Summary: Monadology (page 3)

God chose the universe in which the relations between the monads are as perfect as possible. This harmonious connection of each monad with all the others means that each has relations that reflect them all, becoming a perpetual living mirror of the universe ¹. Leibniz praises this universal harmony, which makes every substance accurately reflect all the others through its relations with them ².

If God is a necessary substance, all other beings are contingent. This does not mean that they arise and act arbitrarily; on the contrary, there is always a sufficient reason for their actions and for every event. They are contingent in the sense that the ground of their existence lies outside themselves, whereas God's sufficient reason lies within himself; moreover, he is the sufficient reason for everything.

Nothing happens by chance; Leibniz's doctrine is marked by a profound determinism. So much so that anyone who could fully grasp the present moment would be able to deduce both the past and the future from it.

Since bodies affect one another in an endless chain of interactions, each body is, in a sense, connected to everything that happens in the universe, so much so that a being who sees everything could read, in each body, what is happening everywhere and even what has happened or will happen, perceiving in the present what is distant in both time and space ³.

The monad represents the entelechy, or soul, of the body to which it belongs.

Each body is comparable to a natural automaton, yet infinitely superior to artificial automata: The machines of nature [or natural automata]—that is, living bodies—are still machines down to their infinitely small parts ⁴.

Matter is infinitely divisible, implying that there is a world of creatures, souls, and entelechies in the smallest portion of matter ⁵.

As a result, each portion of matter can be imagined as a garden full of plants or a pond full of fish. Moreover, every branch of a plant, every limb of an animal, and every drop of its fluids remains such a garden or pond ⁶.

The body does not act upon the soul, nor does the soul act upon the body. Instead, they exist in pre-established harmony, ensuring that the decisions of the mind coincide with the movements of the body:

The soul follows its own laws, just as the body follows its own; yet they correspond perfectly, thanks to the pre-established harmony between all substances ⁷.

More precisely, souls act according to the laws of final causes. Bodies act according to the laws of efficient causes. And the two realms—that of efficient causes and that of final causes—are perfectly harmonious with each other ⁸.

The famous Leibnizian notion of pre-established harmony offers an original solution to the problem of the union of soul and body—namely, how the mind can act on the body when it is immaterial—already examined by Descartes in the Passions of the Soul and by Spinoza in the Ethics.

The totality of spirits forms the City of God—namely, the most perfect possible state under the rule of the most wise and just monarch ⁹.

Leibniz concludes by once again affirming that this world is the best of all possible worlds—a claim that would later provoke a biting retort from Voltaire in Candide:

If we could fully grasp the order of the universe, we would find that it surpasses the highest hopes of the wisest minds, and that it is impossible to improve it in any way ¹⁰.

¹ 56
² 59
³ 61
⁴ 64
⁵ 66
⁶ 67
⁷ 78
⁸ 79
⁹ 85
¹⁰ 90