It is the need to respond to various forms of relativism, with their nihilistic consequences for philosophy and science, that was the primary epistemological goal for Plato and Aristotle. Such a goal is a far more credible and a far more urgent one for them than the refutation of Cartesian radical skepticism, a position they do not even seem to take seriously.
Smith, Robin A., "Foundationalism, Coherentism, and Aristotle" (1992). The Society for Ancient Greek Philosophy Newsletter. 451.