There's Nothing About Mary

Brian Weatherson posted the other day on the puzzlingly puzzling case of Mary the Color Scientist. (Brian analyzes the problem from the standpoint of defeasible knowledge. As always, he says some interesting things, but I'm not posting here to assess his argument.) 

I say puzzlingly puzzling because in my mind I can't imagine why Frank Jackson's hoary hypothetical is still considered a puzzle in the philosophy of mind.

The key, and very simple-to-understand, observation is this: Ambiguous talk of "knowledge" aside, there is no reason to suppose that the process of looking at color stimuli will induce the same brain state as looking at sentences about the process of looking at color stimuli. If anything, intuitions should run the other way.

Consider the case of MARy (which stands for Machine-based Algorithmic Robiomimicry) the Computer. MARy is endowed with sophisticated visual processing software that includes a discrete, heuristic color processing component and a discrete OCR component [/suitably technical-sounding gobbledygook], the upshot of which is that MARy's language-processing capabilities allow her lab mates to enter natural language queries about her visual "experiences" and receive appropriately detailed (and reasonably accurate) responses.

Now look at two scenarios, each of which for MARy is an alternative "first encounter" with a red-colored stimulus:

1. MARy is shown a red card.
2. MARy is shown the text of an appropriately detailed physical description of what would happen within MARy were MARy shown a red card.

Obviously, Jackson's argument can only be applied to MARy's "knowledge" about the color red if one assumes the procedures described in (1) and (2) elicit--or rather, are supposed to elicit--identical (in the relevant respects) physical states within MARy.

But it is plain that such an assumption is totally unmotivated by physicalism--or any other ontology, for that matter. Indeed, that assumption is almost certainly counterintuitive to anyone with even a smattering of knowledge about computers. (If you ever meet someone who thinks you can make iTunes play "Baba O'Riley" by typing source code into Word, let me know.)

An analogous argument holds with respect to neural states in the brain.

In sum, then, ambiguous talk of "knowledge" aside, there is no reason to suppose that the process of looking at color stimuli will induce the same brain state as looking at *sentences about* the process of looking at color stimuli.

(Note that this is argument is independent of, say, Ryle's distinction between knowing-how and knowing-that, bypassing ambiguous talk about "knowledge" altogether in favor of an analysis in terms of informational enrichment.)