The main theses of Malebranche's philosophy are well-known today. The theory of vision in God of ideas, the doctrine of occasionalism, the philosophy of will, the function of intelligible extension, as well as the relationship of Malebranche's thought to Descartes' or Leibniz's have all been carefully studied. Very little work, however, in either France or the United States, has explicitly investigated the status and the function of metaphysics in the work of the Oratorian. The question of the definition and the role of a Malebranchian metaphysics gives rise to two distinct but inseparable lines of investigation.

First, is it legitimate to search for a definition and systematic use of the word métaphysique in Malebranche? This investigation requires us to determine the relation of any possible Malebranchian metaphysics to the history of metaphysics in the classical period. The other issue is whether Malebranche's metaphysics constitutes a new and original figure in the evolution of metaphysics in the seventeenth century. This essay will seek to address these two questions simultaneously.