Magnitudes: A Descriptive Metaphysics of Quantity

The primary goal of this dissertation is to develop a novel strategy for doing descriptive metaphysics. I argue that we can obtain substantive metaphysical conclusions by (i) defending a modal epistemology that takes a failed effort to conceive that p to be pro tanto justification for believing that it is impossible that p and (ii) studying the cognitive psychological limits of our mental representation to shed light on the limits of our conceivings. I’ll develop the strategy by using it to draw a conclusion about the metaphysics of quantity — properties that come in fine-grained degrees.