The danger of arbitrary definition

 

The idea that definition be arbitrary

 

[after (!) adequacy and polysemization]

 

In the last century, a certain kind of attitide became fashionable, according to which the definition of terms is largely or completely a matter of free and arbitrary decision. (In a moderate variant, the idea was already present, for example, in the logic of Port Royal; see Arnauld & Nicole 1993 [1683], 60.)

 

This view is mistaken, and it is extremely noxious.

 

It became very popular in the second half of the last century. One of its most prominent proponents is David Lewis. Here is, for example, how Lewis represents the matter with reference to the notion of "truth":

 

I see no problem in letting non-declaratives have the truth-values of the performatives they paraphrase; after all, we need not ever mention their truth-values if we would rather not. (Lewis 1970, 59)

 

Lewis' proposal amounts to an arbitrary re-definition of the term " true". As he frankly admits, the predicate "true" is not applicable to non-declarative sentences (e.g., interrogative and directive sentences). He suggest re-defining it accordingly nevertheless. "I see no problem", he confesses, not to do so.

 

Yet in fact there are certain logical reasons not to re-define a term, and extremely important ones at that. The arbitrary re-definition of a scholarly term is a serious definitional mistake, unless it is required by extremely strong reasons (which Lewis apparently does not have). Why is arbitrary re-definition a mistake?

 

As we said above, in scholarly discourse, definition succumbs to certain logical restrictions; prominent among them is the demand for 'adequacy' (see there). You should not alter the meaning of a term, because this leads to several problems. If you re-define a central term, then either your re-definition is being ignored by others, or it is established at least partially. In the former case, your re-definition was ineffective; in the latter acse, the term you re-defined becomes ambiguous. One typical consequence of this is misinterpretation, confusion, and fruitless debates. Another typical sequel is that the term becomes vague or obscure, which again leads to misinterpretation, confusion and fruitless debates, if the term continues to be used.

 

So I contend that the re-definition of a term leads to misinterpretation, confusion, and fruitless debates. But is this actually true? Should we not rather expect professional philosophers, or at least the more renowned among them, to be cable to keep different notions apart, to keep track of terminological traps, to answer wich accurate reading and minutious clarification? 

 

Well, this question is directed to the facts. It makes no sense to try to answer it from the armchair: it requires us to look at the facts.

 

Here are the facts. In the following cases are introduced where some of the most distinguished philosophers earth had the honour to bear do make the most serious of mistakes, due to the fact that one or the other central philosophical term was re-defined--and they were actually not able to keep track of the complexities arising.

 

Example 1: Lewis 1970, arbitrary re-definition of "true", causes invalid argument

In order to be able to say that non-declarative sentences (e.g., interrogative sentences, directive sentences) be "true", Lewis introduces a peculiar definition of the predicate "true", which is not in accordance with the real meaning of that word (a sentence is "true" in this peculiar sense when a certain kind of putative paraphrase of that sentence is true--in the normal sense of that word). Let us refer to Lewis' peculiar conception as"truthLEWIS". It is clearly inadequate: it does not conform to any common usage of the word "true".

Lewis introduces his peculiar definition in order to save the general assumption that all sentences have truth conditions. Against this view, it may be objected that non-declarative sentences (interrogative, directive sentences) cannot be true or false, and hence do not have any conditions of their truth.

Lewis' argument says, roughly, that since all sentences, even non-declarative ones, are trueLEWIS under certain conditions, all sentences have truth conditions, such that the objection which seems to threaten the truth-conditional approach fails.

However, Lewis' argument is fallacious, eventually due to the mistake of re-defining a term without regarding the requirement of adequacy.

Given that truthLEWIS is not truth (in the ordinary sense), the possibility of truthLEWIS does not imply the possibility of truth (in the ordinary sense). Due to the homonymy between the two notions, Lewis confuses them. His argument, being based on the mistaken equation, is invalid. For a more detailed exposition click here. 

 

Example (2): Frege 1892, inadvertent re-definition of "Bedeutung", causes the gratuitous discussion of a theory he never proposed

Frege defines the term "Bedeutung" ("meaning"), which actually refers to an expression's meaning, expression, as applying to an expression's reference (extension). Thus, in his terminology, the planet Venus is being called the "meaning" of the words "morning star". This definition is clearly inadequate, since it does not conform to any common usage of the word "Bedeutung", which really applies, not to an expression's reference (extension), but to an expression's meaning (intention). In effect, this definition amounts to a re-definition of the word "Bedeutung", which made the term ambiguous (within the philosophical debate).

Due to Freges terminological extravagance, many interpreters mistakenly believed (and some still believe today) that Frege proposes an account of meaning, according to which the meaning of an expression is its extension--an extensional account of (or approach to) meaning. In fact, however, Frege never proposed such an account. In Frege's terminology, the meaning of an expression is called its "Sinn"; and Frege's conception of "Sinn" is intensional. Thus, Frege adheres to an intensional conception of meaning.

So Frege's (unplanned) re-definition of the word "Bedeutung", which caused an intension/extension ambiguuity of that word, led to a confusion of his account of the extension of an expression with an account of the meaning of an expression. One author who fell for that ambiguity is Donald Davidson, in his paper "Meaning and Truth" (1967). There, he analyses at length and in great detail the prospects of a certain 'extensional theory of meaning', before, motivated by the failure of this theory, he turns over to his own preferred approach. That extensional theory of meaning, however, is nothing but Frege's theory of an expression's extension--which, quite obviously, Davidson mistakes for a theory of meaning. Thus, due to the ambiguity of the term "Bedeutung", which Frege caused by his (unintentional) re-definition of that term, Davidson engages at length in the discussion of a theory which was really never proposed. For a more detailed exposition click here [link is still blind].

 

Example (3) Quine 1951, inadvertent re-definition of Kant's term "analytic"; corrupts this term

 

(1.a) SEP: An “analytic” sentence, such as “Ophthalmologists are doctors,” has historically been characterized as one whose truth depends upon the meanings of its constituent terms (and how they’re combined) alone, as opposed to a more usual “synthetic” sentence, such as “Ophthalmologists are rich,” whose truth depends also upon the facts about the world that the sentence represents, e.g., that ophthalmologists are rich.

(1.b) Wikipedia: Analytic propositions are true solely by virtue of their meaning, whereas synthetic propositions are true based on how their meaning relates to the world.

 

(2) The term is consistently recognised as introduced by Kant.

 

(3.a) Kant's notion of an "a priori" proposition: "a proposition whose justification does not rely upon experience. Moreover, the proposition can be validated by experience, but is not grounded in experience"

(3.b) Kant's notion of an "analytic" proposition: "a proposition whose predicate concept is contained in its subject concept"

 

Quite apparently, Quine confuses "a-prioricity" with "analyticity"

 

(Quine's fault probably goes back (at least) to Frege, who made the same mistake; however, it seems that the large distribution of the mistake is (more immediately) due to Quine's influence.)

(Wikipedia currently suggests that the logical positivists, and particularly Frege and Carnap deliberately "revised" the Kant's notion (rather than just confused Kant's dichotomies). However, as far as I see, the exposition contains no serious evidence for this view.)

 

For a more detaile exposition of the issue click here. [BLIND LINK]

 

 

 

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?? (x) Searle 198x, B&H 198x, non-identical definition of "performative utterance", causes talk at cross-purposes