Last revised 9 May 2021
"[The Red King is] dreaming now," said Tweedledee: "and what do you think he's dreaming about?"
Alice said: "Nobody can guess that."
"Why, about you! Tweedledee exclaimed, clapping his hands triumphantly. "And if he left off dreaming about you, where do you suppose you'd be?"
"Where I am now, of course," said Alice.
"Not you!" Tweedledee retorted contemptuously. "You'd be nowhere. Why, you're only a sort of thing in his dream!"
"If that there King was to wake," added Tweedledum, "you'd go out—bang!—just like a candle!"
"I shouldn't!" Alice exclaimed indignantly. "Besides, if I'm only a sort of thing in his dream, what are you, I should like to know?"
"Ditto", said Tweedledum.
"Ditto ditto," cried Tweedledee.
He shouted this so loud that Alice couldn't help saying, "Hush! You'll be waking him, I'm afraid, if you make so much noise."
"Well, it's no use your talking about waking him," said Tweedledee, "when you're only one of the things in his dream. You know very well you're not real."
"I am real!" said Alice, and began to cry.
"You won't make yourself a bit realler by crying," Tweedledee remarked: "there's nothing to cry about."
"If I wasn't real," Alice said—half-laughing through her tears, it all seemed so ridiculous—"I shouldn't be able to cry."
"I hope you don't suppose those are real tears?" Tweedledum interrupted in a tone of great contempt.
[Lewis Carroll: Through the Looking-Glass]
Such ideas find their modern technological counterpart in the simulation hypothesis, which proposes that the whole of reality—the entire universe—is an computer simulation.
Who is thought to be responsible for the simulation? The usual answer is: our own remote descendants, who are supposed to have taken computing power far beyond what exists today. It's equally conceivable that the simulators could be non-human beings on other planets, in other galaxies, or even in other universes.
There doesn't seem to be an obvious way of testing the simulation hypothesis, but is there any positive reason to believe that it might be true? I think there may be.
In the nineteenth century a group of British intellectuals came together and founded the Society for Psychical Research (SPR) to study such phenomena; the American Society for Psychical Research soon followed (the philosopher and psychologist William James was a prominent member).4 These organisations still exist although they attract less attention than they did in earlier times; sceptics generally reject the paranormal out-of-hand, as due to superstition, fraud, or misreporting. But not all scientists are so dismissive; for example, Bernard Carr, professor of mathematics and astronomy at Queen Mary University of London, is a past President of the SPR.5
A particularly good example of a hard-to-explain anomaly of this kind is the poltergeist phenomenon. Currently BBC Radio 4 is providing a dramatised account of a fairly recent case, The Battersea Poltergeist. For an extensive academic treatment of the topic, see the book by Alan Gauld and A.D. Cornell.6. The cases they describe seeem impossible to explain in any rational manner, yet there is no reason to reject them except their intrinsic incredibility. But is that enough? Gauld and Cormell are critical thinkers and have a lot of first-hand experience of the matter while I have none. I therefore have to keep an open mind about it, but if they are right, the world must be a much stranger place than we rationalists like to think it is. Books like this,I find, induce in me a state of uncomfortable cognitive dissonance,
The main reason why most sceptics ignore studies like that of Gauld and Cornell is simply that the alleged phenomena are inexplicable in a scientifically based world view. They don't make sense. But if the simujlation hypothesis is true, this difficulty disappears. The phenomena have been inserted by the simulators for reasons of their own.. This solves the problem; it allows us to accept the reports of strange phenomena at face value without compromising our scientific rationality. But at a price, of course; we have to accept that we are computer avatars, creatures in someone else's dream.