Monads and idealism: are the ultimate constituents of reality simple immaterial substances, with bodies less than fully real?

Gottfried Wilhelm Leibniz, answered from the texts and cited to the page.

The position in brief

Whatever is real must be a genuine unity, for what has no true unity has no true being; an aggregate borrows its reality from the unities that compose it. Extended matter, being infinitely divisible, is never one, and so cannot be the foundation of things. The foundation is the monad — a simple substance, without parts and therefore immaterial, whose nature is to perceive and to strive.

Bodies are not unreal but are well-founded phenomena, aggregates grounded in monads, real as the rainbow is real and not as a substance is.12 The mature view is thus a form of idealism: the perceiving unities are first, and the material world is their well-founded appearance. The earlier philosophy granted corporeal substance more standing, and the bond explored with des Bosses was a genuine late experiment.34

Sources

  1. But even if the bread or the wine is not a substantiated being constituting a unity per se and hence is not unified by a substantial chain, it is still an aggregate of organic bodies or substances constituting a unity per se, whose substantial chains would be destroyed and replaced by the substantial chain of the body of Christ.......
    Correspondence with Des Bosses, 1709-15, p. 619
  2. Itaque non puto me a doctrina scholarum circa substantias corporeas abire nisi in hoc uno quod verae substantiae sive simplicis sive compositae generationem et corruptionem tollo, quia nec necessarias, nec explicabiles esse reperio; atque ita philosophiam istam innumeris difficultatibus libero. Sed ita substantiam Leibniz to Des Bosses whereas monads can exist even if bodies should be only phenomena.
    The Leibniz-Des Bosses Correspondence, pp. 455–456
  3. Dicis modificari substantialiter esse monades habere modum, qui eas faciat naturale principium operationum. Sed quid quaeso ille Modus, est ne qualitas, est ne actio? Mutatne Monadum perceptiones? Nihil tale dici debet; revera substantia est, non monadum modus; etsi naturaliter ei Mo- nades respondeant. Monades non sunt principium operationum ad extra.
    The Leibniz-Des Bosses Correspondence, pp. 451–452
  4. No creature, however excellent, can at once distinctly perceive or comprehend the infinite; on the contrary, indeed, whoever were to understand a single part of matter would understand the whole universe, by virtue of this same nepixapijotv of which I spoke. My principles are such that they can hardly be tom apart from each other. He who knows one well, knows them all IV.
    Correspondence with Des Bosses, 1709-15, p. 612

Where the argument is made

  • Discourse on Metaphysics (1686)
  • Monadology (1714)
  • Principles of Nature and Grace (1714)
  • the correspondence with Bartholomew des Bosses (on the vinculum substantiale, ed. Look and Rutherford, Yale 2007)
  • 'A New System of Nature' (1695)

How the argument was received

The central battleground of modern Leibniz scholarship. Adams reads the mature metaphysics as a pure idealism of monads and their perceptions; Garber traces a development in which the middle-period Leibniz was a realist about corporeal substance grounded in force; Catherine Wilson holds the system never fully settled. The status of body and the vinculum substantiale remain genuinely contested, and Jolley grants the question was left unresolved at the end.