Imagination, Conceptual Possibility & Modal Knowledge; a Critique of the Ichikawa & Jarvis's Model for acquiring modal knowledge

In this paper I will examine Ichikawa & Jarvis’s model (2011) as an imagination-based model for the explanation of acquiring modal knowledge (or possibility of such knowledge). After defining coherent imagination, Ichikawa & Jarvis claim that while we cannot find out about metaphysical possibility with imagination, we can reach another kind of possibility, i.e. conceptual possibility. To explain which proposition is conceptually possible, they use the notion of “conceptual entailment”; a proposition is conceptually possible if it doesn’t conceptually entail an absurdity. Ichikawa & Jarvis show that conceptual possibility and coherent imagination is coextensive, so if we can coherently imagine a proposition, it is conceptually possible. Ichikawa & Jarvis, then, propose a model for the relation between conceptual and metaphysical modality: If proposition P conceptually entails that a proposition, which is not in fact true, is true in the actual world, then P is metaphysically impossible. In this paper after presenting Ichikawa & Jarvis’s model, I will argue that their model is incaple of providing an explanation for acquiring modal knowledge (or possibility of such knowledge) by imagination.