Occasionalism

Occasionalism is the metaphysical theory, associated primarily with Nicolas Malebranche (1638–1715), that holds that apparent causal interactions between mind and body (and more broadly between any two finite substances) are not genuine causal relations but rather occasions for God to directly cause the correlated effects. When I decide to move my arm, it is not my mental intention that causes the arm to move — God, on the occasion of my mental intention, causes the physical movement. Occasionalism arose as a response to the mind-body interaction problem generated by Cartesian dualism: if mind and body are fundamentally different substances with no common properties, how can one cause changes in the other? Malebranche concluded that they cannot — that only God, as the single universal cause, genuinely produces effects. The position solves the causal interaction problem by eliminating finite causation entirely, replacing it with continuous divine intervention. This solution is theologically neat and philosophically extravagant: it requires God to perform an infinite number of correlated miraculous interventions at every moment in the universe. Leibniz's pre-established harmony — God sets up the parallel tracks of mental and physical in advance — is a more parsimonious version of the same basic move, avoiding continuous intervention at the cost of making genuine interaction impossible.