## Paranormal phenomena: the problem of proof

Discussions on UFOs, ghosts, myths etc.

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### Re: Paranormal phenomena: the problem of proof

Thommo wrote:A link someone provided in another thread, which contains a particularly illuminating comment on how even a small scale effect which was intermittent and unpredictable would have massive effects at the observable scale:-

http://dl.dropbox.com/u/1018886/Bem6.pdf
To appreciate how unlikely the existence of psi really is, consider the facts that (a) casinos make profit, and (b) casinos feature the game of French roulette. French roulette features 37 numbers, 18 colored black, 18 colored red, and the special number 0. The situation we consider here is where gamblers bet on the color indicated by the roulette ball. Betting on the wrong color results in a loss of your stake, and betting on the right color will double your stake. Because of the special number 0, the house holds a small advantage over the gambler; the probability of the house winning is 19=37. Consider now the possibility that the gambler could use psi to bet on the color that will shortly come up, that is, the color that will bring great wealth in the immediate future. In this context, even small effects of psi result in substantial payoffs. For instance, suppose a player with psi can anticipate the correct color in 53.1% of cases—the mean percentage correct across participants for the erotic pictures in Bem’s Experiment 1. Assume that this psi-player starts with only 100 euros, and bets 10 euro every time. The gambling stops whenever the psi-player is out of money (in which case the casino wins) or the psi-player has accumulated one million euros. After accounting for the house advantage, what is the probability that the psi-player will win one million euros? This probability, easily calculated from random walk theory (e.g., Feller, 1970, 1971) equals 48.6%. This means that, in this case, the expected profit for a psychic’s night out at the casino equals \$485,900. If Bem’s psychic plays the game all year round, never raises the stakes, and always quits at a profit of a million dollars, the expected return is \$177,353,500.5

Clearly, Bem’s psychic could bankrupt all casinos on the planet before anybody realized what was going on. This analysis leaves us with two possibilities. The first possibility is that, for whatever reason, the psi effects are not operative in casinos, but they are operative in psychological experiments on erotic pictures. The second possibility is that the psi effects are either nonexistent, or else so small that they cannot overcome the house advantage. Note that in the latter case, all of Bem’s experiments overestimate the effect.

Very interesting argument! Especially when you think about it in relation to the, genuine, cases where people have exploited small mechanical biases in roulette wheels.
'To a thinking person, a paradox is what the smell of burning rubber is to an electrical engineer' - Sir Peter Medawar (adapted)
Will S

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### Re: Paranormal phenomena: the problem of proof

Will S wrote:
Thommo wrote:A link someone provided in another thread, which contains a particularly illuminating comment on how even a small scale effect which was intermittent and unpredictable would have massive effects at the observable scale:-

http://dl.dropbox.com/u/1018886/Bem6.pdf
To appreciate how unlikely the existence of psi really is, consider the facts that (a) casinos make profit, and (b) casinos feature the game of French roulette. French roulette features 37 numbers, 18 colored black, 18 colored red, and the special number 0. The situation we consider here is where gamblers bet on the color indicated by the roulette ball. Betting on the wrong color results in a loss of your stake, and betting on the right color will double your stake. Because of the special number 0, the house holds a small advantage over the gambler; the probability of the house winning is 19=37. Consider now the possibility that the gambler could use psi to bet on the color that will shortly come up, that is, the color that will bring great wealth in the immediate future. In this context, even small effects of psi result in substantial payoffs. For instance, suppose a player with psi can anticipate the correct color in 53.1% of cases—the mean percentage correct across participants for the erotic pictures in Bem’s Experiment 1. Assume that this psi-player starts with only 100 euros, and bets 10 euro every time. The gambling stops whenever the psi-player is out of money (in which case the casino wins) or the psi-player has accumulated one million euros. After accounting for the house advantage, what is the probability that the psi-player will win one million euros? This probability, easily calculated from random walk theory (e.g., Feller, 1970, 1971) equals 48.6%. This means that, in this case, the expected profit for a psychic’s night out at the casino equals \$485,900. If Bem’s psychic plays the game all year round, never raises the stakes, and always quits at a profit of a million dollars, the expected return is \$177,353,500.5

Clearly, Bem’s psychic could bankrupt all casinos on the planet before anybody realized what was going on. This analysis leaves us with two possibilities. The first possibility is that, for whatever reason, the psi effects are not operative in casinos, but they are operative in psychological experiments on erotic pictures. The second possibility is that the psi effects are either nonexistent, or else so small that they cannot overcome the house advantage. Note that in the latter case, all of Bem’s experiments overestimate the effect.

Very interesting argument! Especially when you think about it in relation to the, genuine, cases where people have exploited small mechanical biases in roulette wheels.

So we're basically saying here that because a Casino makes profit and doesn't go out of business we can say without a shadow of a doubt that there are no people in the world who posses "psi" capabilities, as you put it?
Hmmmmm.
Is it written somewhere that people who claim to posses "psi" capabilities are duty bound to try and make money from their abilities?

I'm sure this is relevant in terms of Bem's experiments, I'll be honest, I'm not familiar with them. I'm not so sure you can write off the chance that there are indeed people who posses abilities that would you label "psi" abilities?
science_is_god

Name: Tom
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### Re: Paranormal phenomena: the problem of proof

nojesusknowpeace wrote:If paranormal activity can't be proven, then its existence like, its usefulness, is irrelevant.
If even after exhaustive study, the presence of ghosts, spirits,etc or the ability to see the future can't be tested because of their "transient nature" then they have little if any value and are better off being ignored.
That's what I took away from the article.

So what would you say is the use of logic and science? Yes, I am actually asking this.....

Cheers
science_is_god

Name: Tom
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Country: England
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### Re: Paranormal phenomena: the problem of proof

science_is_god wrote:So we're basically saying here that because a Casino makes profit and doesn't go out of business we can say without a shadow of a doubt that there are no people in the world who posses "psi" capabilities, as you put it?
Hmmmmm.
Is it written somewhere that people who claim to posses "psi" capabilities are duty bound to try and make money from their abilities?

I'm sure this is relevant in terms of Bem's experiments, I'll be honest, I'm not familiar with them. I'm not so sure you can write off the chance that there are indeed people who posses abilities that would you label "psi" abilities?

No, I'm not saying anything like that. I agree with the man I quoted in the OP - which is why I quoted him.

If we assume that paranormal abilities operate at a statistically low level and in a spasmodic way, then proving their non-existence is likely to be impossible.

On the other hand, if they operated spasmodically, but at a statistically high level, or if they operated in a regular way at a statistically low level, then it seems pretty clear that we would, by now, have ample evidence for their existence.

Likewise, I suppose it's a logical possibility that people who are blessed with paranormal powers are never tempted to use them for personal gain - so they steer clear of casinos. That might explain why casinos are able to operate profitably. (But I see Occam approaching, waving his razor in a menacing manner ... Best stop!)
'To a thinking person, a paradox is what the smell of burning rubber is to an electrical engineer' - Sir Peter Medawar (adapted)
Will S

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### Re: Paranormal phenomena: the problem of proof

Will S wrote:Likewise, I suppose it's a logical possibility that people who are blessed with paranormal powers are never tempted to use them for personal gain
It is indeed possible (not automatically plausible, mind you) that psychic powers manifest as a result of some anomaly (most likely that would be in the brain) that also makes the psychics abnormally reticient in applying their abilities to take advantage of any person, organization or whathavewe. One notes this also should rule out each and every "psychic" (most especially Uri Geller ) who takes any sort of payment (in money or otherwise) from the people who they employ their powers fróm having actual bona fide psychic powers, thus making them charlatans.
The dog, the dog, he's at it again!
tnjrp

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### Re: Paranormal phenomena: the problem of proof

The true psi masters have the power to make others blind to their psi activity. Even if someone spots their anomalous behaviour they will know and make the witnesses forget what they saw and blame it on "coincidence" (there is no such thing!).

[/sarcasm]
Why do you think that?
GrahamH

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### Re: Paranormal phenomena: the problem of proof

science_is_god wrote:So we're basically saying here that because a Casino makes profit and doesn't go out of business we can say without a shadow of a doubt that there are no people in the world who posses "psi" capabilities, as you put it?
Hmmmmm.
Is it written somewhere that people who claim to posses "psi" capabilities are duty bound to try and make money from their abilities?

I'm sure this is relevant in terms of Bem's experiments, I'll be honest, I'm not familiar with them. I'm not so sure you can write off the chance that there are indeed people who posses abilities that would you label "psi" abilities?

No, but then we can't rule out with a shadow of a doubt the chance that every one of your posts is a glitch in the server database generating a random string of letters that just happens to give the impression of being English. However at some point of probability and lack of parsimony, it is necessary to avoid making unlikely assumptions.

Thommo

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