Notes on the causal principle in Descartes’ Third Meditation

In Descartes’ Third Meditation he states that it is manifested by the natural light “that there must be at least as much ‘reality’ in the efficient and total cause as in the effect of that cause” (AT, VII, p. 40). What this formulation of the causal principle seems to affirm is that the effect can never be more real than its cause. Nevertheless, during the Third Meditation, Descartes seems to specify the formulation of the causal principle when he states that the effect must be contained in the cause, formally or eminently. What kind of specifications are these? Are they explanations of the causal principle or are they new contents added to the principle? The aim of this paper is to discuss which and how many are the formulations of the causal principle in Descartes’ Third Meditation. Keywords: Descartes, causal principle, containment principle, preexistence principle, communication principle.