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.
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.[3]: 379
René Descartes was not the founder of this philosophical claim.[4]: 54–56 It is used in the classical metaphysics of
Plato and
Aristotle, and features eminently in the works of
Thomas Aquinas.
Details
A "cause" is that which brings something into effect.
If an item has the quality X formally, it has it in the literal or strict sense.
If an item has the quality X eminently, it has it in a higher or grander form.
To demonstrate this, a person can possess money formally by holding it on their person, or by storing it in a bank account. Similarly, a person can eminently possess money by owning assets that could readily be exchanged for it.[5]: 155–156
Descartes offers two explanations of his own:[6]: 28
Heat cannot be produced in an object which was not previously hot, except by something of at least the same order of perfection as heat.
A stone, for example, which previously did not exist, cannot begin to exist unless it is produced by something which contains, either formally or eminently everything to be found in the stone.
Descartes goes on to claim that the CAP not only applies to stones, but also the realm of ideas, and the features that are seen as part of the objective reality of an idea.[7]: 33–35
References
^Carus, T. L., De Rerum Natura (Oxford: Oxford University Press, 1947), pp. 146–482.
^Campbell, M., Time and Narrative in Descartes’s Meditations, dissertation under the tutelage of profs. P. Magee and A. Dickerson,
University of Canberra, January 2018,
pp. 54–56Archived 2019-12-21 at the
Wayback Machine.