Markos Valaris

In ‘Reasoning and Regress’ I argued that inferring a conclusion from a set of propositions may simply consist in taking it that the conclusion follows from these propositions—thereby defusing familiar regress arguments. Sinan Dogramaci challenges the generality of this view, on the grounds that sometimes you may draw conclusions from no premisses that you believe. I respond by clarifying a distinction between the premisses of an argument from the reasons your conclusion is based upon. While suppositional reasoning may involve no premisses in the former sense, it does not follow that it does not involve concluding something on the basis of reasons. This allows the view defended in ‘Reasoning and Regress’ to extend to suppositional reasoning.

Famously, David Lewis argued that we can avoid the apparent paradoxes of time travel by introducing a notion of personal time, which by and large follows the causal flow of the time traveler's life history. This paper argues that a related approach can be adapted for use by three-dimensionalists in response to Ted Sider's claim that three-dimensionalism is inconsistent with time travel. In contrast to Lewis (and others who follow him on this point), however, this paper argues that the order of events captured by so-called "personal time" should be thought of as causal, rather than temporal.

There is reason to expect a reasonable account of a priori knowledge to be linked with an account of the nature of conceptual thought. Recent “two-dimensionalist” accounts of conceptual thought propose an extremely direct connection between the two: on such views, being in a position to know a priori a large number of non-trivial propositions is a necessary condition of concept-possession. In this paper I criticize this view, by arguing that it requires an implausibly internalist and intellectualist conception of capacities we bring to bear in applying concepts in experience. Empirical concept-application depends on the exercise of a variety of capacities, many of which can be grouped together under the general label “recognitional”. As I argue, two-dimensionalism cannot accommodate a plausible account of such capacities. This suggests that the link between a priori knowledge and the nature of conceptual thought is not as direct as twodimensionalists take it to be. I close by briefly sketching a different way to think of that link.