Leibniz conceives of the universe as containing nothing but a sea of monads; each monad acts in accordance with the others to produce perceptions of the world as phenomena. Each reflection on the world by a soul is only perceptions of interrelationships between monads. In an effort to contrast his system with the Cartesians who prioritized the mechanism of causality and motion to explain interactions, Leibniz deploys the pre-established harmony to provide a foundation to his interpretation of the cosmos. The perceptions or phenomena within the cosmos unfold in accordance with a pre-programmed routine that is crafted by God. This determined universe is what Leibniz calls the ‘pre-established harmony.’ Pre-established harmony also serves to explain how the metaphysical realm interacts with the physical realm. Although Leibniz generally splits the realms of actuality into metaphysics and physics, he wants to remind us through the explanation of the pre-established harmony that these two realms of metaphysics and physics are not “disparate or disjointed” characteristics of the world (Rescher, 65). Rather than being a dualism, the physical phenomena we perceive are only derivative from the metaphysical interrelation between monads. Thus, if Leibniz wishes to advance the Principle of Sufficient Reason while simultaneously saying that the universe is made up of an infinite number of monads, then he must have a sufficient explanation for their seeming interaction. In this manner the ‘pre-established harmony’ provides a basis for the Leibnizian system.
Leibniz calls this system ‘pre-established’ because its phenomena have been determined anterior to their creation. To understand this fully we must first investigate the role of essence and existence in the Leibnizian system. God has the capacity to imagine infinite possible worlds and therefore choose between an infinity of predications for these worlds. If God were to actualize a particular world, then this world would exhibit perfection. God must begin to understand something as perfection purely in terms of its intrinsic or eternal potential. In short, God prioritizes essence over existence because he is dealing with possible predications that do not exist, at least yet. What is meant by this is that God utilizes foreknowledge to anticipate all the predications or the complete individual notion of a possible substance before that substance comes into existence. Therefore in accordance with God’s choice to actualize this world, this world is also the most perfect of possible worlds. In this sense it is pre-established for perfection based on God’s foreknowledge. God’s choice of perfection coupled with Leibniz’ Principle of Sufficient Reason leads to a universe that proceeds according to reason. The Principle of Sufficient Reason warrants that every unfolding must contain a reason for its subsistence. Thus, the initial will of God to create the perfect universe means that this universe can only progress according to reason. In this picture to alter any single perception would require a re-assembling of monadic connections to the degree that we are no longer speaking of the same universe. By ‘connections’ Leibniz means the manner by which monads relate to other monads to give way to perceptions; this is not to imply a causal operation. In the case of ‘perfection’ Leibniz envisions a special criterion. He says that perfection is defined as the maximization of variety while simultaneously being the “simplest in its hypothesis” (Rescher, 17-18). What Leibniz means by this is that God is inclined to produce a universe that leads to the most ordered richness if he was to produce a universe at all.
The Leibnizian system is also described as a ‘harmony’ in the sense that it is not a causal interaction but rather an interrelation of accordance or “agreement” across monads (Rescher, 66). The universe is made up of an infinite number of continually changing monads. Each monad operates on its own; it is self-complete. What we call an ‘interaction’ is actually just a coincidence that is arranged by the will of God. The example of clocks hanging in a room provides a brief analogy. Within the Newtonian system it is believed that the measurement of time is independent of the clocks themselves. In this depiction the clocks are being synced to something outside of their internal workings. This is to say that we can measure time according to a pre-defined scale existent before the clocks themselves. For Leibniz this is a flawed conception of what is happening. Instead of a singular ‘time’ independent of all monads, Leibniz would say that each clock is rather moving in harmony with the other such that we perceive an illusion of a singular time. Time for Leibniz is a phenomena intrinsic to the monads themselves. Therefore even time cannot be a property independent of monads. The entire universe is filled with an infinite number of monads all acting in concert or harmony. Monads contain their own time and space internal to themselves. Each monad is self-complete; it does not require the external input from another source. This explains the property of monads to be windowless. This is because perceptions do not go through or across monads, but rather come to be known from within the monad itself. This process of uncovering sense perceptions from within is an ‘unfolding.’ The series of successive unfoldings across monadic substance form a harmony where every monad ‘mirrors’ the presence of every other monad. Leibniz tells us this is true even if only to an infinitesimal degree. A monad can only understand the universe from its particular point of view; within that point of view perceptions are formed out of mutual attunement between monads. We can use here the analogy of an orchestra and the production of sound. If an orchestra played in harmony then the sound produced would be a perception whereby each instrument flows in accordance with another. On the other hand if each instrument was to play in random, then this orchestra would be in disaccord. Speaking on the level of composites and aggregates this is Leibniz’ explanation for how we can perceive of the interrelations of monads as rational-based phenomena.
The integrity of these principles gives his explanation plausibility especially given his responses to the main indicts of his conception of the ‘pre-established harmony.’ A crucial correspondence ensues between Leibniz and the Newtonians over the nature of the cosmos. One of the first attacks on the pre-established harmony comes from Samuel Clarke. Clarke advances two objections that are parallel to the trends that take place in the Newton-Leibniz debate for years to come. Clarke first accuses the pre-established harmony of being counter to causality (Vailati, 75). Clarke at this time had invested many years of scholarship in agent causality and saw Leibniz as a rival system that needed to be refuted. In Clarke’s second reply he tries to pin the Leibnizian system as fatalistic and necessitarian. By fatalism Clarke means to say that Leibniz makes all events necessary and determined ahead of their happening. Clarke wants to say that Leibniz discounts the role of free will within the universe.
The first accusation attempts to present causality as a preferable metaphysical explanation to Leibniz’ pre-established harmony. In Clarke’s view there is a cause and effect relationship that can be isolated and observed. Instead of monads that are propelled from within they are actually in interaction with other monads to form cause and effects which we experience as forces and motions. In this picture monads are unintelligible because they lack extension altogether. Clarke believes that Leibniz is unjustified in speaking of the presence of something that has no material grounding.
Leibniz’ response is to say that this explanation via causality violates the Principle of Sufficient Reason because it is impossible within the Leibnizian system to isolate objectively some cause and some effect. For Leibniz the universe is interconnected in the sense that every monad ‘mirrors’ every other monad. This allows Leibniz to say that the Newtonians have no access to a final cause or a final effect. It is impossible for humans to know the cause and effect of any one single event because this would produce an endless chain of events to explain each successive stage in our investigation. At every point in the investigation one is able to ask for the cause of that cause and thus an infinite regression is always possible. The only one able to understand the true causes and effects would be God, because he is the cause of the universe in the first place. The pre-established harmony does not violate the Principle of Sufficient Reason because a monad does not depend on any external cause; a monad unfolds from within. In correspondence with Des Bosses Leibniz utilizes a thought experiment to grasp how he conceives of his system. He says that if God were to annihilate every monad except just one, that this single monad would still maintain the equivalent perceptions had the universe still existed (Phemister, 34). What Leibniz means by this is that the universe does not require causality as the Newtonians conceive of it. Rather than causality the universe just requires an infinite number of monads each self-programmed and whose existence is manipulated by God.
Clarke’s second response accuses the pre-established harmony view of collapsing into fatalism. If all aspects of the world are predetermined according to God’s foreknowledge, then for Clarke this would destroy the capacity for free will. In this sense Clarke believes that free will requires the choice to act. Acting, according to Clarke, depends on a level of indifference to the available options for selection. We should be able to select a choice freely, because anything otherwise would have the characteristic of being acted-upon. This formulation of agent causation is what Clarke calls the “freedom of indifference” (Vailiti, 92). Leibniz responds that the ‘freedom of indifference’ Clarke theorizes would violate the Principle of Sufficient Reason and be contrary to our everyday experience. For Clarke an agent is able to select an available option in a ‘state of equilibrium’ where the preceding mental state does not wholly determine the choice that is to be made. This is in direct contrast with Leibniz who believes that to know any uniform slice of the universe would be to know the entire universe because the universe only progresses rationally. To prove to Clarke that he is ignoring an important element of the equation he introduces the concept of ‘minute perceptions’ which are the unconscious elements that provide reason for our decisions. In this case Leibniz is able to say that there is always a rational succession of events without a state of mental equilibrium; we are unable to consciously know all imperceptible phenomena. Leibniz is rejecting the belief that we can have full “transparency” of the mind (Vailiti, 93). Minute perceptions allows for Leibniz to take into account the confused feeling of ‘indifference’ referred to by Clarke within the decision making process, while simultaneously it allows for him to maintain the Principle of Sufficient Reason.
Leibniz’ also replies that this logic is flawed based on its application to God. If this explanation for free will was applied to God, then this conception of freedom would give God no sufficient reason for the creation of the universe in the first place. It would not make sense to say that God is indifferent about the creation of the cosmos. Leibniz also wants to warn against using absolute or logical necessity as a reason for God’s creation of the universe. If we were to say that God created the universe out of absolute or logical necessity, then this would create a conundrum where God is not free because he was forced to create the universe and all its contents (Rescher, 43). Leibniz’ solution is to remind us that God does not make the cosmos out of absolute or logical necessity but rather creates the universe out of moral necessity. The difference is that the initial creation of the universe is contingent, because God could have not made the universe as such. Leibniz says that the actualization of the cosmos follows from God’s virtue of willing it as so. In this picture God manipulates the existence of monads prior to the creation of the universe such that they operate in accordance with a pre-established harmony.
Clarke was unsatisfied with this perspective and pressed Leibniz further on the intuitive appeal to his agent causation thesis. To this Leibniz explains that the phenomena of causation would not disappear, rather Leibniz reminds us that we do not have access to the full level of perceptions and apperceptions that provide a sufficient reason for their unfolding. With absolute foreknowledge God can program a monad such that it operates with pre-defined operations at each moment in existence. In this sense we still can grasp the feeling and the phenomena of (inter)action even if only retrospectively and without correlation to the actual metaphysical process underlying perceptions. This is not a problem at all for Leibniz who sees no difference in the type of perceptions that a human soul will contain, whether we are fully aware of the reasons for all our actions (only true for Clarke, impossible for Leibniz), versus a pre-established harmony between monads whereby each perception of free will is pre-programmed according to the foreknowledge of God.
Phemister, Pauline. Leibniz and the Natural World: Activity, Passivity, and Corporeal Substances in Leibniz’s Philosophy. Dordrecht, the Netherlands: Springer, 2005. Print.
Rescher, Nicholas. On Leibniz. Pittsburgh, PA: University of Pittsburgh, 2003. Print.
Vailati, Ezio. Leibniz & Clarke: a Study of Their Correspondence. New York: Oxford UP, 1997. Print.