The causal adequacy principle (CAP), or causal reality principle, is a philosophical claim made by René Descartes that the cause of an object must contain at least as much reality as the object itself, whether formally or eminently.
Descartes defends CAP by quoting Roman philosopher Lucretius: "Ex nihilo nihil fit", meaning "Nothing comes from nothing".—Lucretius[1]: 146–482 In his meditations, Descartes uses the CAP to support his trademark argument for the existence of God.
[2]: 430 Descartes' assertions were disputed by Thomas Hobbes in his "Third Set of Objections" published in 1641.
[4]: 54–56 It is used in the classical metaphysics of Plato and Aristotle, and features eminently in the works of Thomas Aquinas.
Similarly, a person can eminently possess money by owning assets that could readily be exchanged for it.