Thought: A Journal of Philosophy

Volume 2, Issue 3, September 2013

The Metaphysics of Time and Modality

Comments on ‘De Jure and De Facto Validity in the Logic of Time and Modality

In his paper, Leuenberger (2013) discerns two salient conceptions of logical validity. Strikingly, neither of these conceptions involves modality. He goes on to use these conceptions as a framework to explore certain recent investigations in the logic of modality, where he ingeniously articulates and proves interesting theses about the logic of contingentism. While I think there’s much of interest in Leuenberger’s results, and that his conception of de facto validity gives a unified account of philosophers’ talk of the logic of time and modality, in this note I suggest that perhaps he is too hasty to dismiss the modal conception of validity and that, moreover, his concept of de facto validity may be too inclusive.