RUDOLF CARNAP ON SEMANTICAL SYSTEMS AND
W.V.O. QUINE'S PRAGMATIST CRITIQUE
BOOK III - Page 9
Comment and Conclusion
While the semantical wholism of the Duhem-Quine thesis has received much attention, it is seldom realized that Quine’s rejection of all first philosophy is one of its most consequential implications for philosophy of science. When the Duhem thesis of physical theory is extended to the whole of language, not only is all semantics relativized by context-determination, but also all ontologies described by the relativized semantics are made vulnerable to empirical criticism; there are no longer any privileged or protected ontologies.
Quine’s thesis of ontological relativity has the historic and revolutionary effect of excluding all ontological considerations from the criteria for scientific criticism. In his philosophy it is empirical adequacy of scientific theories alone that decides ontological questions, rather than prior ontological commitments that decide the acceptability of scientific theories.
Quine subordinates all questions of ontology to the empirical adequacy of the theory affirming the ontological claims in question. He maintains that the human knower can never do better than to occupy the standpoint of one or another theory, whether the theory purports the existence of either macrophysical or microphysical entities. All entities are “posits” affirmed by one or another theory, and all are worthy of our patronage just to the extent that the theory positing them is empirically adequate. However detailed may be the relevant observation language, empirical underdetermination and its consequent semantical indeterminacy always admit alternative choices of theory. And the consequent referential inscrutability, i.e., ontological relativity, may admit to as many correspondingly alternative choices of entities.
Quine’s rejection of prior ontological criteria in scientific criticism is also consistent with scientific realism, which gives the tested and nonfalsified explanation the rôle of defining ontology. Realism is not established by science; it is a prior prejudice. But science lets empirical adequacy justify the ontological claim that an explanation describes the real world. This thesis is not only characteristic of the contemporary pragmatist philosophy, but was also the practice of such scientists as Galileo, Einstein and Heisenberg. In developing his theory of relativity Einstein posited relativistic time as real instead of Newton’s absolute time, and he rejected Lorentz’s relegation of relativistic time to the status of apparent time and Lorentz’s retention of Newton’s absolute time as real. A central thesis of the Copenhagen interpretation, or at least Heisenberg’s noninstrumentalist version, is its realistic claims about the wave-particle duality and the indeterminacy principle, and Heisenberg referenced Einstein’s realism in relativity theory as a precedent. The practice of letting the empirical adequacy of a theory operates as the criterion for the acceptability of its ontology did not begin with Einstein or Heisenberg. A historic and well known example is Galileo’s realistic interpretation of the Copernican theory, which placed him in conflict with the Aristotelian ontology enforced by the Roman Catholic Papacy.
This is a distinctively and thoroughly pragmatist view that separates Quine from both his positivist and romanticist predecessors. Ironically it also separates him from certain other aspects of his own philosophy. One such aspect is his behavioristic epistemology. The romanticists insist upon and the positivists insist against the introduction of “mentalism” in explanations in the social and behavioral sciences. But on the contemporary pragmatist philosophy of science, this ontological issue is decided by the empirical adequacy of the behavioral and social science theories. Different theories in different sciences at different times or even at the same time will admit different ontologies. Quine’s behavioristic “naturalized” epistemology is actually an exception to his thesis of ontological relativity.
Another such inconsistent aspect is Quine’s ontological reductionism and his consequent de facto nominalism. In his “Introduction” to his Dear Carnap, Dear Van Richard Creath states that Quine’s ontological reductionist agenda was due to Quine’s interpreting Carnap’s Logical Syntax in a manner that was nearly wholly unintended by Carnap. Carnap argued in Logical Syntax that talk which appears to be about possibilities, properties, relations, numbers, etc. can be reconstrued to be talk about sentences, predicates, etc. Creath says that in Quine’s “Lectures on Carnap”, a prepublication report on the theses of Logical Syntax given to the Society of Fellows at Harvard in 1934, Quine had interpreted Carnap to mean that there are no such metaphysical entities, and that philosophy therefore is syntax as a program of ontological reduction. Creath states that in fact Carnap actually rejected both the affirmation and the denial of the existence of such metaphysical entities as properties, because Carnap believed at the time that such discourse is metaphysical nonsense. Later Carnap took a more pragmatic view of such entities as intensions and properties.
But for the duration of his career Quine continued in his ontological reductionist agenda, which apparently resulted from his early misinterpretation of Carnap, notwithstanding Quine’s later formulation of his ontological relativity thesis. This persistence is inconsistent; ontological relativity renders logical elimination for the purpose of ontological reduction a philosophically pointless exercise, because its acceptance implies the rejection of any and all prior ontological commitments that would motivate such ontological reductionism. Ontological relativity makes all ontological commitments a posteriori to empirical criticism, and together with the empirical underdetermination of all theories results in ontological pluralism, not reductionism. But Quine is neither the first nor the last philosopher-king to exercise a sovereign’s right of eminent domain in his own philosophy, and exempt his preferred convictions from his own laws.
Mach and Duhem were not only positivist philosophers of science; they were also practicing research physicists, who furthermore wrote histories of physics. Carnap on the other hand was neither a practicing research physicist nor a historian of physics. His philosophical work was remote from the physicists’ research practices, because the Vienna Circle had an epistemological (i.e., metaphysical) agenda for scientific criticism, which did not actually operate in research physics. Carnap aimed to construct a metalogic for science, but he did not apply his constructionalist techniques to the language used by scientists. Instead he used the symbolic logic of Russell and Whitehead to substitute for the object language that he claimed he was investigating. But the symbolic logic is not useful to the physicist. Carnap and others such as Russell and Braithwaite hailed the development of the Ramsey sentence as a great philosophical achievement. But it would be a rare physicist who would consider the Ramsey sentence at all consequential to either the practice or the history of physics. The situation is aptly stated by Radnitzky in the “Epilogue” in the first volume of his Contemporary Schools of Metascience (1968), where he says that the logical empiricists had not produced any metascience at all, because they did not study the producers of scientific knowledge or the production or even the results. The post-positivist philosophers rejected logical positivism because they correctly recognized its irrelevance to research science and its inadequacy as a philosophy of science.
When the post-positivist philosophers rejected positivism, many of them also rejected its constructionalism. Many pragmatists in particular found their wholistic concept of the semantics of language incompatible with the mechanistic and procedural character of logical constructionalism. In the wholistic view the semantics of science makes the development of science a nonlogical process. But they rejected too much, because the logical positivists’ linguistic-analysis approach is more valuable than either the Russellian symbolic logic or the logical positivist philosophy of science, which used the symbolic logic. In this age of the computerized discovery system Carnap’s constructionalism and his metatheory of semantical systems may with certain noteworthy modifications be carried forward into twenty-first century methodology of science. Several such modifications are as follows:
A first important modification is that the object language that is constructed by a discovery system is not the Russellian symbolic logic; it is the mathematical equations or other technical language actually used in the science under investigation. Scientists never use the Russellian symbolic logic for the expression of their theories, and Carnap’s use of the symbolic logic to express empirical science was never more than a caricature. In his Primer of Quantum Mechanics Marvin Chester explicitly renders notational conventions developed by 1933 Nobel-laureate Paul Dirac as descriptive language. Given Carnap’s interest in physics, his philosophical linguistic analyses would have been infinitely more interesting had he chosen Dirac’s operator calculus to illustrate the syntax, semantics, and pragmatics of an object language in science, especially with respect to his thesis of intensions and extensions. Carnap’s philosophy might have evolved considerably in the process of developing such a linguistic analysis.
A second modification of Carnap’s work is the use of a computer language for the metalanguage. The computer language gives the metalanguage a disciplined and procedural character that a colloquial metalanguage does not offer. The computer language in which the discovery system is written operates as a metalanguage in which the formation rules of the object language are expressed in computer instructions. The discovery system in other words is a metalanguage expressing a mechanized generative grammar that inputs, processes and outputs the object language of a science.
A third modification pertains to Carnap’s concept of semantical rules that interpret a semantical system. The semantical rules for interpreting a mechanically generated semantical system might be viewed as analogous to Carnap’s meaning postulates in that they may be stated in the object language, yet they are like Carnap’s rules of designation in that as semantical rules describing meaning they are viewed in the metalinguistic perspective and in logical supposition. Thus the classification of semantical rules is different; there are two types: The first type consists of those semantical rules that are the mechanically generated statements and equations. These consist of the statements constituting mechanically generated and empirically acceptable theories, the outputted theory statements that may be accepted as true however provisionally. But not all the semantical rules occurring in the object language are theories, whether or not mechanically generated. There is also the second type consisting of test-design statements, which are accepted as true independently of any statements of theory generated by the system to identify the subject of the test, so that the generated theory is not tautological and can be tested independently.
But the semantical rules for mechanically generated semantical systems are unlike Carnap’s meaning postulates, because they are not just analytical sentences. With Quine’s rejection of any distinctively analytic truth it is possible to view sentences as both analytic and synthetic, and the semantical rules that describe the semantical interpretation of the object-language statements must be viewed as both analytic and synthetic sentences. They are more like Quine’s “analytical hypotheses” or “discursive postulates”. These semantical rules might also be viewed as similar to Carnap’s reduction sentences, which he says determine only “part” of the meaning of theoretical terms. But Carnap has never explained how it is possible for the meanings of terms to have parts. Viewing the sentences as both analytic and synthetic enables the empirical statements constituting the generated theory to exhibit the parts of the meanings of their constituent terms, just as analytic statements always have. Test-design statements and discovery-system-generated theory statements, both of which are believed to be true for empirical reasons and not due to the meanings of their constituent terms, are object-language statements functioning as semantical rules, each of which contribute parts to the meaning of each of their common descriptive terms.
A fourth modification pertains to Carnap’s idea of a state description. The Carnapian state description is not a useful concept for describing the semantical systems generated by mechanized discovery systems. In fact it is not useful for science at all. It consists of “atomic” statements expressed in Russellian logic, and was conceived with the intent of explicating precisely the ideas of L-truth and A-truth. The semantical systems generated by the discovery systems contain only universal statements constituting the theories generated with the formation rules programmed in the computerized generative grammar. In contrast to the semantical systems in Carnap’s philosophy, which were devised for static analyses, the semantical systems in computational metascience are intended to describe the semantical changes occurring in the development of new theories, which development is a dynamic procedure.
Accordingly the Carnapian idea of a state description must be fundamentally revised for describing the computer system input and output object language, in order to reveal the semantical changes produced by the discovery system. The inputted information for the discovery system is drawn from the current cumulative state description consisting of the several theories that have been advanced to date by the particular scientific profession. These theories supply the vocabulary inputted to the computerized discovery system. This vocabulary has its semantics specified by semantical rules consisting of test-design statements, which are common to both input and output state descriptions. These test-design statements are not changed by the discovery system, and they supply semantical continuity for identifying the subject of the theories independently of the theories. The computerized discovery system generates an outputted state description consisting of alternative empirically adequate theories, which are semantical rules describing the semantics of the new theories.
A fifth modification consists of replacing Carnap’s theory of information with Shreider’s semantical metatheory, if the concept of state description as revised in the manner described above is identified with Shreider’s concept of thesaurus. But unlike Shreider’s theory there are actually two types of transformations involved. Firstly there is the mechanized syntactical transformation, the generation of new theories which are the output messages. And secondly there is also the semantical transformation on the part of the system users who communicate with the computer, when they attempt to interpret its output. The computer system is a transmitter and information source that generates message texts consisting of new theories. And the user receiving the message and having a thesaurus consisting of one of the input semantical systems, i.e., an old theory, must transform his mental thesaurus to conform to one of the output semantical systems, a new theory. The amount of information transmitted to a user depends on the degree of transformation between his initial mental thesaurus and the outputted theory that must transform the user’s mental thesaurus for him to understand the new theory.
The psychological resistance to this mental transformation might be large, if the amount of information communicated is large. And there may also a philosophical resistance depending on the using-scientist’s philosophy of science. If the scientist is a romantic social scientist, he will be philosophically ill disposed to accept the newly generated theories containing large amounts of information. He will find they are not “intuitively plausible” or “convincing” and do not “make substantive sense”. Romanticism retards the development of science, because it forbids the unfamiliar. Positivists also believe in the special importance of the familiar, which they call the “observable.” The philosophy of science that offers the least impediment to the reception of new information is pragmatism, according to which no prior ontology may serve as a criterion for scientific criticism.