Spinoza and Leibniz
Substance, monad, and the meeting in the Hague
Venue: Visit at The Hague, November 1676; earlier indirect correspondence (Tschirnhaus, Oldenburg); Leibniz's posthumous *Refutation of Spinoza* (1854) and lifelong written engagement.
The greatest rationalist substance-monism and the greatest rationalist substance-pluralism, briefly in the same room.
In November 1676 Leibniz visited Spinoza at The Hague and spent several days in conversation, weeks before Spinoza's death. The visit was nominally about physics (Cartesian mechanics); the deeper background was metaphysical. Spinoza's *Ethics* (then unpublished) defended an absolute substance-monism: there is only one substance, Deus sive Natura, with extension and thought as two of its infinite attributes, and finite "things" as modes of that one substance. Leibniz's mature metaphysics moved in the opposite direction: infinitely many substances (monads), each a windowless centre of perception, harmonised by God's pre-established choice. The two rationalisms were systematically opposed: monism vs pluralism, necessity (Spinoza) vs contingent best-world choice (Leibniz), and theological-ethical implications running through both. Leibniz kept Spinoza's influence quiet (Spinoza was a notorious heretic); but his engagement was lifelong and unmistakable.
Historical Context
Spinoza had been excommunicated from the Amsterdam Jewish community in 1656; his *Tractatus Theologico-Politicus* (1670) had been widely condemned. Leibniz was politically and theologically careful throughout his career; public association with Spinozism would have been costly. The 1676 visit was partly an intellectual pilgrimage, partly tactically discreet.
Parties
There is exactly one substance — God or Nature — with infinitely many attributes (we know two: extension and thought). All finite "things" are modes of that one substance. Everything follows necessarily from God's nature.
Key arguments
- Definition of substance: that which is in itself and conceived through itself. Only Deus sive Natura satisfies this.
- Mind and body are the same modification of substance under different attributes; parallelism, not interaction.
- Necessitarianism: God's actions follow from God's nature; the actual world is the only possible world.
- Liberation (the *Ethics* is an ethical project) consists in understanding our place as modes of the one substance; "intellectual love of God" replaces religious and political fear.
Allied schools
There are infinitely many substances — monads — each a windowless centre of perception. They do not interact but are harmonised by God's pre-established choice; the actual world is the best of all possible worlds, chosen by a free God who could have chosen otherwise.
Key arguments
- Monadic pluralism: distinct individuals are required for the diversity, perspective, and harmony we observe.
- Pre-established harmony: monads do not interact but are coordinated by God's choice; this preserves individual integrity and divine sovereignty.
- Best of all possible worlds: God's choice is contingent (logically), constrained only by the principle of sufficient reason (selecting the maximum compossible perfection).
- Theological imperative: a free, choosing God is required for the moral structure of the world; Spinoza's necessitarianism collapses the difference between God and Nature, with grave ethical consequences.
Dimensions Engaged
Matter
Matter · Ontological Status: one substance vs infinitely many; mode vs monad.
Observer
Observer · Number: extended infinite One vs windowless plural perspectives.
Time
Time · Freedom: strict necessitarianism (Spinoza) vs contingent best-world choice (Leibniz).
Verdict in retrospect
Neither system was preserved intact in the canonical philosophical reception, but each has had recurrent influence. Spinoza re-emerged as a major figure in the 1780s Pantheismusstreit, in 19th-century Romanticism, in Deleuze's 1968 *Expressionism in Philosophy*. Leibniz's logic and his work on possible worlds shape modern modal metaphysics (Lewis, Kripke). The 1676 meeting remains one of the great unrecorded conversations of philosophy.
Related Debates
Sharing parties or aligned schools.
Related Experiments
Experiments that share dimensions and/or aligned schools with this debate.
Other Personas Aligned With This Debate
Ranked by declared-influence weight in the schools either party is allied with. The named parties themselves are excluded — they're already listed above.
Works Most Aligned With This Debate
Ranked by declared-influence weight in the schools either party is allied with.
Related Films
Films engaging the same dimensions as this debate.
Related Contemporary Dilemmas
Dilemmas that engage the same dimensions as this debate.
Further reading
- Spinoza, *Ethics* (1677)
- Leibniz, *Monadology* (1714); *Theodicy* (1710)
- Stewart, *The Courtier and the Heretic: Leibniz, Spinoza, and the Fate of God in the Modern World* (2006)