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External Coherence and the Reality of The Matrix

David Chalmers writes:

I think that even if I am in a matrix [i.e. any computer simulation similar to the one depicted in The Matrix], my world is perfectly real. A brain in a vat is not massively deluded (at least if it has always been in a vat) ... Philosophers have held this sort of view before. The 18th-century Irish philosopher George Berkeley held, in effect, that appearance is reality ... If this is right, then the world perceived by envatted beings is perfectly real: they have all the right appearances and appearance is reality ("The Matrix as Metaphysics" in Susan Schneider, ed., Science Fiction and Philosophy: From Time Travel to Superintelligence, p. 35; online version here).

This, however, gets Berkeley wrong. To see why, let us first consider what Berkeley says about dreams (the issue which happens to have been my first introduction to Berkeley studies):

HYLAS. But according to your notions what difference is there between real things, and chimeras formed by the imagination, or the visions of a dream, since they are all equally in the mind?
PHILONOUS. The ideas formed by the imagination are faint and indistinct; they have besides an entire dependence on the will. But the ideas perceived by sense, that is, real things, are more vivid and clear, and being imprinted on the mind by a spirit distinct from us, have not a like dependence on our will. There is therefore no danger of confounding these with the foregoing: and there is as little of confounding them with the visions of a dream, which are dim, irregular, and confused. And though they should happen to be never so lively and natural, yet by their not being connected, and of a piece with the preceding and subsequent transactions of our lives, they might easily be distinguished from realities. In short, by whatever method you distinguish things from chimeras on your own scheme, the same, it is evidence, will hold also upon mine. For it must be, I presume, by some perceived difference, and I am not for depriving you of any one thing that you perceive. (Dialogues 235)

What Chalmers is right about is that, for Berkeley, whether our perceptions correspond to some metaphysically fundamental material substratum has nothing to do with whether the world we live in is "real." This is good news, since 'material substratum' is conceptually incoherent. However, Berkeley still claims that we can distinguish between veridical perceptions (like those we usually have when awake) and non-veridical perceptions (like those we usually have when dreaming). One of the ways that we can distinguish between them is by external coherence - that is, whether they fit together with the rest of our experiences to form a coherent life narrative. Dreams typically don't fit into this narrative. In this way, dreams are like the famous straight oar:

HYLAS. What say you to this? Since, according to you, men judge of the reality of things by their senses, how can a man be mistaken in thinking the moon a plain lucid surface, about a foot in diameter; or a square tower, seen at a distance, round; or an oar, with one end in the water, crooked?
PHILONOUS. He is not mistaken with regard to the ideas he actually perceives; but in the inferences he makes from his present perceptions. Thus in the case of the oar, what he immediately perceives by sight is certainly crooked; and so far he is in the right. But if he thence conclude, that upon taking the oar out of the water he shall perceive the same crookedness, or that it would affect his touch, as crooked things are wont to do, in that he is mistaken ... his mistake lies not in what he perceives immediately and at present (it being a manifest contradiction to suppose he should err in respect to that) but in the wrong judgment he makes concerning the ideas he apprehends to be connected with those immediately perceived; or concerning the ideas that, from what he perceives at present, he imagines would be perceived in other circumstances. (Dialogues 238)

One can never be mistaken about, for instance, perceiving a purple dragon (or, at least, one can't be mistaken about seeing a purple dragon-shape on one's field of vision). So a dreamer who sees a purple dragon is not mistaken about his visual sensations ("it being a manifest contradiction that he should err in respect to that"). However, he may be mistaken in supposing that the purple dragon will, together with his other experiences, form a coherent life narrative.

This is precisely Neo's situation before leaving the Matrix: he has a variety of perceptions, and he judges rightly that he has these perceptions, but is radically deceived with respect to the role he expects these perceptions to play in the rest of his life experiences. As it turns out, it is possible to 'unplug,' and one's unplugged experiences do not bear at all the expected relationship to one's plugged in experiences. This does have one consequence that looks like the one Chalmers wants to foist on Berkeley: if it were impossible to unplug, Neo would not be radically deceived. However, the actual facts in the film are such that Neo is radically deceived, and the same is true of any 'envatted' individual with the possibility of escape.

Posted by Kenny at August 24, 2009 4:50 PM