I wish to introduce you to the work of an obscure Austrian philosopher. His name is Otto Otto and he lives in the suburbs of Vienna.  He belongs to a group called the Vienna Oval by facetious analogy with the better-known Vienna Circle. Otto (you can take this to be his first or last name according to preference) is a positivist strict and pure, old school to the core. He accepts the verifiability criterion of meaning without dilution or compromise: every meaningful statement must be verifiable. He differs from other positivists, however, in two particulars: he doesn’t think that ordinary empirical statements are verifiable, and he does think that a priori truths are. In particular, he holds that analytic truths are the paradigm of verifiability. He thus maintains that analytic and other a prioristatements are straightforwardly meaningful while empirical statements are not. His reason for denying the verifiability of empirical statements is not eccentric: it lies in the power of skepticism. Skepticism teaches us that our ordinary statements of science and common sense are not rationally justifiable, i.e. not verifiable. According to the verifiability principle, then, they are not meaningful. Since we could be brains in a vat, we can’t justify statements about the external world, which means they are not verifiable; and hence they cannot be meaningful. However, we can justify analytic statements, because the skeptic cannot cast doubt on our acceptance of them: we know for sure, for example, that bachelors are unmarried males. So analytic statements are meaningful, but empirical statements are not. That is Otto’s considered position and he sees no reason to deviate from it.
Now Professor Otto is not an unreasonable man: he is aware that his position might strike some as extreme, even perverse. For how can it be that science and common sense are literally meaningless? Here he is prepared to hedge a bit: they may be agreed to have a kind of secondary semantic status. Conventional positivists make this kind of compromise all the time: they accept that a priori statements are meaningful without being empirically verifiable, holding them to be tautologies devoid of real content; and they also recognize the existence of meaningful ethical statements. They accordingly speak of “cognitive meaning”, contrasting it with lesser kinds of meaning; they operate, in effect, with a semantic caste system. Likewise Otto and his comrades accept that empirical statements have a kind of second-class semantic status: they have a use, a role on communication, even if they lack meaning proper. They lack what Otto is pleased to call logical meaning or rational meaning or epistemic meaning, but they do have pragmatic meaning—meaning in the vernacular non-rigorous sense. They have the same status as tautologies in the rival positivist worldview: tautologies are not meaningful in the sense of being informative and fact stating, but only in the lesser sense that they are grammatically well-formed and composed of meaningful elements. Likewise Otto and his associates accept that empirical statements are grammatical and composed of meaningful elements, but they deny that such statements have the kind of serious substantial meaning possessed by statements you can rationally accept as true. They wonder what the point is of statements that cannot be used to express knowledge, as empirical statements cannot (because of skepticism). True, such statements are not literal nonsense, either by grammar or lexicon, but they can’t match a priori statements for their ability to express ascertainable knowledge. The latter statements are genuinely cognitive in the sense of being knowledge expressing, while empirical statements exist in a limbo of uncertainty. Otto privately condemns empirical statements as sheer nonsense, in his strict and pure sense, but he publicly concedes that they have a kind of degenerate meaning—just as the Circle positivists do the same for analytic statements and ethical statements. What Otto can’t fathom is why these putative positivists believe that empirical statements are meaningful and yet are not verifiable—given that they accept the verifiability theory of meaning. Don’t they see that no empirical statement can be established as true, or even asserted in preference to its negation, given that the skeptic is undeniably right? They fail to understand that a priori statements are the only kind that allow of conclusive verification, and hence qualify as meaningful. Even if they are mere tautologies—which Otto strongly contests—they are at least verifiable tautologies: you can at least know them to be true! You know them to be true by the exercise of reason and knowledge of meaning, whereas the senses can never deliver skepticism-proof knowledge. The problem of induction by itself shows that laws of nature cannot ever be known, so such statements are not verifiable, and hence not meaningful. On the other hand, we can know with certainty that bachelors are unmarried males and that 2 plus 2 equals 4. Thus the principle of verifiability shows that only a priori statements are meaningful in the gold-standard sense, with empirical statements trailing somewhere in the semantic dust. They are meaningful only in the sense that “Colorless green ideas sleep furiously” is meaningful, i.e. they are grammatical and composed of meaningful elements. Otto’s position is rather like the position that would have been taken by Popper had he been interested in criteria of meaningfulness: empirical statements can never be verified (though they may be falsified), and so cannot be strictly meaningful. Otto and friends adopt the simple view that meaning requires the possibility of knowledge, and only a priori statements can really be known to be true. They regard the rival band of positivists as sloppy weak-kneed thinkers who refuse to accept the problem of empirical knowledge—don’t they see that no empirical statement has ever been verified? Authentic positivism thus requires us to accept that empirical discourse is strictly meaningless save in a second-class by-courtesy-only sense. It is meaningful only in the way ethical discourse is meaningful, i.e. by dint of grammatical correctness and pragmatic utility.
What view does Otto’s school of positivism take of metaphysical discourse? One might think they would be tolerant of it since it purports to be a priori, but actually they are as intolerant of it as their rivals in central Vienna. The reason is simple: such statements are never rationally justifiable. No metaphysician can ever establish the truth of his assertions: there is no method of acquiring metaphysical knowledge. It isn’t the lack of empirical content that is the problem—that applies equally to mathematical knowledge—but the problem of not having any effective method of delivering knowledge. No proof procedures and no simple unfolding of meaning, just endless wrangling and futile dispute. So metaphysics is as meaningless as the other positivists maintain but for a different reason. Empirical justification is neither here nor there; what matters is that there be some method for finding out the truth. As to ethics, Otto is ambivalent: he is inclined to regard it as a priori, and he accepts that ethical reasoning is rational, but he is disturbed at the lack of consensus about ethical questions. He is apt to call ethical statements “quasi-meaningful”: they have emotive meaning, to be sure, and they permit rational inference, but they lack the kind of certainty we find in mathematics, logic, and analytic truth. Ethical statements are not as meaningful as statements in these areas, though they are a lot more meaningful than statements of physics, say, with its unverifiable induction-based statements of natural law. Nothing meaningful is unjustifiable, so ethics squeaks in by comparison with science: after all, it has a strong a priori component. But science is stuck in unverifiable limbo: for none of it can be proved. Here Otto is a Popperian: Hume was right about induction, and that means that scientific theories can never be rationally established (though they may be refuted). As Otto likes to say, science never expresses genuine propositions—things that can be true or false—though it can bandy around sentences that are instrumentally useful and are clearly grammatical.
Otto suspects that the other positivists are unduly influenced by religion. They see that religion is not an area of rational inquiry in good standing, and that it is dubiously meaningful, so they naturally seek to ban it. But they wrongly locate the central defect of religion: it isn’t that it lacks empirical credentials but that it lacks any procedure for establishing its claims. It doesn’t have the methodological clarity of the analytic, the logical, and the mathematical. In fact, it does have empirical criteria of justification; it is just that these criteria tend to undermine its truth (all those alleged miracles never pan out empirically). The reason it is not meaningful is that its claims are not susceptible to rational demonstration—not rationally verifiable. Faith is not rational demonstration, so faith cannot supply meaning. The other positivists wrongly contrast religion with science, thinking that science supplies the paradigm of the meaningful for the true positivist; but science is not strictly meaningful by correct positivist standards. Rather, religion and science are both condemned to semantic destitution, according to the proper form of positivism—the kind that links meaning with rational provability. The problem with religious claims is just that there is no rational way to demonstrate them. If they were analytic everything would be fine (the ontological argument was a valiant effort in that direction), but they clearly are not—they don’t just spell out what the word “God” means. Nor are they mathematical in nature. So there is no way to justify them by rational criteria. The positivists were right to find a tight connection between meaning and knowledge, but they wrongly located this connection in empirical knowledge—of which there is no such thing. They were logical empiricists where they should have been logical rationalists: pure reason can establish the truth of propositions, and hence guarantee meaning, but the senses combined with induction are impotent to establish anything, so they cannot be the source of meaning. Skepticism disproves classical positivism, but it leaves Otto’s version of positivism untouched, or so he contends. 
 Did I mention that Otto Otto is a mathematician by training and also an accomplished logician? He is also fond of compiling synonyms. Empirical science leaves him cold because of its lack of formal rigor and its inconclusive methods. This may have something to do with his insistence that real meaning lies in the a priori sciences; he is certainly snooty about the mathematical capabilities of members of the Vienna Circle (those mathematical illiterates, as he refers to them). In fact, he lumps them together with the metaphysicians in their shared lack of methodological scruples. Empirical science is far too much like metaphysics, in his book.