a revolutionary change in scientific theory, such as the replacement of Newton’s theory of gravitation with Einstein’s, has the effect of changing only part of the semantics of the terms common to both the old and new theories. It leaves the semantics supplied by test-design language unaffected, so Arthur Eddington could test both Newton’s and Einstein’s theories of gravitation simultaneously by describing the same celestial photographic observations in his 1919-eclipse test. Thus contrary to Feyerabend there is no semantic incommensurability between these theories. And contrary to Feyerabend there is there no historical evidence that the advocates of Einstein’s relativity theory had failed to recognize that Einstein’s theory is an alternative to Newton’s.
Readers wishing to know more about the philosophies of Kuhn, Feyerabend, and Eddington’s 1919-eclipse test are referred to BOOK VI below.
3.23 Componential Artifactual Semantics Illustrated
The set of affirmations believed to be true and predicating characteristics universally and univocally of the term “raven” such as “Every raven is black” are semantical rules describing component parts of the complex meaning of “raven”. But if a field ornithologist captures a red bird specimen that exhibits all the characteristics of a raven except its black color, he must make a decision. He must decide whether he will continue to believe “Every raven is black” and that he holds in his birdcage some kind of red nonraven bird, or whether he will no longer believe “Every raven is black” and that the red bird in his birdcage is a red raven. Thus a semantical decision must be made. Color could be made a criterion for species identification instead of the ability to breed, although many other beliefs would also then be affected, an inconvenience that is typically avoided as a disturbing violation of the linguistic preference that Quine calls the principle of “minimum mutilation” of the web of belief.
Use of statements like “Every raven is black” may seem simplistic for science (if not quite bird-brained). But as it happens, a noteworthy revision in the semantics and ontology of birds has occurred due to a five-year genetic study launched by the Field Museum of Natural History in Chicago, the results of which were reported in the journal Science in June 2008. An extensive computer analysis of 30,000 pieces of nineteen bird genes showed that contrary to previously held belief falcons are genetically more closely related to parrots than to hawks, and furthermore that falcons should no longer be classified in the biological order originally named for them. As a result of the new genetic basis for classification, the American Ornithologists Union has revised its official organization of bird species, and many bird watchers’ field guides have been revised accordingly. Now well informed bird watchers will classify, conceptualize and observe falcons differently, because some parts of the meaning complex for the term “falcon” have been replaced with a genetically based conceptualization. Yet given the complexity of genetics some biologists argue that the concept of species is arbitrary.
Our semantical decisions alone neither create, nor annihilate, nor change mind-independent reality. But semantical decisions may change our mind-dependent linguistic characterizations of mind-independent reality and thus the ontologies, i.e., the various aspects of reality that the changed semantics reveals.
3.24 Semantic Values
Semantic values are the elementary component parts distributed among the meaning complexes associated with the descriptive terms of a language at a point in time.
For every descriptive term there are several semantical rules with each rule’s predicate describing some component parts of the common subject term’s meaning complex. A linguistic system therefore contains elementary components of meaning complexes that are shared by many descriptive terms, but are almost never uniquely associated with any single term, because all words have dictionary definitions analyzing the lexical entry’s component parts. These elementary components may be called “semantic values”.
Semantic values describe the most elementary ontological features of the real world that are distinguished by a language at a given point in time, and are the smallest elements in any meaning complex at the given point in time. The indefinitely vast residual reality not captured by any semantic values and that the language user’s semantics is unable to signify at the given point in time constitutes the empirical underdetermination of the whole language at the given point in time.
Different languages have different semantics and therefore display different ontologies. Where the semantics of one language displays semantic values not contained in the semantics of the other, the languages are said to be semantically incommensurable. Translation is therefore made imprecise.
A science at different times in its history may also have semantically incommensurable language, when the later version contains semantic values not contained in the earlier. But such incommensurability is rare, because it is routinely possible to resort to what Hanson called “phenomenal seeing”. And incommensurability does not occur in scientific revolutions understood as theory revision, because the revision is a reorganization of pre-existing information. When incommensurability occurs is it at times of discovery occasioning articulation of new semantic values due to new observations.
3.25 Univocal and Equivocal Terms
The definitions of descriptive terms such as common nouns and verbs in a unilingual dictionary function as semantical rules. Implicitly they are universally quantified logically, and are always presumed to be true. Usually each lexical entry in a large dictionary such as the Oxford English Dictionary offers several different meanings for a descriptive term, because terms are routinely equivocal. Language economizes on words by giving them several different meanings, which the fluent listener or reader can distinguish in context. Equivocations are the raw materials for puns. There is always at least one semantical rule for the meaning complex for each univocal use of a descriptive term, because to be meaningful, the term must be part of the linguistic system of beliefs. If the use is conventional, it must be capable of a lexical entry in a dictionary, or else recognized by some clique as an argot.
A descriptive term’s use is univocal, if no universally quantified negative categorical statement accepted as true can relate any of the predicates in the several universal affirmations functioning as semantical rules for the same subject term. Thus if two semantical rules have the form “Every X is A” and “Every X is B”, and if it is also believed that “No A is B”, then the terms “A” and “B” symbolize parts of different meanings for the term “X”, and “X” is equivocal. Otherwise “A” and “B” symbolize different parts of the same meaning complex associated with the univocal term “X”.
A definition in a unilingual dictionary functions as a semantical rule. But the dictionary definition is only a minimal description of the meaning complex of a univocal descriptive term, and it is not the whole description. Univocal terms have many semantical rules, when many characteristics can be predicated universally to a given subject. Thus there are multiple predicates that universally characterize ravens, characteristics known to the ornithologist, and which may fill a paragraph or more in his ornithological reference book.
Descriptive terms can become, as it were, partially equivocal through time, when some parts of the term’s meaning complex are unaffected by a change of defining beliefs, while other parts are simply dropped as archaic or are replaced by new parts contributed by new beliefs. In science this partial equivocation occurs when one theory is replaced by another newer one due to a test outcome, while the test designs for both theories remain the same. A term common to old and new theory may remain univocal only with respect to the parts contributed by the test-design language.
3.26 Signification and Supposition
Supposition
