The German philosopher Gottfried Leibniz, a supporter of the new mathematical corpuscular physics that flourished during the latter seventeenth century, came to the conclusion that the notion of substance provided essential metaphysical underpinning for a complete understanding of reality.
Leibniz proposed that the universe is of made up of "simple substances" which he designated as "Monads. " The Monad is similar to Democritus' concept of the "atom". Monads were indivisible and constantly active particles. Interestingly, Leibniz proposed that monads are more psychological entities, which in human beings are called "souls."
Each Monad is an isolated entity existing on its own in that no Monad interacts with others and that all that constitutes the Monad is contained within the Monad itself. Consequently, everything that happens does so because it necessarily must act in that fashion. The epistemologic implications of this contention lay in the consequent deduction that since the predicate is contained by definition in the subject, therefore, every truth is a necessary truth.
This is true because God has predetermined that this be the case. Had Got predetermined that a truth be otherwise it would have been so. This in turn leads to Leibniz's concept of the "best of all possible worlds" in which reality would have been otherwise if God would have thought it better to be so.
Utilizing the Ontological Argument, Leibniz understood God as a "necessary being" and in essence, for Leibniz, God is the original simple substance from which all Monads emerge, created and uncreated. God is the divine architect of the universe and the universe works with a machine like precision.
