Say you've got a friend who claims he's psychic. Telepathy, premonitions, past-life recall, you name it, he's done it. And not only does he always know who's on the phone before it rings, he modestly confesses -- he can psychically influence the world, too. Mind-over-matter, you see... or, to use the technical term, PK (from Psycho-Kinesis: Greek for 'movement based on the psyche'). The term "telekinesis" refers to the same phenomenon.
Now, you're an open-minded person, no doubt. You're even willing to believe that psychokinesis is true -- provided it can be scientifically proven and demonstrated. So, how do you go about testing this guy?
Not easy. Sure, you can try something obvious -- like putting your favorite beer-mug on a table, and challenge your friend to set it floating across the room, without touching it. Trouble is, if he succeeds, there's a very good chance he's found a way to cheat (better check into his past as a magician or illusionist). And if he fails, he'll protest -- quite rightly -- that that was much too difficult a test (plus, it takes hours to build up the necessary concentration, the psychological conditions weren't right, PK never works when Mars is retrograde... whatever).
Anyway, unless you have stumbled upon someone VERY gifted, chances are you won't get very far this way. But there are alternative ways to test for PK. Parapsychologists' preferred approach is to measure much subtler manifestations of mind-over-matter, detectable only through refined measurement techniques. So, before going for the big stuff, try determining whether your friend is capable of a microscopic influence upon objects or events.
To get started, you don't need anything fancy -- just a nice, shiny coin. A coin tumbling through the air has two equally probable outcomes: heads, or tails -- so, normally, there's just a 50-50 chance to correctly predict the outcome of the coin-toss. If you toss it a hundred times, then, by chance alone, the person should call it right just about half the time, give or take a few. But if your friend does have some psychic ability then he should be able to beat those odds, and get a much better score -- say, 65 'hits' (correct guesses) in 100 coin tosses.
Now, let's say he does - what does that mean? Well, for one thing, it might have been just a lucky streak; there's a chance, albeit a pretty small one, that that was a happy coincidence. Alternatively, it may show that he was indeed able to 'pick up' information psychically -- to predict the outcome through ESP -- but not necessarily force the coin towards that outcome using PK. So we've got to up the ante: we must pick either heads or tails in advance as the 'target' outcome, and then ask him to consistently 'force' that outcome upon the poor tumbling coin. So, you would try, say, 100 coin-tosses with heads as the 'target,' 100 tosses with tails as the target, and 100 'control' tosses, with no target at all. If toss outcomes keep favoring the selected 'target'-face -- the one your friend is currently wishing for -- then you might begin to suspect that something real is going on; especially if during the 'no-target' condition you get pretty close to a 50-50 distribution (showing you have a 'fair' coin).
PK generally evokes images of table levitations, spoons bending, and similar fireworks. But such 'macroscopic' or large-scale PK effects -- assuming they really exist -- are probably just the more explicit and impressive manifestations of a broader phenomenon which is going on all the time, unnoticed. Though macro-PK was the craze of late 19th century psychical research (and briefly in the 1970s, with Uri Geller and others), micro-PK - the mind's influence upon microscopic events -- has been the preferred laboratory approach for several decades now.
Actually, the idea of micro-PK is not new. Way back in the 1700s, Sir Francis Bacon, 'father' of the scientific method, gave some visionary suggestions for the study of micro-PK. In his posthumously published work ' Sylva Sylvarum ' he proposed we study this 'mental force' by applying it '...upon things that have the lightest and easiest motions... as upon the sudden fading or coming up of herbs; or upon their bending one way or other ...or upon the casting of dice'.
Bacon's ghost must have had something to do with the strange twist of fate which got micro-PK research going in the 1930s. A young gambler arrived at the Duke University parapsychology lab -- the first university lab fully dedicated to parapsychological research -- claiming he could influence the fall of dice by sheer ' will power '. J.B.Rhine, director of the lab and 'father' of modern parapsychology, was intrigued, and ready and willing. He devised tests using dice as 'target' systems, and found that the gambler indeed seemed to beat the odds and get the wished-for outcome much more often than would be expected by chance. Micro-PK research was thus born, as Rhine began to test different individuals' ability to influence the fall of dice.