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 , 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.