Abstract

Ontology should be conceived as supervenient on scientific theories. They tell us what categories of things there really are. Thus, we would have a unique system of ontology if we would attain the unity of science through a reductionist program. For this, it should be clear how a relation of intertheoretical reduction (with ontological implications) is to be conceived. A formal proposal is laid out in this paper. This allows us also to define the notion of a fundamental theory. Now, it appears that, considering the state of really existing science, the idea of reductionism as based on this explication is highly implausible. However, even if this is the case, the question whether it is possible to build up a unique ontological system remains open. Its resolution depends on the notion of compatibility between fundamental theories, and its application to existing theories and their empirical bases.