Lovejoy, Arthur - Plentitude and Sufficient Reason in Leibniz and Spinoza

11/01/2013

The Great Chain Of Being, Ch 5 Harvard University Press, 1936

Author sets out to discuss the relationship between Leibniz's principle of plenitude and his principle of sufficient reason, and whether Leibniz can avoid "absolute logical determinism" that characterizes Spinoza. Author starts by reminding us of Leibniz's writings on the 'single chain' of 'natural beings', that is a gradation and not strict species and genus divisions (pg145). The discussion moves to the principle of sufficient reason, and an inspection of the various (imprecise) formulations of it that Leibniz uses. Author argues that Leibniz's primary motivation is not to justify the particulars of the universe as "goods" but merely as non-arbitrary (pg146-8). Most thinkers of the time held a division between concepts (roughly, Platonic ideas) and objects, with concepts being maintained (for Leibniz) in the mind of God: it was here where ultimate reasons for existence "were to be sought" (pg147-8). The strategy here was to combine the two realms into one, and to add to the realm of objects the reason for their existence, in which case their existence would be self-justifying (pg148-9).

Author explores the thinking of the time relating to the origin of the universe and the "first cause", which must have been internal to itself and independent of other causes, in a word, God (pg149-151). The next question, answered in the affirmative by Spinoza, is whether only God's existence is justified, or whether such justification extends to all objects (pg151-3). The problem for Spinoza, as presented by author, is that the principle of plenitude should have resulted in all beings existing all at once, and not the creation and cessation of things over time (pg154-5). The alternative to Spinoza, according to author, is not to deny the necessary existence of God, but to deny the necessary existence of creation (pg156-165) (cf Duns Scotus, Aristotle, Augustine). In this conception, God creates the universe without motive. Author discusses Milton's struggles with these two ideas for some time (pg160-2).

Author turns back to Leibniz to explore his principle of sufficient reason (pg166-8). Leibniz agrees with Spinoza, against the previously discussed philosophers, that God must have some reason for creating things. Author imputes two reasons for Leibniz's beliefs: (1) as a principle of psychology all conscious choices must have motivating reasons and (2) practically, it is intolerable to believe that chance is the principle of the universe. Author reviews the challenge of Buridan's ass leveled by Clarke against Leibniz (pg168-9), and Leibniz's clumsily response. Author then introduces Leibniz's third alternative, between the determinism of Spinoza and the chance of his critics: that the world so created must not only be logically possible but also "compossible", consistent with each other. Thus the formation of "sets" of entities, and thus many different possible worlds, from which God chooses one, using God's will (a concept Spinoza seems to leave out from God) (pg170-1). The second feature that he needed, above the concept of compossibility, is that of "moral necessity" instead of metaphysical necessity (pg172-3). Author concludes this second distinction has no "logical substance" and that Leibniz is thus mostly equivalent to Spinoza (pg174-6).

Author goes on to argue that Leibniz's principle of sufficient reason "pass[es] over explicitly into the principle of plenitude"(pg177), which author discusses next (pg177-180). The problem for Leibniz is that sometimes he speaks of a degree of perfection in monads (in things), and thus might be caught into having to argue that a world with more eg, human monads, is better than one with eg, crocodile ones. But Leibniz needs to justify crocodiles, so he asserts that all monads have equal rights to existence (pg179). Instead, Leibniz places value on diversity of essence, not just quantity of more perfect ones. Author finally discusses Leibniz's response to those who believed in the possibility of a physical vacuum. Here Leibniz seems to eschew the principle of plenitude in favor of panpsychism and anti-materialism, which argues that minds, not matter, are the fundamentals of the universe (pg181-2).