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Is this the real life or just fantasy?
December 2018 / January 2019

“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.
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