On Justification Conditional Models of Linguistic Competence

In 'What Dummett Says About Truth and Linguistic Competence', Richard Kirkham distinguishes a number of interpretations of Dummett's views on truth and meaning. After providing evidence that various interpreters have misunderstood Dummett, Kirkham lays out one of Dummett's arguments for the conclusion that truth conditional theories of meaning are without content, which supports the thesis that truth does not play a fundamental role in the theory of meaning. Finally, Kirkham attempts to refute Dummett's argument by offering a counter-example to the crucial premiss that the behaviour of competent speakers can be explained by appeal to implicit knowledge of justification conditions, without also attributing to them implicit knowledge of truth conditions distinct form justification conditions. I shall not address the issue of accuracy of interpretation or representation of Dummett's views. What I shall argue is that Kirkham's proposed counter-example does not succeed. Drawing on an example offered by Crispin Wright, Kirkham considers a speaker suffering from a congenital lack of a sense of taste. For such a person propositions like 'this is sweet' and 'this is salty' are undecidable, since there are circumstances in which she cannot ascertain their truth-values. Still, she knows justification conditions for such propositions, conditions largely in terms of the behaviour of the unafflicted when dealing with stuff that is sweet or salty. Wright also allows her the ability to discern relations of logical consequence between various attributions of taste to a substance (such as Kirkham's example, that 'this is salty or sweet' and 'this is not salty' entails 'this is sweet'), an ability which he thinks can be accounted for on the basis of her knowledge of justification conditions. Kirkham admits that this ability can be explained on a justification conditional model of meaning and lingusitic competence by use of an intuitionist/constructivist redefinition of 'logical consequence' in terms of justification conditions: X is a logical consequence of Y if and only if it is impossible for X not to be justified if Y iS (p. 221). (Hereinafter I adopt Kirham's convention of using double quotations to indicate this use of the expression, to distinguish it from the classically defined sense, for which no quotation marks are used.) However, although our tasteless person might assert