It may not be possible to know if we are living in a simulation — but perhaps we don’t need certainty
Creating the illusion of life: The Mechanical Turk, above, actually contained a well-hidden human chess master
Towards the end of the Second World War, when physicists in America were working on the Manhattan Project, they used computer simulation to model the process of nuclear detonation. Now simulations are everywhere, from astrophysics to climatology, economics to healthcare, and as computers get ever more powerful there is talk of simulating parts of the universe itself. Some philosophers even ask whether our own universe might not be a simulation, and as one journalist wrote in the New York Times some years ago:
Until I talked to Nick Bostrom, a philosopher at Oxford University, it never occurred to me that our universe might be somebody else’s hobby. But now it seems quite possible. In fact, if you accept a pretty reasonable assumption of Dr Bostrom’s, it is almost a mathematical certainty that we are living in someone else’s computer simulation.
The argument for “certainty” is statistical, like the belief in other intelligent life, and the argument for simulation is partly driven by our loose understanding of quantum theory. Indeed, as the physicist Richard Feynman said, “If you think you understand quantum mechanics, you don’t understand quantum mechanics.” But computer simulation, based on current technology, is no answer, though the question of how our world came into being is a good one.
In the Babylonian creation myth, the Enuma Elish, it arose from a watery monster, replicated in the Hebrew Bible as “the deep”. The monster was slain, earth and the firmament formed from her body, and the clay of the earth mixed with the blood of a sacrificial god to form humans. The Hebrew Bible takes a more abstract view, its six days of creation ending with God creating humans, after which Adam names the animals, in Hebrew of course. Even at the end of the 19th century, when cuneiform tablets were being read and deciphered, one scholar insisted that the writing on early tablets from Uruk must be a form of code because it wasn’t remotely related to Hebrew. Biblical fundamentalism was continuing to cause confusion, despite the findings of Darwin, but others recognised the language for what it was — Sumerian, which had died out as a spoken tongue before the lifetime of Abraham.
Meanwhile, advances in technology began to make otherwise sensible folk believe we might create life ourselves (Frankenstein), or superior mental abilities as in the Mechanical Turk, a brilliant but fake chess-playing machine in the 18th century. Now they have moved from mechanical wizardry to computers — not even quantum computers — to create the world we live in, while philosophers still grapple with the nature of reality, as they were already doing in Plato’s cave, or Descartes’ cogito, ergo sum.
Well before the advent of computer simulations the question of reality was often expressed as a philosophical puzzle about being part of someone’s dream, and whether we could tell if we were. This is expressed well in a play (as yet unstaged) by Ben Brown, The Language Game, depicting Wittgenstein, Russell, Francis Skinner, and G. E. Moore, who delivers a lecture. Drawing on Moore’s own writings, his character starts by asserting some obvious things: he is clothed, standing up and speaking, and goes on to say:
“Now I have made a number of different assertions . . . as if there were no doubt whatever that they were true . . . Many philosophers, however, believe that, on the contrary, all these assertions are in fact in doubt because I cannot be certain that I am not dreaming. Why do they believe this?
“Well, they might start by pointing out that ‘some at least of the sensory experiences which you are now having are similar in important respects to dream-images which actually have occurred in dreams.’
. . . And, indeed, this seems a very harmless premiss and I am quite willing to admit it. But note that a philosopher who uses this premiss, is actually implying, though he does not expressly say, that he himself knows that dreams have occurred. And, of course, I think he would be right. All the philosophers I have ever met or heard of know that dreams have occurred. We all know that dreams have occurred. But — and this is the crux of the matter — can he consistently combine this proposition that he knows that dreams have occurred, with his conclusion that he does not know that he is not dreaming? Can anybody possibly know that dreams have occurred, if, at the time, he does not know that he is not dreaming? If he is dreaming, it may be that he is only dreaming that dreams have occurred — and if he does not know that he is not dreaming, can he possibly know that he is not only dreaming that dreams have occurred? Can he possibly know therefore that dreams have occurred?”
He takes a sip of water, and continues,
“I do not think that he can, and therefore I think that anyone who uses this premiss and also asserts the conclusion that nobody ever knows that he is not dreaming, is guilty of an inconsistency.”
Inconsistency is a perennial danger, and so is certainty where even in the crystal- clear waters of mathematics it took a beating with Gödel’s Incompleteness Theorems. Within a perfectly consistent set of axioms there can be statements that cannot be proved — within that system. Perhaps the universe is like that. However much we find out and understand, there will always be more. We cannot know whether we are part of a simulation, but is it relevant? The purpose of physics is to extend our knowledge, even though we will never know the end of it. I leave (almost) the last word to St Augustine:
If God’s power ever ceased to govern creatures their essences would pass away and all nature would perish. When a builder puts up a house and departs, his work remains in spite of the fact that he is no longer there. But the universe will pass away in the twinkling of an eye if God withdraws his ruling hand.
If the power running a simulation is withdrawn then everything vanishes, and like the actors in The Tempest, we are “all spirits and are melted into air, into thin air: and, like the baseless fabric of this vision . . . shall dissolve . . .[and] leave not a rack behind. We are such stuff as dreams are made on . . .” Dreams, simulations and reality: yet our job is to live on, understand as much as we can, and pass the baton.