Abstract

In recent years, there have been surges of interest in constitutive explanation. This kind of explanation is distinct from a causal explanation. For example, “Jack is evil because he killed a lot of people” is a constitutive explanation. In this case, the explanans does not cause the explanandum, but instead, constitutes the explanandum. Metaphysicians refer to this kind of explanation as “ground” and study its logical features and connections with other notions. The purpose of this paper is to review the recent studies on the logical features of ground. These studies typically aim to construct the logic of ground, and this paper surveys its proof theory. With this, the following questions will be explored. What logical features does ground have? What are logically complex propositions grounded in? What do logically complex propositions ground? Examining these three questions, we can distinguish between the pure logic and the impure logic of ground. The former concerns the first question, and the latter concerns the second and third questions. With few exceptions, philosophers agree with the pure logic of ground. However, controversies arise in the impure logic of ground, and many philosophers have proposed different systems. Moreover, these systems differ concerning the rules that determine the logical behavior of ground. It is important because such differences imply significant distinctions in philosophical conceptions of ground. Finally, the notion of “ground-theoretic equivalence, ” a central theme of this paper, has an important role in contouring the differences.