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 enables identifying ambiguities not due to differences in signification that make equivocations, but instead are ambiguities due to differences in relating the semantics to its ontology.
The signification of a descriptive term is its meaning, and terms with two or more alternative significations are equivocal in the sense described in Section 3.25. The signification of a univocal term has different suppositions, when it describes ontology differently due to its having different functions in the sentences containing it.
Historically the subject term in the categorical proposition is said to be in “personal” supposition, because it references individual entities, while the predicate term is said to be in “simple” supposition, because the predicate signifies attributes without referencing any individual entities manifesting the attributes. For this reason the predicate in the categorical proposition is not logically quantified with any syncategorematic terms such as “every” or “some”. For example in “Every raven is black” the subject term “raven” is in personal supposition, while the predicate “black” is in simple supposition. So too for “No raven is black”.
Unlike semantical rules that describe signification, the supposition of descriptive terms in object language depends only on the rôle of the terms in a statement containing them and not on the truth of the statement. Thus the suppositions of the subject and predicate terms respectively are the same in the statement “Every raven is orange”, which is believed to be false, as they are in the statement “Every raven is black”, which is believed to be true.
Both personal and simple suppositions are types of “real” supposition, because they are different ways of talking about extramental reality. They operate in expressions in object language and thus describe ontologies as either attributes or the referenced individuals characterized by the signified attributes. Real supposition is contrasted with “logical” supposition, in which the meaning of the term is referenced in the metalinguistic perspective exclusively as a meaning, i.e., only semantics is referenced and not extramental ontology. For example in “Blackness is a component part of the meaning of raven”, the terms “raven” and “blackness” in this statement are in logical supposition. Similarly to say in explicit metalanguage “‘Every raven is black’ is a semantical rule” to express “Black is a component part of the meaning of raven”, is again to use both “raven” and “black” in logical supposition.
Furthermore just to use “Every raven is black” as a semantical rule in order to exhibit its meaning composition without actually saying that it is a semantical rule, is also to use the sentence in the metalinguistic perspective and in logical supposition. The difference between real and logical supposition in such use of a sentence is not exhibited syntactically, but is pragmatic and depends on the intention of the writer or speaker. Whenever a universally quantified affirmation is used in the metalinguistic perspective as a semantical rule for analysis in the semantical dimension, both the subject and predicate terms are in logical supposition. Lexical entries in dictionaries are in the metalinguistic perspective and in logical supposition, because they are about language and are intended to describe meanings.
In all the above types of supposition the same univocal term has the same signification. But another type of so-called supposition proposed incorrectly in ancient times is “material supposition”, in which the term is referenced in metalanguage as a linguistic symbol in the syntactical dimension with no reference to a term’s semantics or ontology in object language. An example is “’Raven’ is a five-letter word”. In this example “raven” does not refer either to the individual real bird or to its characteristics as in real supposition or to the universal concept of it as in logical supposition. Thus material supposition is not supposition properly so called, because the signification is different. It is actually an alternative meaning and thus a type of semantical equivocation. Some philosophers have used other vocabularies for recognizing this equivocation: Stanislaw Lesńiewski’s “use” (semantics) vs “mention” (syntax) and Rudolf Carnap’s “material mode” (semantics) vs “formal mode” (syntax).
3.27 Aside on Metaphor
A metaphor is a predication to a subject term that is intended to include only selected parts of the meaning complex conventionally associated with the predicate term, so the metaphorical predication is a true statement due to the exclusion of the remaining parts in the predicate’s meaning complex that would make the metaphorical predication a false statement.
In the last-gasp days of decadent neopositivism some positivist philosophers invoked the idea of metaphor to explain the semantics of theoretical terms. And a few were closet Cartesians who used it in the charade of justifying realism for theoretical terms. The theoretical term was the positivists’ favorite hobbyhorse. But both realism and the semantics of theories are unproblematic for contemporary pragmatists. In his “Posits and Reality” Quine said that all language is empirically underdetermined, and that the only difference between positing microphysical entities (like electrons) and macrophysical entities (like elephants) is that the statements describing the former are more empirically underdetermined than those describing the latter. Thus contrary to the neopositivists the pragmatists admit no qualitative dichotomy between the positivists so-called observation terms and their so-called theoretical terms.
As science and technology advance, concepts of microphysical entities like electrons are made less empirically underdetermined, as occurred for example with the development of the Wilson cloud chamber. While contemporary pragmatist philosophers of science recognize no need to explain so-called theoretical terms by metaphor or otherwise, metaphor is nevertheless a linguistic phenomenon often involving semantical change and it can easily be analyzed and explained with componential semantics.
It has been said that metaphors are both true and false. In a speaker or writer’s conventional or “literal” linguistic usage the entire conventional meaning complex associated with a univocal predicate term of a universal affirmation is operative. But in a speaker or writer’s metaphorical linguistic usage only some selected component part or parts of the entire meaning complex associated with the univocal predicate term are operative, and the remaining parts of the meaning complex are intended to be excluded, i.e., suspended from consideration and ignored. If the excluded parts were included, then the metaphorical statement would indeed be false. But the speaker or writer implicitly expects the hearer or reader to recognize and suspend from consideration the excluded parts of the predicate’s conventional semantics, while the speaker or writer uses the component part that he has selected for describing the subject truly.
Consider