A confession (although my regular readers will likely be unsurprised): For me, many of the most perplexing philosophical problems relate to philosophers themselves. Here’s one thing I mean by that. I find the arguments for sense-data unmoving–they are few in number and they radiate only a meager glory. But I find the fact that philosophers have come to believe (in some at least professional sense of that term) that there are sense-data deeply fascinating. How can that be? It staggers credulity. Surely no one, not Russell, not Moore, especially not Moore, really believes that there are sense-data?
When you look closely at supposed arguments for sense-data, you actually find little argumentation. Conjuration is what you find instead. Sense-data are made to appear (usually hands are waved, even while they are perhaps waived) via an open sesame–‘illusion’, ‘dream’, ‘error’, ‘double-vision”, ‘after-image’.
In his “Moore’s Theory of Sense-Data”, O. K. Bouwsma masterfully reveals how hard it is to succeed–or, how easy it is to fail–to get the conjuration right. Moore takes himself to have supplied instructions that will allow the reader to “pick out” a sense-datum. (Look at your hand and do as follows….) Bouwsma tries repeatedly to follow Moore’s instructions, but never manages to pick out a sense-datum–he keeps slipping, seeing his hand and failing to see the sense-datum. Bouwsma ends the essay by noting that he has not refuted Moore: and that is surely right. But we should also remember that a set of instructions is neither valid nor sound. It is either helpful or not. Bouwmsa has shown that Moore’s instructions are not helpful. They didn’t help Moore. Moore took himself to have picked out a sense-datum (he seems to have had one handy) and then asked himself how he had gone about it, assuming, we might say, that since he had succeeded (however he did, if he did), anyone following his instructions would succeed. Moore as reverse-engineer. How much help are Moore’s instructions for someone who does not (yet) believe in sense-data and is waiting for one to appear, waiting to succeed in picking one out, before believing in them? (I’m from Missouri; show me!)