existence

In philosophy, what is common to everything that there is. Like being, existence is a fundamental notion in metaphysics generally. Existence can be contrasted with being, as in some types of existentialism; or it can be contrasted with essence, as in the work of Thomas Aquinas.

In medieval and rationalist metaphysics, existence is perfection. The ontological argument - God is perfect; existence is a perfection; therefore, God exists necessarily - turns on whether existence can be a predicate or property, which German philosopher Immanuel Kant denied.