[Revised entry by Marc Bobro and Tobias Flattery on September 30, 2026.
Changes to: Main text, Bibliography]
According to Gottfried Wilhelm Leibniz (1646 – 1716), the basic, fundamental entities of the universe (simple substances or “monads”) are causally active in a distinctive manner, each possessing forces that are causally efficacious in bringing about all of their perceptual states respectively, while having no causal influence over the states of other, numerically distinct substances. They continually change their perceptions, and thus are constantly active. “It is in the nature of created substance to change…

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