One of my friends recently confided in me (by which he told me over the phone, rather than on Facebook for all the world to see) that he took spiritual and superstitious explanations of the world seriously, because of an experience he'd had when he was younger. He used to play (as did I, obsessively) a football management computer game called Championship Manager, in which you choose a football team to manage and guide them to glory - or ignominy, as the case may be. But he fervently believed that he could go into another room, sit in a particular position that somehow felt right, and this action would influence the result of the match on the computer - it would allow him to win.
He didn't go into great detail about any other such experiences he'd had, although I'm sure, being of such a persuasion, they must have occurred to him. But that seems to be the basis for his beliefs in things like the theories of David Icke, and other supernatural explanations for existence. It's experiences like these that drive him to believe in some higher power - that there must be soem purpose to our lives.
I disagree. I dislike trying to skewer someone's obviously cherished beliefs to their face, but question marks were flashing in my mind even as he spoke.
For one thing, a football management game isn't strictly a game of chance. You pick your team, choose your tactics, and let them loose on rival teams. I know, because I spent countless days of my life doing the exact same thing. Gradually, you build up expertise, and buy better players, until you've got a team capable of beating the world. This was my experience. I could then have happily started a match, gone off downstairs to make a cup of tea, and returned to the screen to find a 5-0 victory awaiting. There was no luck involved, it was almost entirely perseverance and knowledge.
I don't suspect he did a controlled, blinded trial either, he just trusted in his feelings. Ben Goldacre posted on the illusions of control this weekend - it's terribly easy to fall into the trap of believing that somehow, skill, or some other agent, had a part to play in an outcome that on reality was only the result of blind chance. It's a simple task for our brains to weed out results that don't fit our preconceived ideas, and record only what conforms to what we expect.
Two other of my friends told me about an experience they'd had going to see a psychic medium show - they'd gone with their respective partners, and had ended up with tickets sitting next to each other. It doesn't take much for people to be impressed - what if they'd been sitting on seats on the other side of where they were sitting? Or a row in front, or behind? How big was the hall, exactly - how many chairs? Mathematically, what was the likelihood that they would end up sitting, if not next to, then very close to each other?
Mathematics can play a huge part in convincing us that some agent is causing a coincidence, rather than pure blind chance. The birthday problem is a great example of this. Assuming that everyone has the same chance of being born on any given day of the year, it only takes 23 people gathered in the same room to create a 50% probability of two of those people sharing the same birthday. Raise that number to 57, and the probability rises dramatically, counter-intuitively, to 99%.
Correlation does not always imply causation. A and B might invariably occur together, but that does not mean to say that A 'causes' B. B might very well cause A. Or an as yet unconsidered variable, C, might cause both, or perhaps a combination of D and E. Or maybe A and B might be entirely unrelated. But we so often make the illogical leap of faith to confirm our beliefs and superstitions.