Tuesday, January 21, 2014

Stanislaw Lem's Proof that the External World Exists

Slowly catching up on science fiction classics, reading Lem's Solaris, I'm struck by how the narrator, Kris, escapes a skeptical quandary. Worried that his sensory experiences might be completely delusional, Kris concocts the following empirical test:

I instructed the satellite to give me the figure of the galactic meridians it was traversing at 22-second intervals while orbiting Solaris, and I specified an answer to five decimal points.

Then I sat and waited for the reply. Ten minutes later, it arrived. I tore off the strip of freshly printed paper and hid it in a drawer, taking care not to look at it.... Then I sat down to work out for myself the answer to the question I had posed. For an hour or more, I integrated the equations....

If the figures obtained from the satellite were simply the product of my deranged mind, they could not possibly coincide with [my hand calculations]. My brain might be unhinged, but it could not conceivably complete with the Station's giant computer and secretly perform calculations requiring several months' work. Therefore if the figures corresponded, it would follow that the Station's computer really existed, that I had really used it, and that I was not delirious (1961/1970, p. 50-51).

Except in detail, Kris's test closely resembles an experiment Alan Moore and I have used in our attempt to empirically establish the existence of the external world (full paper in draft here).

Kris is hasty in concluding from this experiment that he must have used an actually existing computer. Kris might, for example, have been victim of a deceiver with great computational powers, who can give him the meridians within ten minutes of his asking. And Kris would have done better, I think, to have looked at the readout before having done his own calculations. By not looking until the end, he leaves open the possibility that he delusively creates the figures supposedly from the satellite only after he has derived the correct answers himself. Assuming he can trust his memory and arithmetical abilities for at least a short duration (and if not, he's really screwed), Kris should look at the satellite's figures first, holding them steady before his mind, while he confirms by hand that the numbers make mathematical sense.

Increasingly, I think the greatest science fiction writers are also philosophers. Exploring the limits of technological possibility inevitably involves confronting the central issues of metaphysics, epistemology, and human value.

15 comments:

Marco Devillers said...

The old science fiction was so much better than hey-you've-got-a-primitive-brain crap they produce these days.

Marco Devillers said...

I glanced at your anti-solipsist paper.

You do a number of experiments. But I would expect the argument against solipsism to be a default "other entities provide you with thoughts you cannot conceive yourself" kind-of argument.

This must be there in literature. Why do radical solipsists reject the argument?

Matt B2 said...

How do you know that the synchronized events of your life are not caused by your mind reordering events? Because good is dumb.

Brandon N. Towl said...

Doesn't Dennett make a very similar move in Consciousness Explained?

Eric Schwitzgebel said...

Hi Marco --

There's some pretty philosophical newer stuff too, e.g., Greg Egan, Ted Chiang.

That's not a bad one-liner summary of Alan's and my paper. I haven't seen a really good presentation of that argument in the literature. Russell makes a passing remark, and maybe Jonathan Vogel includes it among the things best explained by the real world hypothesis (I'd have to check). There's Decartes's attempt, which involves assuming that certain ideas could only come from a perfect God. Possibly it's an important part of what's going on in Hegel, but I find Hegel difficult to interpret. If you find a good source, fill me in! I share your sense that Alan and I might be missing something obvious.

Eric Schwitzgebel said...

Brandon: Dennett's argument near the beginning of Consciousness Explained is pretty different, though related. It doesn't involve, for example, a risky specific prediction. And I think it's not entirely clear that the trickster parts of brain couldn't create enough regularity to fool the parts consuming the tricks -- especially in light of Dennett's own remarks later about how we construct regularity in our experiences sometimes from pretty thin input.

Eric Schwitzgebel said...

Matt B2: Alan and I bracket that concern for the purposes of our paper. Can't do everything at once! I'd be interested to hear if you have a proposed test.

Callan S. said...

But if he looks at the results, then he could simply be making stuff that fits the results?

What of simply running it both ways?

Eric Schwitzgebel said...

Callan -- not without making mathematical errors that he should catch unless he yields to skepticism about his mathematical reasoning. At least, that was Alan's and my thinking in setting up our version in the way we did.

Michel Clasquin-Johnson said...

"... unless he yields to skepticism about his mathematical reasoning"

mmm, yes, and why not? why should experience of the external world be totally open to doubt, but experience of the inner world be regarded as inviolate? Do dualism, much?

A malevolent entity that is capable of making me doubt that I have really consulted a computer aboard a satellite should be equally capable of making me think that 1 + 1 = 3

Eric Schwitzgebel said...

Michel: I prefer not to doubt such things, because then there is no way back! (No way other than Hume's backgammon cure, that is.) But I do think there is a way back if one simply doubts that the external world exists, while granting fairly modest assumptions about your reasoning and memory.

Callan S. said...

Eric, I had thought the story very specific about the matter of not looking, so as to avoid confirmation bias?

If he's left to catching his own math mistakes, that's leaving it at an internal interaction in order to determine the existance of the external, isn't it?

howard berman said...

Is the brain part of the outside to the mind? Would that play into this thought experiment?

Eric Schwitzgebel said...

Howard: In Alan's and my version, we assume that any nonconscious part of the mind is "external" in the relevant sense, and we don't assume that the brain exists.

MJ said...

You might be interested in Peter Swirski's short book "Of Literature and Knowledge: Explorations in Narrative, Thought Experiments, Evolution, and Game Theory".

Swirski discusses Lem a bit in that book, but more extensively in other writings - he is apparently the foremost scholar on Lem.