In ancient times, the main approaches to metaphysical realism were intuitive. In modern times, foundationalism has replaced intuition as the main strategy to make out metaphysical realist claims to know. In On Foundationalism, Rockmore argues that foundationalism fails in all its known variants. Furthermore, Rockmore argues that Kant plays a crucial role in this regard. Kant's complex position is both foundationalist and anti-foundationalist, committed to metaphysical realism, and also, through its commitment to empirical realism, opposed to metaphysical realism. Before Kant, it made eminent sense to be committed to eventually making out a claim for metaphysical realism by formulating an acceptable version of foundationalism. After Kant, it no longer makes sense even to try to do so.