Thomas J. Hickey

Twentieth-Century Philosophy of Science: A History (Third Edition)


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raven, is an observation sentence.

      In contrast to observation terms there is a third type of term having complex semantics that the positivists called the “theoretical term”. The term “electron” is a favorite paradigm for the positivists’ theoretical term. The positivists considered theoretical entities such as electrons to be postulated entities as opposed to observed entities like elephants. And they defined “theory” as sentences containing any theoretical terms. Many positivists view the semantics of the significant theoretical term as simple like the observation term even though its semantics is not acquired by observation. Carnap was a more sophisticated positivist. He said that the definition determines the whole meaning of the defined term, while the theory determines only part of the meaning of the theoretical term, such that the theoretical term can acquire more meaning as the science containing it develops.

      Nominalists furthermore believe that theoretical terms are meaningless, unless these terms logically derive their semantics from observation terms. On the nominalists’ view terms purporting either unobserved entities or phenomena not known observationally to exist have no known referents and therefore no semantical significance or meaning. For example the phrase “tooth fairy” is meaningless, since all fairies are deemed mythical and thus never to have been observed. For nominalists theoretical terms in science receive their semantics by logical connection to observation language by “correspondence rules”, a connection that produced what positivists called “logical reduction to an observation-language reduction base”. Without such connection the theory is deemed to be meaningless and “metaphysical”.

      Both the post-positivist Karl Popper and later the logical positivist Carl Hempel have noted that the problem of the logical reduction of theories to observation language is a problem that the positivists have never solved, because positivists cannot exclude what they considered to be metaphysical and thus meaningless discourse from the scientific theories currently accepted both by the neopositivists and by contemporary scientists.

      In summary the positivists recognized the definition, the analytical sentence and the theory sentence as exhibiting composition in the semantics of their constituent subject terms.

      3.16 Contemporary Pragmatist Semantics

      Philosophers’ reflection on the development of quantum physics occasioned development of the contemporary pragmatist philosophy. A fundamental postulate in the contemporary pragmatist philosophy of language is the rejection of the naturalistic thesis of the semantics of language and its replacement with the artifactual thesis that relativizes all semantics and ontology to linguistic context consisting of universally quantified beliefs. The rejection of the naturalistic thesis is not new in linguistics, but it is fundamentally opposed to the positivism that preceded contemporary pragmatism.

      3.17 Pragmatist Semantics Illustrated

      Consider the following analogy illustrating relativized semantics. Our linguistic system is analogous to a mathematical simultaneous-equation system. The equations of the system are a constraining context that determines the variables’ numerical values constituting a solution set for the equation system. If there is not a sufficient number of constraining equations, the system is underdetermined such that there are an indefinitely large number of possible numerical solution sets.

      In pure mathematics numerical underdetermination can be eliminated and the system can be made uniquely determinate by adding related independent equations, so there are just as many equations as there are variables. Then there is one uniquely determined solution set of numerical values for the equation system.

      When applying such a mathematically uniquely determined equation system to reality as in basic science or in engineering, the pure mathematics functions as the syntax for a descriptive language, when the numerical values of the descriptive variables are measurements. But the measurement values make the mathematically uniquely determined equation system empirically underdetermined due to measurement errors, which can be reduced indefinitely but never completely eliminated. Then even for a mathematically uniquely determined equation system admitting only one solution set of numerical values, there is still an infinitely large number of possible measurement values falling within even a narrow range of empirical underdetermination due to measurement errors.

      When the simultaneous system of equations expresses an empirical theory in a test, and if its solution-set numerical values fall within the estimated range of measurement error in the corresponding measurement values produced in the test, then the theory is deemed not falsified. But if the solution-set numerical values are outside the estimated range of measurement error in the measurement values, then the theory is deemed to have been falsified by all who accept the test design and its execution.

      The language system is like a mathematically underdetermined equation system having an infinitely large number of solution sets for the system. A set of logically consistent beliefs constituting a system of universally quantified related statements is a constraining context that determines the semantics of the descriptive terms in the belief system. This is most evident in an axiomatized deductive system. Like the equation system’s numerical values the language system’s semantics for any “semantical solution set”, as it were, are relativized to one another by the system’s universal beliefs and have definitional force. But the semantics conceptualizing sense stimuli always contains some vagueness. Due to this vagueness the linguistic system is empirically underdetermined and admits to an indefinitely large number of relativized semantical sets for the system. There is no uniquely determinate belief system of concepts.

      This vagueness does not routinely manifest itself or cause communication problems so long as we encounter expected or familiar experiences for which our conventionalized beliefs are prepared. But the language user may on occasion encounter a new situation, for which the existing relevant conventional beliefs cannot take into account. In such new situations the language user must make some decisions about the applicability of one or several of the problematic terms in their existing beliefs, and then add some new beliefs or reject some currently accepted beliefs, if the decision about applicability is not simply ad hoc.

      Adding more universally quantified statements to the belief system reduces this empirical underdetermination by adding clarifying information, but the residual vagueness can never be completely eliminated. Our semantics captures determinate mind-independent reality, but the cognitive capture with our semantics can never be exhaustive. There is always residual vagueness in our semantics. Vagueness and measurement error are both manifestations of empirical underdetermination. And increased clarity reduces vagueness as increased accuracy reduces measurement error.

      Relativized semantics also has implications for ontology. Mind-independent recalcitrant reality imposes the empirical constraint that makes our belief systems contingent, and in due course falsifies them. Our access to mind-independent reality is by language-dependent relativized semantics, which signifies a corresponding ontology. Ontology is the cognitively apprehended aspects of the fathomless plenitude that is mind-independent reality as described by the relativized semantics. Thus there are no referentially absolute or fixed terms. Instead descriptive terms are always fuzzy, i.e., referentially indeterminate or as Quine says “inscrutable”, because their semantics is always empirically underdetermined.

      Three noteworthy consequences of the artifactual thesis of relativized semantics are:

      -Rejection of the positivist observation-theory dichotomy,

      -Rejection of the positivist thesis of meaning invariance.

      -Rejection of the positivist analytic-synthetic dichotomy.

      3.18 Rejection of the Observation-Theory Dichotomy

      All descriptive terms are empirically underdetermined, such that what the positivists called “theoretical terms” are simply descriptive terms that are more empirically underdetermined than what the positivists called “observation terms”.

      One of the motivations for the positivists’ accepting the observation-theory dichotomy is the survival of the ancient belief that science in one respect