preestablished harmony

Historical Background and Origins

Preestablished harmony is a technical term in early modern metaphysics, most closely associated with Gottfried Wilhelm Leibniz (1646–1716). It names his solution to several interrelated problems: the mind–body problem, the nature of causation, and the coordination of distinct substances in a universe created by God.

The background lies in 17th‑century debates:

• Cartesian dualism held that mind and body are distinct substances, yet interact causally (e.g., sensations arising from bodily states, voluntary motions from mental decisions). Critics argued that it is obscure how immaterial and material substances can interact.
• Occasionalism (notably in Nicolas Malebranche) denied creaturely causation altogether: God produces all effects on the “occasion” of created events. On this view, what appear as interactions between substances are really sequences of divine interventions.
• Scholastic Aristotelianism had earlier offered interactionist accounts in terms of substantial forms and real qualities, which many rationalists rejected as metaphysically unclear.

Against this background, Leibniz sought to preserve genuine created substances and systematic intelligibility while avoiding both obscure interaction and pervasive divine intervention. His proposal was that God, at creation, pre‑establishes a perfect correspondence among all substances, so that their internal developments unfold in a harmonized way, without any genuine causal influence between them.

The term itself comes through Latin and French formulations used by Leibniz and his interlocutors (e.g., harmonie préétablie), and it rapidly became a label for his distinctive metaphysical system.

Leibniz’s Doctrine of Preestablished Harmony

In Leibniz’s mature metaphysics, the world is composed of monads—simple, immaterial, indivisible substances. Each monad expresses the entire universe from its own point of view and changes according to an internal principle. There is, on this theory, no physical or efficient causation from one created substance to another.

Core idea. Preestablished harmony explains why things seem to interact. Leibniz holds:

1. Every monad has a complete, individual concept containing its entire history.
2. All changes in a monad arise from its own internal nature (its appetitions and perceptions).
3. God, in creating the world, chooses a set of monads whose internal developments are perfectly coordinated.

Thus, when one billiard ball appears to cause the motion of another, or when a decision in my mind appears to cause my arm to move, there is no real causal transaction between distinct substances. Instead, each monad undergoes the changes it was created to undergo, in such a way that the states of different monads correspond lawfully over time.

A standard illustration is the analogy of synchronized clocks: if two clocks are perfectly set at the beginning and continue to function correctly, their hands will move in agreement without any causal influence between them. Similarly, mind and body are like two perfectly synchronized clocks: when the mind wills to raise the arm, the bodily monads enter a state corresponding to arm‑raising, not because the mind pushes the body, but because both follow pre‑established internal laws.

For Leibniz, this harmony has several important features:

• It is universal: it holds not only between mind and body, but among all substances in the universe.
• It is grounded in God’s wisdom: God chooses, among infinitely many possible worlds, the one with the greatest balance of order, variety, and goodness. Preestablished harmony reflects the rational order of this choice.
• It is lawlike: the correlations are not arbitrary but follow general laws (expressible mathematically in the case of bodies, and more obscurely in the case of minds).

In contrast to occasionalism, where God constantly intervenes at each event, Leibniz sees God as a perfect engineer who designs a self‑running system. Once created, the system does not require continual special interventions to maintain coordination; its harmony is built into the initial conditions and natures of substances.

Preestablished harmony also informs Leibniz’s views on freedom and responsibility. Although every monad’s history is included in its complete concept, Leibniz insists that actions are still spontaneous and expressive of the monad’s internal nature. God’s pre‑establishment is compatible, in his view, with a form of compatibilist freedom: human agents act freely when they act in accordance with their rational appetitions, even though their choices fit into a pre‑harmonized order.

Criticisms and Legacy

Preestablished harmony has attracted extensive criticism, both from Leibniz’s contemporaries and from later philosophers.

Contemporary and early modern criticisms.

• Obscurity of non‑interaction: Critics contended that denying all real interaction between substances conflicts with our strong intuition that, for example, bodily injury causes pain or that volitions cause bodily motions.
• Dependence on theology: The doctrine relies on a robust theistic framework—God must create and select the harmonious world. Critics questioned whether such metaphysical dependence could be justified in a philosophical system seeking rational universality.
• Determinism and freedom: Some argued that if all states are fixed in a pre‑established plan, human freedom is illusory, despite Leibniz’s compatibilist claims.

Kant engaged critically with Leibniz, grouping preestablished harmony with occasionalism and interactionism as competing solutions to the mind–body problem. He argued that each assumes we can know the nature of substances “in themselves,” a claim he rejected. For Kant, questions about how mind and body interact (or are harmonized) overstep the proper bounds of empirical and critical inquiry.

Modern and contemporary perspectives.

In present‑day philosophy, preestablished harmony is not typically defended as a literal metaphysical doctrine, but it plays several roles:

1. Historical benchmark: It is a central reference point in the study of early modern rationalism, illustrating one radical strategy for reconciling mechanism, theology, and mental phenomena.
2. Model for “coordination without interaction”: Some contemporary discussions, for example in philosophy of mind and philosophy of science, draw analogies with preestablished harmony when exploring frameworks where:
   • mental and physical domains are correlated but not causally related, or
   • different levels of description (e.g., microphysics and macro‑laws) exhibit systemic coordination grounded in initial conditions or structural features rather than direct cross‑level causation.
3. Philosophy of religion: The doctrine is sometimes revisited in debates about divine providence and the problem of evil, as an example of a front‑loaded model of divine action, where God’s creative choice establishes all subsequent order without ongoing special interventions.

Critics today often view preestablished harmony as metaphysically extravagant, especially its commitment to innumerable non‑interacting simple substances and a strong form of divine design. Proponents of more modest analogies see value in its conceptual lesson: that apparent interaction can, in principle, be explained by correlations grounded in prior structure, rather than by direct exchange of causal influence.

As a technical term, preestablished harmony thus primarily names Leibniz’s specific metaphysical solution, but it also serves more broadly as a label for explanatory strategies that account for systematic coordination among distinct domains or entities without postulating direct causal commerce between them.