Abstract

Like scientific theories, metaphysical theories can and should be justified by the inference of creative abduction. Two rationality conditions are proposed that distinguish scientific from speculative abductions: achievement of unification and independent testability. Particularly important in science is common cause abduction. The justification of metaphysical realism is structurally similar to scientific abductions: external objects are justified as common causes of perceptual experiences. While the reliability of common cause abduction is entailed by a principle of causality, the latter principle has an abductive justification based on statistical phenomena.