Pre-established harmony

Gottfried Leibniz's theory of pre-established harmony (French: harmonie préétablie) is a philosophical theory about causation under which every 'substance' affects only itself, but all the substances (both bodies and minds) in the world nevertheless seem to causally interact with each other because they have been programmed by God in advance to 'harmonize' with each other. Leibniz's term for these substances was 'monads' which he described in a popular work (Monadology §7) as 'windowless'. Gottfried Leibniz's theory of pre-established harmony (French: harmonie préétablie) is a philosophical theory about causation under which every 'substance' affects only itself, but all the substances (both bodies and minds) in the world nevertheless seem to causally interact with each other because they have been programmed by God in advance to 'harmonize' with each other. Leibniz's term for these substances was 'monads' which he described in a popular work (Monadology §7) as 'windowless'. Leibniz's theory is best known as a solution to the mind–body problem of how mind can interact with the body. Leibniz rejected the idea of physical bodies affecting each other, and explained all physical causation in this way.