Philosopher, mathematician, librarian, scientist, diplomat, jurist, logician, philologist…just some of the few things Gottfried Wilhelm Leibniz was pretty good at! Leibniz occupies a gigantic place in the world of science and philosophy and for good reason. He invented calculus (independently of Newton), introduced the concept of monad to philosophy, and gave a blueprint for computing, 300 years before the invention of the computer!The philosophy of Leibniz opened new horizons in our perception of nature, human knowledge and the human spirit. His was a philosophy of ideas, which, Leibniz understood as objects of thought, that can be defined as clear, obscure or confused depending on their clarity and their distinction.
What’s God up to?
One of Leibniz’s key contributions was pretty small in ambition- and that was the definition of God!Descartes, the French philosopher had defined God as neither good nor just, but indifferent. God had created the eternal rules of the universe, observable through mechanics and physics. But these rules are arbitrary and had God wished it could have been that 2 +2 make 5 in this arbitrary regime. Hence the world is governed by rules of physics which exist in the manner that an arbitrary nature had created them.For Leibniz, admit such arbitrariness would make God himself arbitrary and hence opposed the geometric nature of Descartes rationality, which he felt was leading him to make such claims. Descartes believed that a physical explanation was essential for everything and such geometric thinking, according to Leibniz would lead to him seeking a mechanical cause for all phenomena. This was of course in line with the science of the times, where physics was able to explain more and more natural phenomena. However, not everything could be explained solely through mechanics. As, the essence of a body is not its dimensions but its force, according to Leibniz.

May The Monad of Force Be With You
For Leibniz, the universe is composed of monads. Monads are simple substances, without parts. One could call them atoms of nature that each have a unity. They are all different. Two individual things cannot be perfectly alike and their difference can only be qualitative, internal, absolute (and not only quantitative). This led to Leibniz proposing the principle of the indistinguishable according to which two real beings always differ by intrinsic characters. There are, and never will be, two strictly alike individuals. Everything is force, everything is soul. Substantial forms are forces which have something analogous to the soul. Everything is force, thought and desire. The world is not a machine.Monads are in infinite number. Unable to begin or end naturally, they can only be created or annihilated. Monads are subject to continual change but, these changes are not by external causes but by an internal principle: the monad is endowed with spontaneity. The quality which gives each monad its individuality is none other than perception. All monads are endowed with perception and each monad perceives the universe from its point of view. The whole universe is reflected in everything in a certain way.

The Fortified City of The Soul
To understand Leibniz’s concept, let’s imagine a fortified city. We can have different points of view depending on where we are. Likewise, substances are all points of view on the universe, all imperfect and partial. In the walled city, only the one who climbs the highest tower sees everything. At the world level, it represents God’s point of view. All substance is perception, but we must not confuse perception and consciousness. Leibniz distinguishes clear perceptions (or apperceptions) from insensitive perceptions, i.e. perceptions that are not conscious of themselves.The difference between the body and the spirit lies in that in the spirit one’s own effort and the external impressions are preserved durably in the memory while in the body these two elements exist only momentarily during the production of the movement. Through this Leibniz tried to explain the idea of body and soul, which the mechanical nature of Descartes philosophy struggled to do.

God the Clock-maker
According to Leibniz, everything happens as if God had created two clocks which he would have set at the same rate, which he would have put in harmony. There is a pre-established harmony: the body regulates itself according to the efficient causes, the souls according to the final causes and there is harmony between these. Which hence explains the harmony with which soul and body co-exist. God created as many substances as possible with the minimum of means. They act on each other but only according to this principle of pre-established harmony. Between the substances there is, in fact, no real influence. They are “windowless” and therefore cannot communicate. Clear perceptions of one monad are answered by confused perceptions of another monad.
Everything is for the best, in the best of all worlds!
Each monad expressing the world in its own way, all the monads harmonizing with each other without communicating, this implies the existence of God. There has to be a central point of view, someone who grants all the monads, who serves as a regulator.To say that things exist by the sole necessity of the divine nature is to reduce the infinity of God. For Leibniz, the world is not necessary but contingent. We must ask this double question: why is there something rather than nothing? Why do things exist this way and not otherwise? The answer to these two questions is not to be found in the consideration of things where each cause refers to another cause ad infinitum, constantly pushing back the problem without solving it. We must therefore conclude that if the world exists, it is because it is created. According to the principle of sufficient reason, that is to say the principle that nothing happens without reason, every element has a cause and it is a necessary being that created contingent things.Posing the idea of a good God, Leibniz concludes that he could only create the best of all possible worlds. This created world is not a perfect world, but the best of all possible worlds. God, as we have said, does not act arbitrarily. He is subject to the laws of reason without which he would not be free. He could not therefore create a contradictory world, even better than ours. Of all the non-contradictory (and therefore possible) worlds he created the best.

Voltaire and Leibniz
Famed French philosopher and writer -Voltaire- was first full of admiration for this theory. In his book, Zadig, he illustrates the optimism of Leibniz by showing that an evil for man can be a good from the point of view of God (point of view which we have said is the only point of view at all). It tells, for example, the story of this child who died in infancy who, if he had lived, would have become a criminal or that of this man whose house is on fire but who will discover a treasure in the charred ruins. Good can come out of evil. Complaints about evil come from the fact that the unfolding of creation is not understood. However, after seeing a terrible earthquake at Lisbon, Voltaire would change his mind and write Candide- a satire on this very theory of Leibniz.
