Predication and rule-following

According to the traditional view, propositions are the primary bearers of truth conditions. We latch onto propositions by entertaining them, and then deploy them in various ways in our thoughts and utterances. The truth conditions of our thoughts and utterances are then derived from the truth conditions of propositions. This raises the question of whether we can explain how propositions themselves have truth conditions, which is one form of the problem of the unity of the proposition. Attempts at solving this problem end in a philosophically unsatisfying account of representation in thought and language, in which propositions and our relations to them are all taken as primitive and sui generis. In my book Propositional Content (Hanks 2015a) I developed a theory that reverses the traditional order of explanation. According to this theory, acts of predication are the primary bearers of truth conditions. Propositions are types of these actions, which derive their truth conditions from their tokens. This puts acts of predication at the heart of the philosophical explanation of representation, content, and truth. Acts of predication are acts in which we sort or categorize objects according to properties. Through their satisfaction conditions, properties provide the correctness conditions for these acts. For example, an act of predicating the property of being blue of an object is correct just in case that object satisfies that property. By providing correctness conditions, properties thus play a crucial role in explaining how acts of predication are capable of being true or false. In this paper I consider two problems for this explanation. The first, which I call the "Stalnaker problem", asks for an explanation of how properties have satisfaction conditions. This is the analog of the unity problem for properties. Solving this problem is relatively straightforward, but it leads to a second, much more difficult problem, which goes to the heart of Wittgenstein's rule-following considerations. These considerations pose serious metaphysical and epistemological problems for a Platonistic conception of rule-following, on which properties provide standards of correctness for acts of predication. I do not currently have an alternative to Platonism. The aim of this paper, then, is to clarify the problems that Wittgenstein's rule-following considerations pose for an act-based theory of predication, and to present some desiderata for a solution.