According to Leibniz, what was set up by God at the beginning of the universe?

Leibniz proposed the concept of monads as simple, indivisible substances that form the fundamental building blocks of reality. According to his philosophy, God established a pre-established harmony at the beginning of the universe, which ensures that all monads operate in coordination with one another, even though they do not interact directly. This means that each monad reflects the entire universe from its own unique perspective, operating independently but in synchrony with all others, which thus maintains a harmonious existence without direct interaction.

This notion is foundational in Leibniz's metaphysics, as it explains how a diverse and complex universe can emerge from simple, unchanging units without chaotic interactions. The idea of a pre-established plan highlights the belief that there is an underlying order and purpose to the universe, orchestrated by God, which is essential in understanding Leibniz's philosophical system.