Rationalism

Malebranche's philosophical system is a synthesis of Cartesian philosophy and Augustinian theology. In The Search after Truth, Malebranche seeks to remedy human ignorance by presenting the nature of the human mind and showing that it is only by heeding the perceptions of the pure intellect that human beings may achieve knowledge. In the course of elaborating this view, Malebranche develops his two most distinctive doctrines: the vision in God and occasionalism.

The vision in God is Malebranche's account of human knowledge of truths about the world. He claims that human beings may cognize general truths because they have access to those truths in God's mind; they must have access to truths in God's mind because general truths are eternal and infinite and therefore could not be contained in the finite human mind. Occasionalism is a general account of causation, according to which no finite being (whether a mind or a body) is the real cause of any change in the world. Malebranche maintains that a real causal connection must be one that is necessary; however, there is a necessary connection only between God's will and some effect. Consequently, apparent causes are merely occasions for the exercise of God's causal power in accordance with the natural laws constitutive of nature.

In the Treatise on Nature and on Grace, Malebranche deploys these doctrines in order to explain God's action in the created world. He seeks to show that the seeming imperfection of the natural world manifest in natural disasters and the birth of monsters, and the apparent inequality in God's distribution of grace, are merely apparent defects. Because God acts in accordance with general laws, and does not intervene directly to produce particular events, his action in the realms of nature and grace is essentially limited. Malebranche believes that God must act in accordance with general laws because if he were to intervene at every moment in the world, he would not act in accordance with his own nature. Moreover, the world would thereby cease to be intelligible to human beings. Occasionalism, consequently, guarantees the intelligible order of the universe.