Key Ideas
1. Compounds require simple unities
Leibniz argues that an aggregate cannot be fundamental. Genuine multiplicity presupposes units that are not themselves further aggregates.
2. Monads are non-spatial
A monad has no extension, shape or divisible parts. It is a metaphysical substance rather than a tiny material object.
3. Every monad is qualitatively unique
If two monads had no intrinsic difference, there would be no sufficient basis for treating them as distinct beings.
4. Change comes from within
A monad’s states develop according to its internal principle; no external object enters its inner constitution.
5. Perception is wider than consciousness
Representation can occur without reflective awareness, allowing Leibniz to describe unnoticed and confused mental states.
6. Appetition drives transition
The tendency from one perception towards another supplies the active principle of a monad’s unfolding life.
7. Mental life has degrees
Bare perception, animal memory and rational reflection represent increasing clarity rather than wholly unrelated kinds of being.
8. Reason uses contradiction
Necessary truths are established by analysing concepts until denial is shown to involve inconsistency.
9. Facts require sufficient reasons
A contingent event cannot be explained merely by saying that it happened; reason asks why it occurred in this way.
10. God grounds contingent reality
The sequence of finite explanations leads Leibniz to a necessary being whose reason for existence lies within itself.
11. Possible worlds differ in perfection
Divine wisdom compares complete orders of possibility, selecting the arrangement that combines maximal variety with order.
12. Each monad mirrors the universe
Every simple substance expresses the same whole from a distinctive and limited point of view.
13. Harmony replaces direct interaction
The correspondence between substances is established in their laws rather than produced by physical influence between monads.
14. Rational spirits form a moral community
Self-conscious beings can know reasons and enter relations of justice, adding a kingdom of grace to natural order.