Daniel Warren

Kant regards matter as not only extended but impenetrable. However, Kant distinguishes two senses of impenetrability: mechanical and chemical. Kant accepts the former as necessarily belonging to matter, but he denies, or at least sees no reason to accept, the latter. The kind of chemical penetration that Kant is concerned with occurs when no part of the one component matter exists unmixed with the other matter. Here, the two component matters come to fill the whole of the very same space. Kant distinguishes two kinds of process that can lead to such penetration: cases of “literal” dissolution of one matter (a solute) through being broken up by the other (the solvent), in which the former is divided into parts ad infinitum; and cases where the one matter simply progressively permeates the other. Kant considers problems associated with the former that he does not regard as at issue in the latter.