"Instead of thinking about telepathy from a present perspective, as in 'we have/use it now,' consider it from an evolutionary standpoint.
Prehistoric humans with even a little telepathy would have enormous survival advantage. You'd be able to tell whether a predator was hiding behind the next rock, or whether it's an animal you're hunting for food. Or nothing, in which case you go off and hunt somewhere else.
In that case, natural selection would at the same time pressure animals, both predators and prey, to evolve to a form where they could block the effect so that their adversary (human or other) would have no idea where they were hiding.
Even if we can't tell where animals are hiding, even a little telepathy between humans could be used in group hunting and teaching offspring, or summoning help in a dire emergency. Even a brief feeling which influences your actions based on information from another human would confer enormous advantage.
Some people have reported that they have gotten 'feelings' that some loved one is in trouble, but frankly there is an overwhemingly enormous number of dire incidents throughout human history, each one of which would select for having the telepathic trait. Something as simple as children having the ability to alert their parents that they are in trouble would still confer enormous survival advantage.
From an evolutionary perspective, telepathy is a strong survival trait. Since we don't see it in the gene pool, it's unlikely that it's even possible."
Sesticulus raises a similar idea in a more compact form (it could be called the haven't been slapped" argument): "Invariably if I'm in a public place, there will be someone I find attractive and I will think "hey now". I've never had someone come up and slap me for thinking rude thoughts, so at the very least, women I find attractive, as a rule, do not have telepathy."
Reader seanellis writes with his prediction of the experiment's outcome:
"This experiment is very poorly controlled (who's to say that two people aren't also on the phone to one another, for example?), and some startlingly accurate correlations will occur. These will be debunked as the players come under scrutiny and the communication channels between players are detected.
However, after these have been removed, some correlations between players will still remain, below the level of statistical significance. Rather than being dismissed as insignificant, the woo-woo crowd will seize on these random correlations as 'proof of need of more research.'
This prediction is not the result of clairvoyance, rather it is an educated guess based on previous observations of this kind of setup."
Even more dubious, dpbsmith writes not to "discount the possibility of outright fraud," asking: "Are they planning to strip-search the participants for hidden transmitters and receivers? To test and debug the system, have they hired a couple of good magicians skilled at 'mentalist' acts, with a promise to pay them well for their time if they can successfully cheat? Or, like most scientists, are they just protecting against unconscious cheating by honest, good-faith participants?"
Further, dpbsmith is disappointed that the article "doesn't really discuss the possibility of conscious, clever cheating... or implies that it's impossible because, well, gee, the system is so high-tech. ... People have smuggled transmitters and receivers into casinos, where the management is probably far more savvy, cynical, and experienced at detecting cheating — and financially motivated to do so — than these scientists."
Reader mdkemp took issue with the implication in some readers' comments that this research was disreputable, pointing out that such research is also undertaken "at respected institutions," writing: "Research into this stuff isn't just for [k]ooks and crazies -- even Princeton has a small lab the goal of which is to experimentally gather a 'better understanding of the role of consciousness in the establishment of physical reality.' It's called the 'Princeton Engineering Anomalies Research' (PEAR) lab, and its web page can be found at princeton.edu/~pear."
This met with an acerbic response from reader aepervius, who calls PEAR "a laughing stock" with "bad hypotheses, bias, bad statistical analysis, etc." He points out critical reports critical of PEAR at skepdic and at the Skeptic Report.
Reader RexRhino expressed a common sentiment:
"Can someone tell me why this isn't as outrageous as spending tax money to research 'intelligent design'? I mean, there is no real scientific theory that describes how telepathy would work, and virtually all scientific evidence says that telepathy doesn't exist. Telepathy is pretty much to fortune telling what Intelligent Design is to creationism — turning superstition into pseudo-science to make it palatable to the modern audience. I realize that England doesn't have the same strict legal seperation between religion and state as other countries, but even if research into the mystical and supernatural isn't strictly illegal it is certainly a questionable use of taxpayer money, no? Why are people outraged over Intelligent Design but not this kind of stuff?"
Reader Pyromage provided one answer to that question, writing: "Because it's possible to devise an experiment that could provide scientific evidence in its favor. ... Such an experiment does not — even in theory — exist for [Intelligent Design]."
Other responses to the story show that at least many Slashdot readers are none too happy with research into telepathy being done with tax monies. A long thread on that very topic raised several good points:
Reader denoir kicked off this thread with a sarcastic call to "invest some more tax money on finding UFOs, the Loch Ness Monster and inventing the perpetuum mobile!"
To this, reader misleb responded "I'm always been surprised at the kind of reaction anything labeled 'paranormal' gets from rational people. Why exactly couldn't telepathy exist? Is there some fundamental law of nature which states that two people cannot communicate over a distance without sound or visual cues? Obviously, you'd have to identify a mechanism for the communications. If telepathy exists, it isn't magic. ... If you had told someone from 200 years ago that you could communicate with people across the globe in real-time, they'd probably think you were some kind of sorcerer. But since then we've discovered radio waves..."
Reader Alsee has a satirical reponse: "Why exactly couldn't invisible pink unicorns exist? Is there some fundamental law of nature which states that invisible pink unicorns cannot exist? Obviously, you'd have to identify a mechanism for invisible pink unicorns. If invisible pink unicorns exist, it isn't magic. ... Telepathy, invisible pink unicorns, elves, Zeus, telekenesis, Narnia, rain dances, flying potions, the Tooth Fairy, I'm always surprised at the reaction of rational people when they think that these things do not exist."
Wavicle offers another reason for the widespread skepticism about such research:
"While there may be some out there shouting paranormal things couldn't possibly exist, most of us are just pissed. Pissed that for every genuinely deluded person who believed they had witnessed a paranormal event, there are 20 others out there looking at using it to scam people out of money.
We have looked, and looked, and looked and come up empty handed EVERY TIME. The vast majority of the people who have said they had special powers were LIARS. The rest were just wrong. Nobody has ever passed muster. There are people out there doing genuine harm to others under the veil of paranormal abilities.
For example EVERY instance of 'psychic surgery' (where someone performs surgery with just their hands, leaving behind no scar or wound) has been a scam for money."
The same corner of the discussion led to a freewheeling exchange of comments on scientific credulity and exotic explanations for telepathy involving quantum mechanics.
Reader kfg writes "I am, at least nominally, a physicist. You wouldn't catch me saying any such thing as 'telepathy can't exist.' However, you first need to demonstrate that it does exist if you expect me to do work on that basis. If and when that happens I will not posit any 'paranormal' event, but rather that there is a quite normal mechanism at work. Then it will be my job to find it, because, at the moment, there is no valid theory of such a mechanism. ('Well, maybe it could be ...' is not a theory.) A theory is model that is concordence with data. ... Which brings us back to the need to show me it exists, particularly since everything I have ever seen so far indicates that the world works just spiffily in accordance with the rules of chance."
Reader Thing 1 asserts "if the human brain works on quantum principles, and one of those principles is communication at a distance, then that tells me that telepathy is possible," and mentions the phenomenon of entanglement as a mechanism for instantaneous communication: "Through a process, two electrons become 'entangled,' and when separated experimentally up to 10 km, when the spin on one is changed, the spin on the other is changed immediately--with no speed-of-light delay."
To this, reader aardvarkjoe responds that "The problem is that, in these 'entanglement experiments,' no information is being transmitted from the first site to the second. By measuring the state of the first electron, you can instantaneously affect the state of the second electron — but according to all of the current theories, there is no way to actually use that to communicate. (If that sounds weird ... it is. Quantum theory is rather unintuitive.)"
Several readers' comments were not about the experiment at issue in this case, but rather about the James Randi Educational Foundation prize I mentioned. Two comments in particular sum up many of the others: Reader nido calls Randi a fraud with an agenda" and says this is how Randi is viewed by "people who can," to which Mr2001 responds "Well, there's also the slight difference that he has facts on his side. None of these so-called 'people who can' have ever been able to demonstrate their alleged abilities under controlled conditions. Until they can do that, they're nothing more than 'people who lie to others,' or at best, 'people who lie to themselves.' ... It's a pity that there's no evidence that these experiences actually took place in reality, not just in the participants' imaginations, don't you think? Because if there were evidence, someone would be a million dollars richer."
Many thanks to everyone who took part in the discussion, in particular those readers whose comments are quoted above.