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Pierre-Normand

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Indeed. And just as is the case with Newcomb's problem, with the two-envelope paradox also, the dominance principle and the (maximum) expected utility...
August 01, 2018 at 00:50
Probability is a big philosophical topic. It is quite tightly enmeshed with both metaphysics and epistemology. Michael Ayers wrote a lovely book, The ...
July 31, 2018 at 23:28
No, that's not what I was saying. I was rather suggesting that, assuming there is some determinate albeit unknown probability distribution of possible...
July 31, 2018 at 23:05
It does have some philosophical implications. Some of @"andrewk"'s replies raised good philosophical points regarding the status and significance of p...
July 31, 2018 at 22:54
Yours isn't really a decision tree that the player must make use of since there is no decision for the player to make at the first node. Imagine a gam...
July 31, 2018 at 22:25
This works if you are treating all the possible lower and upper bounds of the initial distribution as being equally likely, which is effectively the s...
July 30, 2018 at 00:18
No. The conditional expected values of switching conditional on v = 10, and conditional on 10 being either at the top, bottom or middle of the distrib...
July 29, 2018 at 22:40
Which is why you have no reason to switch, or not to switch. It may be that your value v is at the top of the distribution, or that it isn't. The only...
July 29, 2018 at 22:22
But then, if you agree not to disregard the amount of the improbable jackpot while calculating the expected value of the lottery ticket purchase, then...
July 29, 2018 at 22:14
Unless we are considering that the player's preference is being accurately modeled by some non-linear utility curve, as @"andrewk" earlier discussed, ...
July 29, 2018 at 21:59
There is another difference between the two methods @"JeffJo" presented, as both of them would be applied to the determinate value that is being obser...
July 29, 2018 at 21:40
Yes, you are justified in treating the "cases" (namely, the cases of being dealt the largest or smallest envelope within the pair) as equally likely b...
July 29, 2018 at 12:52
Sure. We can consider a distribution that is bounded on both sides, such as (£10,£20,£40,£80), with envelope pairs equally distributed between ((£10,£...
July 29, 2018 at 12:16
That's only true if £10 isn't at the top of the distribution. When the bounded and uniform distribution for single envelope contents is for instance (...
July 29, 2018 at 11:55
Sure, you will never know for sure that the value that you get is close to the top of the distribution. But the main point is that you will have no re...
July 29, 2018 at 11:21
If the distribution is somewhat uniform with an unfathomably large (albeit finite) upper bound, and you know this, then you can't generally expect to ...
July 29, 2018 at 11:14
The practical limitations indeed go against the spirit of the idealized two-envelopes problem. That's because if the prior distribution is bounded, al...
July 29, 2018 at 10:49
Sure, but it is one thing to say that it is rational (or isn't irrational) to switch when you find X in your envelope ($10,000 say) and it is another ...
July 29, 2018 at 10:32
Yes, that is roughly true for some mid-range values of X. See the second paragraph of my edited post for more discussion about real cases.
July 29, 2018 at 10:27
I am fine with acknowledging that there isn't any such thing as the rational decision to make in the vaguely specified case where you merely have a re...
July 29, 2018 at 10:18
If there exists some bounded and normalized (meaning that the probabilities add up to 1) prior probability distribution that represents your expectati...
July 29, 2018 at 10:04
What I criticized merely was a failure to draw a logical inference from one particular application of the principle of indifference. The logical infer...
July 29, 2018 at 09:38
Not at all. I have rather argued that there is an 1.25X expected gain from switching in one specific case of a known distribution {{5,10},{10,20}} whe...
July 29, 2018 at 09:24
I have chosen a third option, which is to point out the logical flaw in your purported identification of "the flaw". As I suggested earlier, your own ...
July 29, 2018 at 08:33
This is something I have never disputed. I have never purported to offer an optimal strategy or suggested that there is any way to come up with one. T...
July 29, 2018 at 08:24
When I say that this can be inferred from that, or that it is fallacious to infer this from that, then I am either right or wrong about it; and in the...
July 29, 2018 at 08:02
None of my arguments relied on being able to lean "much" about a distribution from one single observation. My arguments rather relied entirely on logi...
July 29, 2018 at 07:59
It is rational to want to maximize your expectation even when you only get one single chance to play, and it is irrational to dismiss your expectation...
July 29, 2018 at 07:37
It is rather difficult to divorce discussion of probabilities from discussion of statistics. You can't really build an insulating wall between those t...
July 29, 2018 at 07:35
Of course "only one case is true" at each iteration of the game. Still, the player doesn't know which one is true at each iteration of the game when h...
July 29, 2018 at 07:21
There is a sort a move in philosophy that is called "proving too much". An argument proves to much when it succeeds in proving the thesis that one pur...
July 29, 2018 at 07:04
No. You seem to be reaching for an argument that purports to show that your raised expectation from switching, conditionally on having found out that ...
July 29, 2018 at 06:24
You just said "The envelopes cannot be in both cases at once", followed with the word "therefore...". So it looked like you were making an issue of th...
July 29, 2018 at 06:09
The argument that purports to show that the expectation from switching is 1.25X doesn't rely on both possible cases (possible consistently with the in...
July 29, 2018 at 05:47
It doesn't really matter for what? It does matter for invalidating the fallacious argument that purports to show that your expected gain from switchin...
July 29, 2018 at 05:18
Sure, but that's not what the equiprobability assumption is. What I have been referring to as the equiprobability assumption is the assumption that yo...
July 29, 2018 at 05:11
1/2
July 29, 2018 at 05:00
Things have blown up long ago. It is precisely the endemic oversight of the logical dependency at issue that is the source of the apparent paradox bei...
July 29, 2018 at 04:22
To ignore logical dependencies between claims in rational arguments is a recipe for disaster.
July 29, 2018 at 04:07
I know that. But assumptions regarding the method for filling up the possible envelope pairs (and hence their distribution) entail logical consequence...
July 29, 2018 at 03:51
OK. Once one is reminded that such an 'uninformed' prior, regarding the initial possible contents of the envelopes, isn't reasonable, then, it follows...
July 29, 2018 at 03:44
Yes, for sure, but if someone hands me, as a gift, an envelope containing some unknown amount of dollars for me to keep, an 'uninformative' prior that...
July 29, 2018 at 03:35
I was rather careless in this post where I had made use of Hilbert's Grand Hotel for illustrative purpose. In my thought experiment the equiprobabilit...
July 29, 2018 at 03:27
The best way to counter that assumption, it seems to me, just is to remind oneself that even though one may not know what the distribution is, assumin...
July 29, 2018 at 02:47
If you are talking about Don Jr's statement about the meeting (being about adoption, etc.), then it's more than a strong rumor that Donald J. Trump he...
July 27, 2018 at 07:21
Yes, it is indeed the strange behavior of infinity that generates the paradox. (Edit: Opps, there are some mistakes below that I'll correct later toda...
July 27, 2018 at 06:10
Yes, yes and yes, but the assumption isn't merely unwarranted, it is impossible that it be true in any real world instantiation of the problem where t...
July 27, 2018 at 05:18
For sure, I agree, since any non-uniform prior would violate the equiprobability condition that alone grounds the derivation of the unconditional 1.25...
July 27, 2018 at 04:13
That's clever.
July 27, 2018 at 02:52
I disagree. Suppose you were to engage in one million iterations of that game and find that the seen envelope contents converge on a specific and roug...
July 27, 2018 at 02:26