Published online by Cambridge University Press: 01 January 2020
At the one extreme stands Hume, who -at least according to common conceptions - rules out entirely the possibility of material or non-logical necessity, and who therefore rules out also the possibility that we might enjoy that sort of certain knowledge that earlier philosophers had assumed as a matter of course to be correlated therewith. At the other extreme stands Adolf Reinach, the hero of our present story, who defends the existence of a wide class of material necessities falling within the domain of what can be a priori known. More precisely, Reinach holds that there are certain categories of entity whose factual instantiation brings with it as a matter of necessity the instantiation of certain other correlated categories. The instantiation of the category color necessitates in this fashion the instantiation of the category visual extension.
My thanks are due to Johannes Brandl, Patricia Donohue, and Philip Hanson for helpful comments on an earlier version of this paper.