Life is but a dream?

[sawyl]

The problem that the world that we perceive around us might only be the product of our dreaming mind has long history. Descartes takes it on in the first of his Meditations and dismisses it on the grounds that the sort of things we see in dreams are nothing but echoes:

Now let us assume that we are asleep and that all these particulars, e.g. that we open our eyes, shake our head, extend our hands, and so on, are but false delusions; and let us reflect that possibly neither our hands nor our whole body are such as they appear to us to be. At the same time we must at least confess that the things which are represented to us in sleep are like painted representation which can only have been formed as the counterparts of something real and true, and that in this way those general things at least, i.e. eyes, a head, hands, and a whole body, are not imaginary things, but things really existent.

Descartes, R., "Meditation I" in Haldane, E.S., and G.R.T Ross, trans., (1931), The Philosophical Works of Descartes, Volume 1, Cambridge University Press

I recently read about — but damn me if I can find the reference — an interesting method for differentiating between dream and reality. Essentially, the trick involves finding a piece of text, looking at it, looking away and then looking back and checking for consistency. The idea is that because of the way the dreaming mind works, it is extremely hard for it to maintain the same words coherently over time. I wish I knew where this idea came from and whether it's true, because the more I think about it, the more I come to think that it's probably something I've dreamt up from nowhere!

But my favourite form of oneiric epistemology comes from Stanisław Lem's Solaris.

When Kris Kelvin first arrives on the Solaris orbital station, he finds the situation so bizarre that he worries that he's still asleep in his ship and is dreaming the whole thing. In order to test his hypothesis, he comes up with a plan that involves observing a remote satellite that generates a complex but ultimately predicable signal. He uses the station's instruments to obtain a value from the satellite, before going through a series of manual calculations to determine the correct answer. He then compares the two to see if they match.

Obviously, if he is dreaming the whole station, the observation taken with the station's instruments would have been generated by his unconscious — as would be the case for the station's computers, which is why the calculation has to be carried out manually. Since the task of generating a correct value for the observation is computationally intensive, any dream generated value must fail to match the computed value. So, if the two do match, as they do in the novel, the contradictory applies and Kelvin is forced to accept that the peculiarities of the station are not completely the manifestation of his unconscious mind.

As an idea, I love it: it has elegance, it's neatly logical and it's in the grand tradition of bootstrapping an episemetic system system using synthetic, i.e. necessary, truths. On the other hand, my dyslexia means that I find certain mathematical tasks — particularly arithmetic and some forms of algebra — nightmarishly hard so, were I to find myself in Kelvin's situation, I'd probably struggle through the maths only to come out with the wrong final value and wrongly conclude that I was indeed living in a dream. So perhaps I'd be better off sticking to my half-imagined text test...