Few periods are more important in the philosophy of mind than the seventeenth century. The new mechanical picture of the physical world confronted many philosophers with an exciting challenge,- they needed to formulate theories of the mind and its place in nature, which were not only more philosophically defensible but also better adapted to the needs of Christian theology than their traditional Aristotelian-Scholastic rivals. Although many of the theories that were advanced are widely rejected today, there is no doubt that they left a decisive mark on subsequent thinking; indeed, they helped to define the contemporary agenda in the philosophy of mind. For instance, current debates over the merits of dualism and materialism are often clearly of seventeenth-century inspiration. Other thinkers in the period may have had a more direct impact on modern philosophy of mind, but few, if any, are more interesting than Malebranche.