He'll start off reasonably straight towards the posts. But very soon he'll veer a little. And having sensed that he's veered a little he will try to correct. And in trying to correct he will veer a lot. And having veered a lot, he can go anywhere. Some start walking round in circles. Some end up behind the place they started at. Some you have to dash after and seize before they walk into a ditch or across a road.
When you remove the blindfold your victim will be astonished where he's got to. "But," he'll say, "but … " then words will fail him. Because he has just learned that he, the bold male exemplar of independence and free will, can't walk in a straight line.
The main point of the exercise, of course, is the humiliation. And the second point is the 20 bucks. (And whatever you do, don't allow sympathy to let him off the debt. He'll only learn if he pays - though probably not even then. Male vanity is durable and self-repairing.)
But the exercise also serves to remind us that for all the self-delusions of technology we remain part of nature. And in nature there are no straight lines. Straight lines are a human invention, a fiction we've devised to help us get a mental handle on the limitless complexity of the world.
I was out around dawn this morning with the dog. I wore gumboots, a coat and a beanie. The dog wore exactly what he wears every day of the year. We crossed the frosted recreation ground then walked a while along the wharf, my hands plunged deep in my pockets, the dog's nose tight to the ground, intoxicated as ever by the olfactory adventure.
When we got back to the rec some 15 minutes later there in the frost were the tracks we'd made earlier, a necklace of black smudges. Now, if you'd asked me before I saw them I'd have said that I had marched across that recreation ground in a line as straight as George Clooney.
I was wide awake, more sober than any judge I've met - though that says less than you might think - and I knew where I was heading. Yet the tracks told a different and incontrovertible truth. I had meandered. I had drifted to the right then corrected myself. I had drifted to the left then corrected myself. A neutral observer of those footmarks would have guessed I'd been perhaps six pints to the good.
As for the dog, a dozen pints. His tracks were as distinct as mine but five times as errant. But of course that does not surprise us. We expect dogs to go where they go, to be distracted by distractions. The world pulls the poor little weak-willed beasts about. But not us. We have free will. We are separate from the world, are self-steering, self-guided, independent and decisive.
Well ha. The tracks tell the truth. We are as errant as any other organism, as arbitrary and unconscious in our movements as a starfish, say, or a cabbage white butterfly.
And should we be ashamed of our erring? Should we blush at our failure to walk straight? Not a bit of it. It's who and what we are. But don't take my word for it. Here's Robert Graves, as wise a man as ever put pen to paper.
The butterfly, a cabbage white,
(His honest idiocy of flight)
Will never now, it is too late,
Master the art of flying straight,
Yet has - who knows so well as I? -
A just sense of how not to fly:
He lurches here and here by guess
And God and hope and hopelessness.
Even the aerobatic swift
Has not his flying-crooked gift.