Verificationism has had an interesting history in 20th century anglophone philosophy. The story goes, as I understand it, that during one of the famous Vienna Circle meetings, Wittgenstein said in conversation that the meaning of a word was its mode of verification. The Circle members, Carnap, Schlick, Fiegl, etc., thought that this was really quite novel and good. They latched onto it and, as I understand it, Wittgenstein thought it quite silly for them to do so. He had just said it in passing, after all. Carnap especially began writing about it, and later logical positivists like A. J. Ayer gave it a good run.
The verification thesis turned out to be not only the central weapon of logical positivism, but also its Achilles heel. Combine it with the analytic/synthetic distinction that was also fundamental to logical positivism and you ended up with the awkward question of whether the verification thesis was itself analytic or synthetic, given by language or verifiable by experience. That question is what brought down logical positivism in its early, naive stage.
But then we get to Quine's attack on the analytic/synthetic distinction. The basic outcome of that attack was that language, rather than being something that could be canvassed a priori, was itself also experiential, synthetic as it were. This gave new breath to something like verificationism, such that it became not a thesis about checking language against something else, but a basic metaphilosophical position about being able to come up with criteria for confirming or disconfirming such-and-such thesis. This makes verifiability internal to a language game, rather than between a language game and reality.
Pirsig comes close to something like this kind of verificationism in the beginning of Lila (Chapter 8), but I think he halts at the doorsteps because he still holds to some kind of sense-data empiricism of the kind analytic philosophy had left behind after Quine. One way of enunciating the difference is by looking at Pirsig's desire to call Quality the "ultimate reality." What could possibly confirm or disconfirm the truth of "Quality is the ultimate reality"? The difficulty of metaphysics (defined as the search for ultimate reality) was that there never seems to be a way of shutting the skeptic up: "How do you know Quality is the ultimate reality?" Pirsig seems to think we can shut him up by pointing to the mystic and saying, "Ah, but he cuts through the appearances to reality." That the mystic confronts ultimate reality directly, and so can verify it experientially. But how do we know the mystic has confronted ultimate reality?
Once we move ultimate reality to the realm of experience, the realm of the verifiable, the most important question we need to ask is what should any of us do when confronted with a personal account of the direct confrontation of the ultimate reality? What are we supposed to think of them, and why?
For example, the other day my roommate and I were sitting around talking and she recounted a dream she had. She dreamt she was in a store somewhere holding three black objects and then she suddenly dropped them. Two days later she was at Target with her mother. Mom was buying three watches, each in a black case. She asked my roommate to hold on to them, and a minute later she dropped them—three black objects. She had a major case of déjà vu and I off-handedly commented that she was experiencing some precognition in her dream. She said, "Yeah…isn't it weird how sometimes you're really connected with these things. Sometimes you can be more with it and you start getting those things more." I smiled and she's like, "Ah, I'm guessing you're a non-believer." Yeah, pretty much.
But how am I supposed to receive first-hand accounts like that? Obviously my roommate is no mystic, but it was a personal experience of "something else" wasn't it? I told her that, though I don't believe for a second that she suffered from precognition, or you could be more "with it," more "connected," the one thing I couldn't do was tell her that she didn't experience it. I could only give her alternate explanations of what it was that she experienced.
But, again, how am I supposed to take those personal experiences? Are we to take any damn fool thing a person says seriously (assuming they say it sincerely)? This is what we might call the shibboleth problem. The story goes that one of the Israelite Judges, Jephthah, went to war and not all of the tribes went with him. Well, Jephthah won and when the tribes were coming home he wanted to weed out the ones who hadn't supported him. One of the tribes had trouble pronouncing the word "shibboleth." So Jephthah had everybody coming over the river say "shibboleth," and whoever said "sibboleth," as the one tribe would pronounce it, was killed.
So, because of the story, shibboleth has come to mean a "key word." To tell the real mystics from the fakers, or worse, the simply wrong, we need to be able to tell if they are saying "shibboleth" or not. The problem isn't whether they are saying "shibboleth," whether they are, in fact, real mystics, the problem is how would we ever know if they were? How can we tell the Buddhas from the Call-In Cleos?
The only answer I can figure is through conversation, but the end result of that answer means that the only way we can tell a real mystic from someone who hasn't penetrated appearance to reality is by behavior, by the mystic behaving in accordance to established canons of experience, canons built by the success of earlier mystical sayings, which means that they must be behaving according to the conventions of an established tradition, a tradition that would deem them a mystic. The end result of this line, I think, is that the only practical thing that matters, then, isn't whether there was any penetration to reality or not, but the results of the conversation itself. The conversation is what matters, the inquiry is what matters, not whether we say that they penetrated beyond appearances.
This is the fruit of verificationism. It means that a tradition of discourse is what contains the routes of confirmation and disconfirmation for a proposition. Verificationism is still, in the hands of pragmatists rather than positivits, a weapon for destroying metaphysics. As Rorty says, "that is, pragmatists think our inability to say what would count as confirming and disconfirming a given solution to a problem is a reason for setting the problem aside." (CP, xxiii) The trick is to de-transcendentalize metaphysics, to take the appearance/reality distinction out of metaphysics and so make traditions, be them science, art, or morality, attempts to cope with experience. What counts as successful coping is determined internally to the tradition. This reconstitutes the traditions as Pirsig wanted, but leaves aside questions of "ultimate reality". If we can't tell whether they are saying shibboleth or not by any of the lights we have available, then it probably isn't worth thinking about.