I will conclude with a discussion of the non-revisability of our world-picture. We have seen that eliminative materialists believe that our ordinary ways of characterizing human mental life are deeply mistaken; that nothing science is likely to discover in its investigation of what they call the mind-brain will correspond to the supposedly felt experiences and sensations that plain men call "beliefs", "thoughts", "intentions", and "desires". If this should turn out to be the case, they predict that these terms may well be dropped from our folk-psychological vocabulary. Further, they argue that because these notions are part of our common sense framework, such changes would amount to a massive revision of that framework. Suppose that, contrary to what both Wittgenstein and I claim, this should happen; that the whole range of psychological terms should disappear from everyday discourse. Would that affect Wittgenstein's claim that our common sense system of beliefs -- our world-picture -- is not revisable? The answer is that it would not.
As I pointed out earlier, in speaking of beliefs Wittgenstein is not speaking of mental functions in the sense of introspective felt experiences, but of certain sorts of practices or activities that are constitutive of communal life. What does he mean by this? Let us take a specific example, what he calls "the game of doubting". Suppose a friend asserts that Smith holds the record for consecutive hits in baseball. Your recollection is that it was Jones. Your recollection gives you a reason for doubting the claim. But now you set out to discover the answer. You check old newspapers, clippings in libraries, various baseball encyclopedias. These activities are what Wittgenstein means by the game of doubting. When you find the answer in a book of records the game of doubting comes to an end. You now show the answer to your friend. If he refuses to accept the report, he has resumed the game; but if he has no further grounds than his own recollection for challenging the accuracy of the report, serious doubting has stopped. The game is no longer being played according to established community rules. Your friend is now outside the language game. This is what the sceptic does when he contends that seeing is no longer a reliable criterion for believing that a chair is in the room. In that case, serious doubting has come to an end.
Now is it conceivable that even if the word "doubt" should be dropped from common usage that the practice of doubting should cease? Well, it is, of course, conceivable that all human beings might be forced to ingest a so-called "concessive drug" whose effect would be to secure universal agreement on all issues, no matter what the claim. Then in that sense we can imagine the practice of doubting to disappear. But this is not a serious conjecture nor is it comparable to what eliminative materialists are asserting. Their claim is that now, persons as we know them, are not constituted in ways that their everyday speech suggests. That is, eliminative materialists mean that present day society, as we know it, might without conceptual loss revise its vocabulary so as to eliminate such terms as "doubt" and "belief", relegating them to a dust bin that includes such other folk-concepts as "demon" and "witch". So the parallel question is whether, without any conceptual loss, we can conceive of present day society without the practice of doubting and its congeners. I submit we cannot, and will give two arguments in support of this claim.
The first of these is an argument tu quoque. It does not show that Wittgenstein is right simpliciter; what it shows is that if the eliminative materialists are right, then Wittgenstein is also right in saying that our common sense framework is not revisable. For if they are right, then it would mean that any scientist would have to play the game of doubting in order to show that there is no correlation between our supposedly felt mental states and what science discovers about the brain. Scientists would do something analogous to what you did when you challenged your friend's assertion about the record for consecutive hits. They would begin by doubting a certain thesis. They would go on to collect and assess evidence purporting to show that no brain state corresponds to any felt or introspectible mental experience. That process would be highly complex, and would involve their engaging in a number of familiar human practices. From a Wittgensteinian perspective, they would have been playing the game of doubt. Accordingly, it is evident that scientific practice is not correctly described by eliminative theory, since doubting is an essential ingredient of that practice. In effect, the eliminative materialist is hung upon his own petard for the practice of revising in science would not exist unless the practice of doubting did as well. But the latter is an inexpungible part of our common sense framework. if it is not eliminable then neither is the framework itself.
But since I have indicated that I do not think the eliminativist is right, then we need an independent argument to show that Wittgenstein is right. That argument, whose full scope cannot be developed here, holds that human communal life is to a great extent defined by a spectrum of practices, not only those about which we have been speaking, but also the practice of revising itself. What would it be like to revise that practice? Is the notion of revising the practice of revising sensible? I submit that it is not, that the endeavor would require engaging in the very practice it seeks to amend. The suggestion does not, therefore, engender a world-picture we can comprehend. Insofar as it purports to describe anything that "thing" will not be a human community, since it would lack all investigative procedures, not only those of the sciences and social sciences, but those of everyday life as well. "Such a 'revision'", Wittgenstein writes putting the word 'revision' in quotes, "would amount to the annihilation of all yardsticks". (492)
This same lack of cogency will apply to the suggestion that we can revise or eliminate such practices as doubting, judging, and affirming, and that we shall still be left with a human society. To make such claims is to assert that human society would be what it now is, and in the same breath to affirm by these essential modifications that it would not be. And this is clearly nonsensical. It would be like insisting upon playing the game we call "chess" without using the piece we call "the queen". That is the sort of impossibility that Wittgenstein is describing in On Certainty.
"Wittgenstein and Folk Psychology"
Philosophy of Law, Politics, and Society: Proceedings of the 12th International Wittgenstein Symposium
(Philosophie des Rechts, der Politik und der Gesellschaft: Akten des 12. Internationalen Wittgenstein Symposiums)