of our warranted belief that the theory belongs or does not belong to genuine science. Only if we thus govern our acceptance of theories can we move towards eliminating prejudice, bias, and unjustified conjecture from the enterprise of theorizing. Foundationalism has been the reigning theory of theories in the West since the high Middle Ages. It can be traced back as far as Aristotle, and since the Middle Ages vast amounts of philosophical thought have been devoted to elaborating and defending it.