Gottfried Wilhelm Leibniz

Background

Gottfried Wilhelm Leibniz (1646–1716) — polymath, co-inventor of the calculus, and career counsellor-librarian to the House of Hanover — is the rationalist philosopher whose name attaches to the contingency form of the cosmological argument. His system rests on "two great principles": contradiction, and "that of sufficient reason, in virtue of which we hold that there can be no fact real or existing, no statement true, unless there be a sufficient reason, why it should be so and not otherwise" (Leibniz, Monadology §§31–32). He is also the source of the best-possible-world theodicy (Théodicée, 1710) and of the possibility-completion repair to Descartes' ontological argument.

A corpus note: the The Leibnizian (Contingency) Cosmological Argument article was compiled from SEP reconstructions before Leibniz's own text was ingested. The Monadology is now in corpus, and the load-bearing sections are verifiable directly: since the analysis of contingent things "might go on into endless detail," the "sufficient or final reason must be outside of the sequence or series of particular contingent things, however infinite this series may be. Thus the final reason of things must be in a necessary substance… and this substance we call God" (Monadology §§36–38).

Positions held in this wiki

• The Leibnizian (Contingency) Cosmological Argument — the canonical formulation: from the PSR to a necessary being outside the series of contingents; the argument needs no beginning of the universe, only its contingency.
• The Ontological Argument — the possibility-completion strategy: "God alone (or the necessary Being) has this prerogative that He must necessarily exist, if He is possible" (Monadology §45); Leibniz held Descartes' proof incomplete until the coherence of a supremely perfect being is shown (SEP §1).
• The Logical Problem of Evil — noted there as the early-modern descendant of Augustinian theodicy (Théodicée, not in corpus).

Key works in our corpus

• Monadology (1714, Wikisource edition) — in corpus. Key sections: §§31–32 (the two principles), §§36–38 (the contingency argument), §45 (the a priori and a posteriori proofs combined), §53 (sufficient reason for God's choice among possible worlds).

Corpus gap: the Théodicée (1710) and New Essays remain uningested; the theodicy is represented only at second hand.

Principal critics

• David Hume — the Part-9 Dialogues battery: no a priori demonstration of existence; "necessary existence" without meaning; parity of necessary matter.
• Immanuel Kant — the charge that the contingency argument covertly relies on the ontological argument.
• Baruch Spinoza — less critic than rival: the same PSR driven to an immanent, necessitarian conclusion.
• Peter van Inwagen — the modern modal-collapse argument against the PSR itself.

See also

• Thomas Aquinas — the Third Way, the argument's medieval ancestor.
• William Lane Craig and Richard Swinburne — contemporary endorsement and probabilistic reformulation, respectively.
• René Descartes — the rationalist predecessor whose ontological proof Leibniz sought to complete.