22 November, 2011
Probability and possibility
Which is fine by me in principle, though my own recent experience does give me pause to reflect that things are not always as straightforward as they seem.
Let me tell you a story. To slightly misquote the title sequence of White Hunter*, a true story that actually happened.
Earlier this year two women knocked on my front door. I was perhaps a little slow in answering and I arrived at the door just as a key was turning in the lock and the door began to open. They had lost patience and decided to try out a key they had with them.
Once order had been restored, with my unorthodox visitors confined peremptorily to the doorstep, they explained themselves. They were, they told me, respectively the sister and niece of a gentleman who had formerly lived more or less here. I say "more or less here" because they were not absolutely sure of the correct address. My house was one of a range of adjacent possible addresses which they had.
It was never made precisely clear what had happened to this gentleman — for the sake of argument let's call him Mr Pendleton — but the gist of it seemed to be that
- He had been a tenant of a house in the immediate vicinity, who had left a few months before.
- He was either dead or otherwise no longer able to manage his own affairs, or at least to visit himself.
- This pair, his relatives, were here to check out his former home for important personal items or documents and generally bring his presence here to an orderly close.
A few days later they were back. Although they didn't say so directly, they had clearly been to the police in the interim, who had obviously not been particularly helpful. Although their accents were native English, they actually lived abroad and only had a couple of days further in London. And they had run out of options. The two things they did have were an approximate match with my address and a key which fitted my door.
The copper they had spoken to had told them that a co-incidental match of someone else's key with my lock was "a million to one against". The copper was talking off the top of his head. I was, unsurprisingly, interested in that probability as well and had been doing some research. A wonderful tool, the web. Not perfect by any means but it has its moments. My front door lock is a of a very common design from a major brand. My best estimate is that there are actually no more than 1000 to 2000 different keys for that brand and design of lock in actual circulation. In practice, if you think about it, that is perfectly adequate.
This information cut no ice, of course. That the key fitted was proof positive that they had found their target. I showed my visitors letters addressed to me at this address along with photo-ID which matched my name to my image.
This did not satisfy them. I could understand why. They were under pressure: if my house wasn't the one they sought, then their mission had failed and they would have to go home — a long and expensive way away — empty handed. And the prima facie evidence of the matching key was very strong, too strong, despite the rational truth of the fact that improbability is not the same thing as impossibility. But we were going nowhere. I knew I wasn't squatting in Mr Pendleton's former home. They were in effect convinced, emotionally at least, that I was. Impasse. I refused further co-operation and referred them back to the police.
As it happened there was a happy ending. People don't think straight under stress. As my visitors fumed on my doorstep, thinking through their next step, it occurred to me ask the obvious question, the one that should been asked at our first meeting: what did this Pendleton geezer look like. The sister described him and I recognized him at once: a shy, slightly confused, uncommunicative middle-aged man who had been a near neighbour until a few months previously. I pointed out where he had lived. Their key fitted and letters addressed to him were found behind the door.
My awkward visitors departed. They were embarrassed by the confrontational incident to the extent that a month or so later I received a written apology through the post. On balance, had the authorities actually become involved, I believe this particular matter would have been resolved correctly and quickly. But it makes you wonder. Circumstantial evidence has a powerful momentum and co-incidence has low credibility as a witness. Improbable may well not be the same as impossible, but if the odds are reasonably long, it's a very attractive first approximation.
* White Hunter was a TV serial made in the late 1950s and broadcast late at night on ITV. As well as giving us the catchphrase "true stories that actually happened" which actually did occur, breathlessly, in the titles voice-over, this splendidly hammy show was generally referred to in our house as "Throw another stuffed lion in". In the titles, the eponymous white hunter raises his rifle and fires. We then cut to a shot of what is either a loose-stuffed lion skin or quite possibly, in those less fastidious days, an actual freshly dead male lion, which is hurled into camera. Innocent days.
this blog with the inspired musings of Flann O'Brien. Well done, sir.
They do it with such practiced ease, too. On almost, it seems, any subject known to man. The worst of it is, Joe Public has an alarming tendency to believe them.
Cue...stunned looks all round,
a tumbleweed rolls past...
a bell tolls in the distance.