Top scientist asks: is life all just a dream?

DEEP THOUGHT, the supercomputer created by novelist Douglas Adams, got there first, but now the astronomer royal has caught up. Professor Sir Martin Rees is to suggest that “life, the universe and everything” may be no more than a giant computer simulation with humans reduced to bits of software.

Rees, Royal Society professor of astronomy at Cambridge University, will say that it is now possible to conceive of computers so powerful that they could build an entire virtual universe.

The possibility that what we see around us may not actually exist has been raised by philosophers many times dating back to the ancient Greeks and appears repeatedly in science fiction.

That’s a dodgy report, to say the very least. Certainly, it trivialises the ideas of Descartes and Russell, and uses false analogies in citing The Hitchhiker’s Guide to the Galaxy, The Matrix and Vanilla Sky as supposedly demonstrative that the idea of the universe being a simulation still fascinates. In none of these works is it suggested that humans are themselves in any important sense contingent simulations, i.e. ones without any real autonomy, which is what Rees seems to be proposing. If so, those analogies are essentially flawed.

In any case, here’s a test procedure that aims to gauge the validity and/or the significance of the simulation hypothesis that everyone can try and then draw therefrom their own conclusions:
[ol]- Remove shoe and sock from right foot (or left foot if left-handed);- Select football-sized rock about 20 metres away;- Run with maximum speed at selected rock;- At the correct moment, kick selected rock as hard as possible, and- After a suitable recovery period, assess the outcome against the assumption of it all being simulated.[/ol]

If the conclusion is anything other than a resounding, “Thus, I refute you!” the experimenter should ask a loved one to repeat the experiment.


But the rock and the foot and the experience of pain are all simulated. I don’t get that that experiment refutes anything, iconic though it is.

I was thinking about this recently while reading A Beginner’s Guide to Reality. A problem with arguments against reality being simulated is that since we only have our experience (including the experience of the fact that we think), nothing stops it being simulated. Baggott’s conclusion is that you can’t really be sure, and my conclusion is it doesn’t really matter. If everything important about my life is simulated, that doesn’t stop it being important - although a lot of the arguments about this suggest that many people don’t share this view. :-\

If by real autonomy you mean shudder free will … hey, I can simulate that too. I can give you the impression of having made free decisions that serve your interests and not anyone else’s, certainly not ‘fate’ or some higher being. Players of The Sims don’t dictate their every move, after all.

What interests me more is to speculate on the nature of who’s doing the simulation. And why they would create a universe and a world like this. They must be into pain and meaningless suffering. And vast empty spaces between stars. In other words, if it’s simulated and directed, and intentionally this way, many of the questions about pain and evil in theology arise.

I think of the simulator(s) as nerdy role-playing gamers and programmers. And that’s not a comforting thought, Frodo. :wink:

In a weak sense, the totality of our experiences of the world in any case consists of simulations since the world comes to us filtered through our senses and an assortment of synaptic processes.

The experiment is not so much meant to decide the actuality as it is meant to decide the practicality of the nature of our experiences of the world.

A big part of the problem is, of course, that the nature of consciousness is almost entirely obscure. The experiment requires that something is doing the actual experiencing, be it you or the agent of simulation. In either case, there’s an awareness of the experience and, in addition, an awareness of that awareness, i.e. “I know that I am experiencing this,” or self-awareness. Now I think we can agree that, no other options being evident, either the experience is pretty much genuine as perceived, or it is simulated in toto because anything less would leave detectable traces of some kind, such as us not wondering about this question at all. But this requirement means that, in the case of a simulation, the aforementioned succession and hierarchy of awarenesses must itself be simulated, leaving again two options: (1) the simulation is self-aware (which, it may be noted, includes the case where such awareness stems from the simulator), or (2) there’s a succession of simulations, each one chasing another’s tail to provide the illusion of self-awareness.

Option (2) is wholly unsatisfying because it relies on either a circular set or on an infinite regress of simulations, and in any event still fails to provide a satisfactory account of self-awareness, encumbering it, as it does, with contrived complexity. With option (1) it clearly doesn’t matter whether it’s all genuine or a completely self-aware simulation because these two possibilities are, from our individual or collective vantage, in no way distinguishable from each other, and the question becomes just as unanswerable and ultimately pointless as wondering whether we and the world were created, hale and intact in all respects, six seconds ago.

These are the things the experiment is meant to address.


Good points again. But I’m at a loss to see how the foot-rock experiment addresses option (1). And option (2) falls apart by itself, by your infinite regress point. Option 2 is essentially the “brain in a vat” scenario. But if everything we experience is simulated, we have no evidence to discuss brains and vats so the assumed “real” reality of the brain in a real vat in some real mad scientist’s castle has no basis. There would be no conclusions we could draw about it … unless some part of our experience is direct, which I think is what you were getting at with your “detectable traces” point.


Here my skepticism kicks in, especially given your previous sentence. We need to be cautious. Experiences happen, but it’s not at all obvious to me that we can conclude there is something doing the experiencing.

I believe the existence of experiences is enough to create to impression that “I” am something distinct from the thing being experienced, but there’s no real necessity for this. Consider a character in The Sims 3 (an imagined future release), where a Sim can talk back to you and report their experiences using the word “I”. This can and will be programmed. But it won’t create a new entity of a different order from a database table.

… I seem to be refuting “I think, therefore I exist.” Hmm.


Plus Occam’s Razor. Okay now?

That’s akin to saying that, assuming it to be a simulation, it’s not at all obvious that there’s something doing the simulating. How can experience and an awareness of it (with the attendant subjectivity this entails) each exist in independent and separable vacuums while still retaining their essential characters? My point here is that since you know when you are experiencing something (i.e. you are self-aware), quite apart from the perceived content of the experience, and since this knowledge is only objective to the extent that it is about your relationship to the experience, you will be left with a meta-experience, a meta-meta-experience, a meta-meta-meta-… (you get the drift) that a simulation doesn’t adequately account for, unless you define experience simply as a series of events absent any subjective appraisal, which is merely a semantic trick. But clearly experiences do have such a subjective element (if they didn’t, the question posed in this thread would either not have arisen at all or it wouldn’t be hard to answer).

Simultaneously and just as importantly, it is not at all clear that consciousness and self-awareness are algorithmic, which needs to be shown if it is contended that we and our experiences are simulated.

You’re begging the question here: paraphrased this says, “my own experiences cause me to believe myself separable, and therefore I am able to distinguish between myself and my experiences.”

Although a Sims 3 character may outwardly exhibit a wide range of (abstract) attributes, it is hard to see how consciousness or self-awareness is to be counted among them. Are you familiar with the Turing Test and criticisms of it? It is far easier to see that the facets of intelligence (ability to assimilate new information, pattern matching, logical reasoning) measured by the Turing Test conceivably are algorithmic than that those of consciousness should be so, and no equivalent test exists in this latter context. Yet we as humans recognise it without much difficulty, and the concomitant objection that algorithmic sophistication is not sufficient still remains largely unaddressed.