One of the most notorious philosophical hills to climb is the reconciliation of the material world and the mind, and Leibniz climbs this hill through his argument for predetermined harmony. In Leibniz’ work the monadology, Leibniz establishes that monads “(infinitesimal Psychophysical entities)”(10) are like Leibniz’ version of philosophical atoms. Monads, unlike atoms, are beyond the physicality of atoms, and can be best described as a unit of existence. Because monads act as philosophical building blocks for all things (physical and non-physical) monads cannot bebroken down, altered, or causally interact at all. From this Leibniz then concludes that because monads cannot causally interact, substances created from monads cannot causally interact either. Mind and material while very philosophically different, are both substances created from monads, the philosophical atoms of reality. Thus, “human minds and their bodies—as well as any created substances, in fact—cannot causally interact”(3). The problem with no causal interaction between the physical and mental reams, however, is that if this statement is true, then when I try to use my mind to move my fingers or arms, nothing would happen. Seemingly, this would defeat Leibniz’ philosophy; every time I try to use my mind to move my fingers or my arms, it works. But, because of Leibniz’ pre-established harmony; Leibniz’ philosophy is not beaten, and instead his philosophy remains just as argumentatively stable as it was before.

Imagine a swing set with two swings, and on that swing set, both swings are swinging back and forth perfectly synchronized. These swings are constantly in a state of synchronization and are always aligned perfectly next to each other. A materialist, believing that “everything is made of matter and energy”(8) would explain that the swings are swinging together because one swing (the superior swing) controls the actions of the other swing. An occasionalism would explain that these two swings are constantly adjusted and maintained every step of the way by a god who manually ensures both swings swing together. Leibniz would disagree with both and instead argue that a god prior to the time of swinging pushed these two swings perfectly and identically at the same time, so that even though these two swings never interact or affect each other, they move in tandem and appear to be mirroring each other. Simply imagine that instead of one swing, we have the mental realm, and instead of the other swing, we have the physical realm. This leaves us with Leibniz’ pre-determined harmony, the idea that “what appear to be real causal relations between mind and body are, in metaphysical reality, the mutual conformity or coordination of mind and body”(4). Instead of mind and body interacting and affecting each other, they are simply swinging in synchronization from a common cause that pushed them to do so: god and his monads.

reference[edit | edit source]

  1. Adams, Robert M. "Possible Worlds." Cambridge Dictionary of Philosophy, edited by Robert Audi, 2nd ed., Cambridge University Press, 1999, pp. 724-725. Gale Ebooks, Accessed 30 Sept. 2019.
  2. Antognazza, Maria Rosa. Leibniz a Very Short Introduction. Oxford University Press, 2016.
  3. Jordi, Juila. “Gottfried Leibniz: Philosophy of Mind.” Internet Encyclopedia of Philosophy,
  4. Kulstad, Mark, and Laurence Carlin. “Leibniz's Philosophy of Mind.” Stanford Encyclopedia of Philosophy, Stanford University, 11 Nov. 2013,
  5. Leibniz, Gottfried Wilhelm. The Monadology. Translated by Robert Latta, Clarendon Press, 1898.
  6. Leibniz, Wilhelm Gottfried. Theodicy. Edited by Austin Farrer. Translated by E.W Huggard, 1951, Theodicy Essays on the Goodness of God the Freedom of Man and the Origin of Evil,
  7. Leibniz, Wilhelm Gottfried. “Varying Sections between Section 8-161.” Theodicy , 1709, pp. 8–161.
  8. Philosophy. “Materialism.” Philosophy Terms, 25 Oct. 2018,
  9. Sleigh, Robert C. "Leibniz, Gottfried Wilhelm." Cambridge Dictionary of Philosophy, edited by Robert Audi, 2nd ed., Cambridge University Press, 1999, pp. 491-494. Gale Ebooks.
  10. The Editors of Encyclopaedia Britannica. “Preestablished Harmony.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 19 June 2017,
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