Mark Greenberg

Tyler Burge’s influential arguments have convinced most philosophers that a thinker can have a thought involving a particular concept without fully grasping or having mastery of that concept. In Burge’s (1979) famous example, a thinker who lacks mastery of the concept of arthritis nonetheless has thoughts involving that concept. It is generally supposed, however, that this phenomenon – incomplete understanding, for short – does not require us to reconsider in a fundamental way what it is for a thought to involve a particular concept. In this paper, I argue that the real significance of incomplete understanding has not been appreciated. To the extent that theorists of content address the phenomenon of thoughts involving incompletely grasped contents at all, they tend to assume that some hand-waving about deference to other thinkers who fully grasp the relevant concepts will take care of the inconvenient cases of incomplete understanding. The main lesson of Burge’s arguments is often taken to be that the content of language and thought is socially determined. On this picture, we do not need to change our basic view about what it is to have a concept; we just need to recognize that some thinkers can manage to have a concept by piggybacking on others. In contrast, on the view I defend, taking incomplete understanding seriously forces us to rethink some of our most basic assumptions about the nature of mental content. Deference is a red herring. The role of society in determining the content of thought is not the main lesson, but at most a useful clue as to the nature of mental and linguistic content.

In this paper, I propose a new way of understanding the space of possibilities in the field of mental content. The resulting map assigns separate locations to theories of content that have generally been lumped together on the more traditional map. Conversely, it clusters together some theories of content that have typically been regarded as occupying opposite poles. I make my points concrete by developing a taxonomy of theories of mental content, but the main points of the paper concern not merely how to classify, but how to understand, the theories. Also, though the paper takes theories of mental content as a case study, much of the discussion is applicable to theories of other phenomena. To a first approximation, the difference between the traditional and the proposed taxonomies turns on whether we classify theories of content by, on the one hand, their implications for a non-redundant supervenience base for content facts (i.e., for facts about what contents thoughts have) or, on the other, by their constitutive accounts of content. By a "constitutive account," I mean the kind of elucidation of the nature of a phenomenon that theorists have tried to give for, for example, knowledge, justice, personal identity, consciousness, convention, heat, and limit. The tendency to taxonomize by supervenience base is encouraged, I suggest, by a failure to keep clearly in view a distinction between constitutive and modal determination. Many philosophers would accept that a constitutive account cannot be captured in purely modal terms. Giving a constitutive account is not the same as specifying modally necessary and sufficient conditions. Nevertheless, philosophers often try to cash constitutive claims in modal terms. A case in point is that theories of content tend to be conceptualized in terms of the theories' implications for a supervenience base for content facts. My thesis goes beyond the by-now somewhat familiar proposition that not all modal determinants of a phenomenon are constitutive determinants. One who has taken that point on board might nevertheless conceive of a philosophical account as an attempt to specify constitutive determinants of the target phenomenon that make up a non-redundant supervenience base for the phenomenon. Shoehorning a philosophical account into this form leaves out elements that are modally redundant, but may be explanatorily or ontologically significant. For example, when a constitutive account has multiple levels, the different levels will typically be modally redundant. Formulating the account as a specification of a supervenience base of constitutive determinants will therefore flatten the account into a single level. Many of my arguments can be illustrated by considering the place of normativity in the theory of content. The new taxonomy gives a distinct niche to normative theories of content - theories that explain a thought's having a certain content at least in part in terms of the obtaining of normative facts. By contrast, on a traditional map, normative theories are invisible as such because normative facts supervene on non-normative ones.