Jonathan Ichikawa

How do we know what's (metaphysically) possible and impossible? Arguments from Kripke and Putnam suggest that possibility is not merely a matter of (coherent) conceivability/imaginability. For example, we can coherently imagine that Hesperus and Phosphorus are distinct objects even though they are not possibly distinct. Despite this apparent problem, we suggest, nevertheless, that imagination plays an important role in an adequate modal epistemology. When we discover what is possible or what is impossible, we generally exploit important connections between what is possible and what we can coherently imagine. We can often come to knowledge of metaphysical modality a priori

I argue that evaluating the knowledge norm of practical reasoning is less straightforward than is often assumed in the literature. In particular, cases in which knowledge is intuitively present, but action is intuitively epistemically unwarranted, provide no traction against the knowledge norm. The knowledge norm indicates what it is appropriately to hold a particular content as a reason for action; it does not provide a theory of what reasons are sufficient for what actions. Absent a general theory about what sorts of reasons, if genuinely held, would be sufficient to justify actions—a question about which the knowledge norm is silent—many of the kinds of cases prevalent in the literature do not bear on the knowledge norm.

In “Against Arguments from Reference” (Mallon et al., 2009), Ron Mallon, Edouard Machery, Shaun Nichols, and Stephen Stich (hereafter, MMNS) argue that recent experiments concerning reference undermine various philosophical arguments that presuppose the correctness of the causal-historical theory of reference. We will argue three things in reply. First, the experiments in question—concerning Kripke’s Gödel/Schmidt example—don’t really speak to the dispute between descriptivism and the causal-historical theory; though the two theories are empirically testable, we need to look at quite different data than MMNS do to decide between them. Second, the Gödel/Schmidt example plays a different, and much smaller, role in Kripke’s argument for the causal-historical theory than MMNS assume. Finally, and relatedly, even if Kripke is wrong about the Gödel/Schmidt example—indeed, even if the causal-historical theory is not the correct theory of names for some human languages—that does not, contrary to MMNS’s claim, undermine uses of the causalhistorical theory in philosophical research projects.