terms used for reporting observations are primitive, simple and fully determined by perception. These meanings were variously called “sensations”, “sense impressions”, “sense perceptions”, “sense data” or “phenomena” by different positivists. For these often called “phenomenalists” the sense perceptions are the object of knowledge rather than constituting knowledge thus making many versions of positivism solipsistic.
In the case of a term such as “black” the child’s ostensive acquisition of meaning might involve the child pointing his finger at a present instance of perceived blackness in some black object we call a “raven” bird. And then upon hearing the word “black” in repeated presentations of several other black objects, he associates the word “black” with his various experienced perceptions of the color black. Furthermore from the several early experiences expressible as “That raven is black” the young learner may eventually infer intuitively by natural inductive generalization that “Every raven is black.” However, solipsistic phenomenalism makes sharing such experiences philosophically problematic.
There are three characteristic theses in positivist semantics. They are:
- Meaning invariance.
- Analytic-synthetic dichotomy.
- Observation-theory dichotomy.
3.13 Positivist Thesis of Meaning Invariance
What is fundamental to the naturalistic philosophy of semantics is the thesis that the semantics of observation terms is fully determined by the ostensive awareness that is perception. Different languages are conventional in their vocabulary symbols and in their syntactical structures and grammatical rules. But according to the naturalistic philosophy of semantics nature makes the semantics of observation terms the same for all persons who have received the same perceptual stimuli that occasioned their having acquired their semantics in the same circumstances by simple ostension. Thus the natural semantics of a univocal descriptive term used to report observations is invariant through time and is independent of different linguistic contexts in which the semantics may occur; it is primitive and atomistic. Positivists viewed this meaning invariance as the basis for objectivity in science.
3.14 Positivist Analytic-Synthetic Dichotomy
In addition to the descriptive observation terms that have primitive and simple semantics acquired ostensively, the positivist philosophers also recognized the existence of certain terms that acquire their meanings contextually and that have complex semantics. An early distinction between simple and complex ideas can be found in his Essay Concerning Human Understanding by the seventeenth-century British empiricist philosopher John Locke. The positivist recognized compositional meanings for terms occurring in three types of statements: the definition, the analytic sentence and the theory:
The first type of term having complex semantics that the positivists recognized occurs in the definition. The defined subject term or definiendum has a compositional semantics that is exhibited by the structured meaning complex associated with the several words in the defining predicate or definiens. For example “Every bachelor is a never-married man” is a definition, so the component parts of the word “bachelor” are “never-married” and “man”.
The second type occurs in the analytic sentence, which is an a priori or self-evident truth, a truth known by reflection on the interdependence of the meanings of its constituent terms. Analytic sentences contrast with synthetic sentences, which are a posteriori, i.e., empirical, and are thus deemed to have independent meanings for their terms. The positivists view the analytic-synthetic distinction as a fundamental dichotomy between the two types of statements. A similar distinction between “relations of ideas” and “matters of fact” can be found in An Enquiry Concerning Human Understanding by the seventeenth-century British empiricist philosopher David Hume.
An example of an analytic sentence is “Every bachelor is unmarried”. The semantics of the term “bachelor” is compositional and is determined contextually, because the idea of never having been married is by definition included as a component part of the meaning of “bachelor” thus making the phrase “unmarried bachelor” redundant. Contemporary pragmatists such as Quine in his famous paper “Two Dogmas of Empiricism” reject the positivist thesis of a priori truth. Quine maintains that all sentences are empirical.
3.15 Positivist Observation-Theory Dichotomy
Positivists alleged the existence of “observation terms”, which are terms that reference observed entities or phenomena. Observation terms are deemed to have simple, elementary and primitive semantics and to receive their semantics ostensively and passively. Positivists furthermore called the particularly quantified sentences containing only such terms “observation sentences”. For example the sentence “That raven is black” uttered while the speaker of the sentence is viewing a present 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.
