An important component for Descartes’ account of free will is explaining where it is that human error comes from. After the first three meditations, Descartes has arrived at the conclusion that “it is impossible that God should ever deceive [him]” (Fourth Meditation, 37). When discussing the faculty of judgment, Descartes notes that, “like everything else which is in [him], [he] certainly received from God [this faculty]” (Ibid). If you accept that the faculty of judgment comes from God, and that God is a perfect non-deceiver, then it seems that you would arrive at the conclusion that it would be impossible for the faculty of judgment to ever go wrong. After all, how could a faculty received from God be anything less than perfect? It is at this point that Descartes becomes concerned with explaining the origins of human error, because though the faculty of judgment comes from God, human beings frequently make mistakes.
At this point Descartes notes that though he was made by God, he is not God-like, but rather “something intermediate between God and nothingness, or between supreme being and non-being” (Fourth Meditation, 38). As intermediates between God and nothingness, human error does not have to come from God: it is merely a defect that comes from being an imperfect being. Descartes looks closely at himself to determine the nature of human error and notices that it depends on two concurrent causes: the faculty of knowledge, which is within him, and the faculty of choice or freedom of the will (Fourth Meditation, 39). In other words, human error depends simultaneously on the intellect and the will. Descartes immediately rules out the intellect as the source of human error because all the intellect does is enable him to perceive ideas which are subjects to possible judgment. Human error surely cannot arise from the power to perceive.
Accordingly, it would seem that the source of human error must be the will, but Descartes does think that this is so. Since the will or freedom of choice was given to him by God, Descartes believes it to be sufficiently extensive and perfect. Further, Descartes argues that his will is infinite since it is not restricted in any way. The will is a judging faculty that “simply consists in our ability to do or not do something (that is, to affirm or deny, to pursue or avoid)” and thus anything presented before the will can be judged either positively or negatively without limit (Fourth Meditation, 40).
So then what is the source of human error? Descartes believes that human error arises because the scope of the will is wider than that of the intellect: the will is infinite, but the intellect is finite. The intellect can only understand so much, but the will, being infinite, can judge anything, including matters it fails to understand. For every volition, there is a perception from the intellect. These perceptions are passed on to the intellect to be judged. The problem arises because the intellect, being finite, cannot distinctly perceive everything. As such, some perceptions are confused. The will may then affirm these confused perceptions not realizing that their perceptions are confused. This is the cause of human error. Had the intellect been able to distinctly perceive the volition, the will would have chosen not to affirm it, but since the intellect was confused in its perception, the will affirmed something it otherwise would not. When these confused perceptions are passed along to the will, the will may affirm needs to be some perception. In other words, human error surfaces when people attempt to judge things that are beyond the scope of human understanding.
Descartes then proceeds to offer a solution to those who are seeking to avoid error. When the intellect presents the will with a perception, the agent should refraim from forming any sort of judgement unless the perception is clear and distinct. If the perception is doubtable or hazy in any way, there is the risk of error, and judgment should be avoided. If the agent was to affirm a hazy perception, and coincidently affirmed correctly, then the agent has successfully avoided error. However, affirming hazy perceptions is dangerous, and if he was to affirm incorrectly, then he has committed an error and has moved further away from the truth. The risk of affirming a confused perception incorrectly is too great, and it is better to remain cautious for fear of choosing counter to the truth. People cannot err if they do not choose. Thus, the more sure a person is of his direction “either because [he] understand[s] the reasons of truth and goodness point that way, or because of a divinely produced disposition of [his] inmost thoughts – the freer is [his] choice” because the more sure he is of choosing truth and goodness, the more likely he is to avoid error (Fourth Meditation, 40).
Descartes concludes by noting that God is not to be blamed for human error, for it is not the fault of God that human beings seek to judge things that are beyond the reach of their understanding. It is the duty of human beings to get into the habit of avoiding error by being cautious with their judgments by only judging cases that are certain. If human beings are able to restrain their wills to cases where the intellect clearly and distinctly perceives (ie: logical truths, math, the proof of God’s existence, the Cogito, etc.), then it is impossible that human beings should ever err.