occasionalism

A philosophical theory, associated particularly with Malebranche and Geulincx, which espouses Descartes' dualism of mind and body but tries to explain all causal interaction between them by God's direct intervention. God ‘occasions’ all processes and events, and mind and body operate in a separate but perfectly synchronized way, like two clocks.

Occasionalism is a philosophical theory about causation which says that matter (and often mind) cannot be a true cause of events. Instead, all events are taken to be caused by a supreme power, such as the Schopenhauerian Will, or an Abrahamic God. The theory states that the constant conjunction between causes and effects occurs only because every instance where the cause is present constitutes an occasion for the effect to occur as an expression of the aforementioned power. Thus, a person's mind cannot be the true cause of his hand moving, nor can a physical wound be the true cause of mental anguish - in other words, the mental cannot cause the physical and vice versa. Still, Occasionalists generally also held that the physical cannot cause the physical either - apparently because of arguments similar to those of David Hume and his medieval forerunner Nicholas of Autrecourt, who both said that we cannot perceive any necessary connection between causes and effects. Thus, Occasionalism brings in God to fill this gap, since what God wills is taken to be necessary.

In a strict formulation of Occasionalism, the physical world never has any direct effect on anyone's perceptions. Berkeley maintained that there was no such thing as matter, but merely perceptions, caused in us by God. The ninth century theologian Abu al-Hasan al-Ash'ari defended the notion of an utterly omnipotent God who could will absolutely anything (even that a perfectly good man could be sent to hell), and that nothing can endure for more than one instant without being recreated by God.