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| Verifiability Principle |
The doctrines associated with the slogan that meaning is the mode of verification continued to develop in the last four decades of the twentieth century. While the exact formulation of the principle was itself controversial, the essential idea was to link semantic and epistemic concerns by letting the meaning of an expression be its role within an empirical epistemology.
At the same time the fortunes of logical empiricism, the movement associated with verificationism, changed substantially as well. First, as philosophers who conspicuously did not identify themselves with logical empiricism moved to center stage, the movement as a separately identifiable phenomenon virtually ceased to exist.
This did not dispose of verificationism, however, for often the later philosophers’ views were strikingly similar to the logical empiricism that they supposedly replaced, just as the criticisms of logical empiricism were often pioneered by the logical empiricists themselves. The second major change in the fortunes of this view was the renewal of interest in the history of philosophy of science, especially in the histories of the logical empiricists themselves.
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| logical empiricism |
Now freed from the myopia that comes from being part of the fray, philosophers were able to explore the roots of logical empiricism, what held it together as a movement, which of its doctrines were central or peripheral, and even which views look more plausible in hindsight than they did before their systematic interconnection could be appreciated.
One root of verificationism lies in the increasing professionalization of both the sciences and philosophy around the turn of the twentieth century. The sciences tended to emphasize the importance of empirical investigation, to explore its scope and limits, and to deplore as metaphysical any claims not based on evidence.
Correspondingly, many philosophers claimed for themselves a nonempirical source of knowledge concerning things higher or deeper than mere observation could reveal, that is, concerning metaphysics. Logical empiricism grew out of methodological discussions within science rather than philosophy, and many of its central proponents were trained in the sciences.
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| mathematics and logic |
True, logical empiricism made special accommodation for the a priori domains of mathematics and logic. But these were technical subjects of use within the sciences and for which there were increasingly well-developed modes of conflict resolution.
Moreover, the way in which the accommodation was reached, namely through the logical analysis of language, especially the language of science, comported well with a basic empiricism and provided no comfort to traditional philosophy.
A second root of verificationism lies in Bertrand Russell’s reaction to the paradox that bears his name (viz., a contradiction that arises when sets can contain themselves) and in Ludwig Wittgenstein’s further elaboration of a related idea.
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| the paradox |
In order to avoid the paradox, Russell had restricted the grammar so that apparent assertions of sets containing themselves were no longer well formed. Similarly, Wittgenstein emphasized that some combinations of words were neither true nor false but just nonsensical; they were, he said, metaphysical.
This seemed to offer the ideal diagnosis of the sought-after distinction: Scientifically respectable claims were either empirically meaningful in virtue of having some appropriate relation to the observations that would be the source of their justification, or else they were true in virtue of the language itself; traditional metaphysics, by contrast, was simply unintelligible. Phrased in this way, the verifiability principle leaves as a separate question the issue of what the appropriate relation to observation would be.
It has also become clearer what the logical status of the principle itself is. Initially, these philosophers could imagine that they were saying something about language in general or about the language of science.
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| the principle |
But as it became apparent that there were alternative languages to be considered, it became obvious that the principle could be put as a proposal for a language or as an analytic or empirical claim either about a particular language or about a range of languages.
Perhaps the dominant form of the principle is as a proposal for a language to explicate the linguistic practices that are already largely in place in the sciences. As a proposal, it is not a claim, and hence neither true nor false, but not thereby unintelligible.
If the proposal is adopted, the corresponding claim about the language that has those rules would be analytic. There would also be the empirical claim that we had adopted such a language and even empirical claims about that language if it were specified as, say, the language that is now used in contemporary physics.
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| misunderstanding |
So construed, many of the objections that were first made to the principle (and which continued to be made through the period in question) can be seen to be wrongheaded. The most persistent of these criticisms is that the principle renders itself an unintelligible claim. Whether construed as a proposal, as an analytic claim, or as an empirical one, this is just a (willful) misunderstanding.
The same can be said for the criticism that it renders all philosophy meaningless. Equally misguided is the repeated objection that the principle cannot be right because we can understand a sentence without knowing whether it is true. Obviously, the principle in no way denies this truism.
Potentially more serious is the idea that all attempts to specify the principle have failed and are thus likely to continue to do so. Reinforcing this idea are papers by Carl Gustav Hempel (1950, 1965) that, while they are not really histories, strike many readers as signed confessions of complicity in a series of disasters.
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| Wittgenstein |
In defense of the principle it must be said that, except for those immediately around Wittgenstein, complete verifiability was virtually never at issue. Even in the Aufbau, where the general question is raised many times, all but one formulation are much more liberal. Similarly, strict falsifiability was never proposed as a criterion of meaningfulness.
Concerning the more fertile ground of confirmation and disconfirmation, the difficulties seem to have arisen because the formulations tried both to link semantic and epistemic concerns and to specify a complete theory of confirmation.
This latter task is so difficult that we should not expect early success nor conclude from failure that the enterprise is misguided—any more than we give up physics simply because we still lack the final theory.
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| meaningless parts |
There were, of course, other sources of difficulty. Many attempts, such as A. J. Ayer’s, tried to apply a criterion of meaningfulness at the level of whole sentences even though those sentences could contain meaningless parts.
More successful in this regard was Rudolf Carnap’s “Methodological Character of Theoretical Concepts” (1956), which applied the criterion at the level of primitive terms. In a paper that was famous despite being unpublished for many years, David Kaplan (1975) provided two counterexamples to Carnap’s criterion.
These examples were widely regarded as decisive, but Richard Creath (1976) showed that one of the examples missed its mark and the criterion could be patched in a natural way so as to avoid the other. Less easily dismissed is W. Rozeboom’s (1960) criticism that Carnap’s criterion ties meaningfulness to a particular theory when it should apply only to the language.
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| level of vocabulary |
Finally, Carnap’s criterion, like many others, seems to presuppose that the theory/observation distinction can be drawn at the level of vocabulary. There came to be general agreement that this presupposition is mistaken and distorts any criterion based on it.
In fairness, it must be admitted that some theory/observation distinction is essential to a healthy empiricism and that Carnap was from the very beginning fully aware of the limitations of formulating the distinction in this way. Finding a satisfactory way is still an unsolved problem.
W. V. O. Quine is often associated with the demise of logical empiricism, and his “Two Dogmas of Empiricism” (1951) is often thought to have rejected verificationism decisively. It would be more accurate to say that he rejected the idea that individual sentences could be separately confirmed, but he did not resist linking meaningfulness with confirmation holistically construed.
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| correspondence rules |
Indeed, his demand that behavioral criteria be provided for analyticity to render it intelligible is exactly parallel to Carnap’s demand for correspondence rules to render theoretical terms meaningful.
Moreover, Quine’s argument from the indeterminacy of translation to the unintelligibility of interlinguistic synonymy makes sense only if meaning and confirmation are somehow linked as in the verifiability principle.
So what then of this link between semantic and epistemic issues? At least there is much to be said for it. A theory of meaning should give accounts of meaningfulness (having a meaning), of synonymy (having the same meaning), and of understanding (knowing the meaning). The verifiability principle provides a way of doing these things not provided by simply identifying various entities as “the meanings” of expressions.
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| skepticism |
Moreover, it provides a defense against wholesale skepticism by tying what we know to how we know. And finally, it provides a way of dealing with the so-called a priori by making those claims knowable in virtue of knowing the meanings of the expressions involved.
No doubt there are others ways, perhaps even equally systematic ways, of accomplishing these ends, and no doubt these other paths should be investigated as well. But the basic idea behind the verifiability principle, namely that semantical and epistemic questions should be linked, is far from refuted, and its promise is far from exhausted.
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| epistemic questions |
