Monadology

Monadology is a concise 1714 philosophical treatise by Gottfried Wilhelm Leibniz that presents his mature ontology in the form of 90 short propositions. It outlines the theory of monads, the fundamental substances that make up reality.

Monads are simple, indivisible, and immaterial entities. They have no physical extension and cannot interact causally with one another. Instead, each monad contains a unique, internal representation of the entire universe, and its state changes according to an internal principle. The order of these changes is coordinated by a pre-established harmony arranged by God, so the apparently coordinated phenomena of different monads correspond without direct contact.

Perception and consciousness play central roles. Monads vary in degree of awareness: some possess clear perceptions, others only faint ones; humans possess self-conscious perception, or apperception, and memory. The term petite perceptions refers to small, ordinary internal states that, collectively, form more complex perceptions.

Space and time, for Leibniz, are not absolute features of the external world but orders of the relations among monads and their perceptions. The universe, therefore, is a continuum of monads unfolding in concert under divine governance.

God is the supreme monad and the ultimate source of order, whose perspective encompasses all other monads. The Monadology is often read as a compact articulation of Leibniz’s broader metaphysical program, contrasted with mechanical explanations of nature and connected to his other writings on substance, perception, and harmony.