In this chapter I examine Robert Brandom’s contribution to the understanding of practical reasoning. More precisely, my question will be: Does an inferentialist explanation of content and reasoning shed new light on the features of practical reasoning in highly institutionalized contexts such as law?
Generally speaking, a theory of practical reasoning is a theory of how to figure out what to do. As a result, a theory of this sort usually focuses on the question of what inference patterns are legitimate methods of arriving at practical evaluations, intentions, plans, and judgments about what one ought to do. In the current philosophical debate, most scholars assume that these inference paths are composed by reasons for action having common characteristics. According to internalism, for instance, reasons for action are the expression of beliefs, desires or other psychological pro-attitudes. On the contrary, externalism maintains that reasons for action are normative properties of facts, which are agent-neutral and apply to individuals independent of their mental states. In this sense, both internalism and externalism assume that practical reasoning requires a foundation demarcated in some ontological fashion, which identifies the essential properties of reasons for action. In this way, both approaches provide a unitary picture of practical reasoning, i.e. a “one-system view” about how we can come to know or justify what we ought to do.
I will show that Brandom’s inferentialism yields a deflationary account of reasoning, in which the theory of practical reasoning boils down to a theory of argumentation. Practical reasoning is conceived by Brandom as an exchange of reasons within an argumentative practice which determines the conditions under which practical judgements are justified. Therefore, there can be indefinitely many different kinds of legitimate practical inference, depending on the game of “giving and asking for reasons” one is engaged in. The unity practical reasoning is given by the pragmatic process in virtue of which practical judgments, evaluations and plans are socially elaborated. In highly institutionalized contexts such as law, this pragmatic process is characterized by a set of constitutive rules (entry-rules, exit-rules, and structural rules) which establish the normative status of the participants in an exchange of reasons, govern the way in which the argumentative practice takes place, and determine the authoritative character of its outcomes. Consequently, practical reasoning is highly pluralistic in the law, and its inferential structure is internally established by legal practice itself.