道徳的真理・ミニマリズム・非認知主義

抄録

The early non-cognitivists in metaethics used to claim that moral sentences such as “torture is wrong” are neither true nor false, because they are merely expressions of our attitudes or emotions. By contrast, more recent non-cognitivists have come to acknowledge that there are in fact moral truths, i.e., moral sentences that are true. This change of view is often defended by appealing to the so-called minimalist or deflationary theory of truth, according to which “true” is simply an expressive device for agreement or endorsement, so that there is nothing more in saying “S is true” than in saying S itself. With this theory on truth in hand, it becomes surely possible for non-cognitivists to recognize the existence of moral truths, since they can sincerely accept some moral sentences.
　However, in my view this is not an appropriate way for non-cognitivists to accommodate the moral truth. A first difficulty is the problem of “creeping minimalism”, which is to the effect that once non-cognitivists invoke the minimalism about truth, they cannot stop invoking minimalism about other notions （such as belief and fact）, so that they end up collapsing into realism. A second difficulty is that the appeal to the truth minimalism makes it difficult for noncognitivists to admit the legitimacy of constitutive explanations about truth in other domains than ethics. A third difficulty is that the appeal to the truth minimalism makes the significance of explanatory project by quasi-realists hardly intelligible.
　After considering these difficulties, in the final part of the paper I propose an alternative strategy for non-cognitivists. It consists in holding the “functionalism about truth”, according to which truth is a functionally defined and multiply realizable property. By endorsing this view, I argue, non-cognitivists can successfully meet the three difficulties mentioned above, so it is recommended for them to accept it.