Doubt and certainty › Clear and Distinct Perception

With God's existence established (at least to Descartes' satisfaction), the Fourth Meditation addresses the question of error. If God is perfect and non-deceiving, why do we make mistakes? Descartes' answer is that error arises from the misuse of our faculties, not from any defect in the faculties themselves. God has given us understanding (the faculty of perceiving ideas) and will (the faculty of judgment). The understanding is limited—we do not perceive everything clearly. But the will extends beyond what the understanding clearly presents: we can affirm, deny, or suspend judgment about matters we do not fully understand. This is a comparison between the scope of judgment and the limits of understanding, not a claim that human beings can do anything they choose. Error occurs when we extend our will beyond our understanding, when we judge about matters we do not clearly perceive. If we restrict our judgments to what we clearly and distinctly perceive, we will never err. > **Clear and Distinct Perception** > > Descartes' criterion for truth. An idea is clear when it is present and manifest to an attentive mind. It is distinct when it is so precise that it contains nothing but what is clear. What we clearly and distinctly perceive is true, because a perfect God would not allow us to be systematically deceived about such perceptions. This creates what scholars call the "Cartesian Circle." Descartes seems to argue: (1) I can trust clear and distinct perceptions because God exists and is not a deceiver; (2) I know God exists because I clearly and distinctly perceive the arguments for his existence. But if clear and distinct perception requires God's guarantee, how can Descartes use it to prove God's existence? Descartes' defenders argue that the circle is only apparent. The cogito, for instance, does not require God's guarantee—it is self-evident in the moment of thinking. On this interpretation, the divine guarantee secures remembered clear and distinct judgments when we are no longer attending directly to their reasons. This response and the objection it answers are examined in the [Stanford Encyclopedia discussion of Descartes' epistemology](https://plato.stanford.edu/entries/descartes-epistemology/). The circle remains an interpretive dispute, rather than a difficulty that the chapter can settle by repeating Descartes' answer.