interesting question, but not an instrumentally important question; I can't really think of anything I would do differently if I were to change my mind on the matter. This is especially true if you are right - in that case we'd both do whatever we're going to do and it wouldn't matter at all!

Free will and consciousness are both real subjective experiences, but neither one is objectively real. Their natures are very similar. I might even go so far as to say that they are the same phenomenon.

Interesting. The reason I asked the question is that there are some thinkers who deny the reality of free will but accept the reality of consciousness (e.g. Alex Rosenberg); I was curious if you are in that camp. It sounds as though you are not.

I recommend reading this book if you really want to understand (consciousness).

Glad to see you are open to at least some of Daniel Dennett's views! (He's a compatibilist, I believe.)

It's not that deep. It (the idea that the feeling that you are living in a classical Galilean universe is a perceptual illusion) just means that your perception of reality is different from actual reality in some pretty fundamental ways. The sun appears to revolve around the earth, but it doesn't. The chair you're sitting on seems like a solid object, but it isn't. "Up" always feels like it's the same direction, but it's not.

Understood. My confusion came from the term "Galilean Universe" which I assumed was a reference to Galileo (who was actually on-board with the idea of the Earth orbiting the Sun - that is one of the things that got him into some trouble with the authorities!)

1. There are many perceptual illusions

I agree with that

so the hypothesis that free will is an illusion is not a priori an extraordinary claim

I basically agree with that too - it is you rather than me who brought up the notion of extraordinary claims. It seems to me that the notion of extraordinary claims in this case is a red herring - that free will is real is a claim, and that free will is not real is a claim; I am simply arguing that neither claim has a greater burden of proof than the other. In fact, I think that there is room for reasonable people to disagree with regard to the free will question.

In fact, the feeling that you are living in a classical Galilean universe is a perceptual illusion!

I don't know what that means exactly, but it sounds intriguing! Do you a link or a reference with additional information?

2 There is evidence that free will is in fact a perceptual illusion

None of those experiments provides strong evidence; the article you linked lists for several of the experiments objections to interpreting the experiment as evidence against free will (e.g., per the article, "Libet himself did not interpret his experiment as evidence of the inefficacy of conscious free will"). One thing in particular that I noticed is that many of the experiments dealt with more-less arbitrary decisions - e.g. when to flick one's wrist, when to make brisk finger movements at arbitrary intervals, etc. Even if it could be shown that the brain somehow goes on autopilot when making trivial, arbitrary decisions that hold no significant consequences, it is not clear that this says anything about more significant decisions - e.g. what college to attend, how much one should spend on a house, etc.

3 It makes evolutionary sense that the genes that built our brains would want to limit the extent to which they could become self-aware. If you knew that your strings were being pulled you might sink into existential despair, which is not generally salubrious to reproductive fitness.

That is a reasonable statement and I have no argument with it. But, while it provides a possible explanation why we might perceive free will even if it does not exist, I don't think that it provides significant evidence against free will.

4 We now understand quite a bit about how the brain works and about how computers work, and all the evidence indicates that the brain is a computer. More precisely, there is nothing a brain can do that a properly programmed Turing machine could not do

I agree with that.

and therefore no property that a brain have that cannot be given to a Turing machine. Some Turing machines definitely do not have free will... So if free will is a real thing you should be able to exhibit some way to distinguish those Turing machines that have free will from those that do not.

If that statement is valid, then it seems to me that the following statement is also valid:

"There is no property that a brain can have that cannot be given to a Turing machine. Some Turing machines definitely are not conscious. So if consciousness is a real thing you should be able to exhibit some way to distinguish those Turing machines that are conscious will from those that are not."

So, do you believe that consciousness is a real thing? And, can a Turing machine be conscious? If so, how are we to distinguish those Turing machines that are conscious will from those that are not?