Towards a non-uniform epistemology of modality

Abstract

While most theories of a modal epistemology implicitly assume, or sometimes explicitly state, a uniform picture of the epistemology of modality, in this thesis I challenge this basic assumption. I argue that there is not one single epistemology of modality for all ‘domains of discourse’. That is, there is no one single way of coming to know modal propositions with such different content as those of mathematics, logic, physics, or the empirical world. I am not attempting to show that all epistemologies of modality should be non-uniform, but instead I am arguing that three influential modal epistemologies each fail to paint a uniform picture of our epistemic access of the modal realm on their own, but taken together form a coherent non-uniform epistemology of modality. The counterfactual theory fails to provide an adequate answer to how we attain modal knowledge of necessary mathematical and empirical propositions. These necessary truths, I argue, do not possess the relevant independence from each other to be analysable in terms of counterfactuals. I argue that Williamson is forced to accept a non-uniform epistemology of modality as a result with respect to our knowledge of constitutive truths. Next, I outline Vetter’s possibility-based epistemology of modality and pose three challenges: the access problem, the problem of scope and the generalization problem. The resulting picture is a firmly non-uniform epistemology of modality on at least the level of an epistemology of circumstantial modality and, similar to the counterfactual-based account, the level of essential truths. In the last chapter of this thesis, I discuss Bob Hale’s essentialist modal epistemology. I take on board the essentialist epistemology of necessity, and focus instead on knowledge of possibility on this account. I argue that, on its own, it fails to paint a psychologically plausible picture of how we come to know obvious modal possibility knowledge but instead may plausibly be complemented by other epistemologies of modality.