Neo has woken up from a hell of a dream — the dream that was his life. How was he to know? The cliché is that if you are dreaming and you pinch yourself, you will wake up. Unfortunately, things aren't quite that simple. It is the nature of most dreams that we take them for reality — while dreaming we are unaware that we are in fact in a dreamworld. Of course, we eventually wake up, and when we do we realize that our experience was all in our mind. Neo's predicament makes one wonder, though: how can any of us be sure that we have ever genuinely woken up? Perhaps, like Neo prior to his downing the red pill, our dreams thus far have in fact been dreams within a dream.

The idea that what we take to be the real world could all be just a dream is familiar to many students of philosophy, poetry, and literature. Most of us, at one time or another, have been struck with the thought that we might mistake a dream for reality, or reality for a dream. Arguably the most famous exponent of this worry in the Western philosophical tradition is the seventeenth-century French philosopher Rene Descartes. In an attempt to provide a firm foundation for knowledge, he began his Meditations by clearing the philosophical ground through doubting all that could be doubted. This was done, in part, in order to determine if anything that could count as certain knowledge could survive such rigorous and systematic skepticism. Descartes takes the first step towards this goal by raising (through his fictional narrator) the possibility that we might be dreaming:

"How often, asleep at night, am I convinced of just such familiar events — that I am here in my dressing gown, sitting by the fire —when in fact I am lying undressed in bed! Yet at the moment my eyes are certainly wide awake when I look at this piece of paper; I shake my head and it is not asleep; as I stretch out and feel my hand I do so deliberately, and I know what I am doing. All this would not happen with such distinctness to someone asleep. Indeed! As if I did not remember other occasions when I have been tricked by exactly similar thoughts while asleep! As I think about this more carefully, I see plainly that there are never any sure signs by means of which being awake can be distinguished from being asleep. The result is that I begin to feel dazed, and this very feeling only reinforces the notion that I may be asleep." (Meditations, 13)

When we dream we are often blissfully ignorant that we are dreaming. Given this, and the fact that dreams often seem as vivid and "realistic" as real life, how can you rule out the possibility that you might be dreaming even now, as you sit at your computer and read this? This is the kind of perplexing thought Descartes forces us to confront. It seems we have no justification for the belief that we are not dreaming. If so, then it seems we similarly have no justification in thinking that the world we experience is the real world. Indeed, it becomes questionable whether we are justified in thinking that any of our beliefs are true.

The narrator of Descartes' Meditations worries about this, but he ultimately maintains that the possibility that one might be dreaming cannot by itself cast doubt on all we think we know; he points out that even if all our sensory experience is but a dream, we can still conclude that we have some knowledge of the nature of reality. Just as a painter cannot create ex nihilo but must rely on pigments with which to create her image, certain elements of our thought must exist prior to our imaginings. Among the items of knowledge that Descartes thought survived dream skepticism are truths arrived at through the use of reason, such as the truths of mathematics: "For whether I am awake or asleep, two and three added together are five, and a square has no more than four sides." (14)

While such an insight offers little comfort to someone wondering whether the people and objects she confronts are genuine, it served Descartes' larger philosophical project: he sought, among other things, to provide a foundation for knowledge in which truths arrived at through reason are given priority over knowledge gained from the senses. (This bias shouldn't surprise those who remember that Descartes was a brilliant mathematician in addition to being a philosopher.) Descartes was not himself a skeptic — he employs this skeptical argument so as to help remind the reader that the truths of mathematics (and other truths of reason) are on firmer ground than the data provided to us by our senses.

Despite the fact that Descartes' ultimate goal was to demonstrate how genuine knowledge is possible, he proceeds in The Meditations to utilize a much more radical skeptical argument, one that casts doubt on even his beloved mathematical truths. In the next section we will see that, many years before the Wachowskis dreamed up The Matrix, Descartes had imagined an equally terrifying possibility.

Further Reading:

Dancy, Jonathan. Introduction to Contemporary Epistemology, Blackwell, 1985.

Descartes.The Philosophical Writings of Descartes, tr: John Cottingham, Robert Stoothoff, Dugald Murdoch. Cambridge University Press, 1984

Stroud, Barry.The Significance of Philosophical Scepticism, Oxford, 1984.