Descartes further investigates the sources of truth and error. While Descartes proved in his previous meditation that God cannot be an evil deceiver and thus the source of our errors, it still remains to be clarified as to how mistakes in our thinking arise:

I find myself exposed to an infinite of deficiencies, so that I must not be surprised if I make mistakes. Thus I discern that error, as such, is not something real which depends on God, but that it is simply a defect; and accordingly, that in order to fall into error I do not need some power given me specially by God […] but that my being mistaken arises from the fact that the power which God has given me to discerning the true from the false is not infinite in me (133).

According to Descartes, the way in which we form true or correct judgments about the world involves the interplay of our intellect and our will.

Regarding the intellect, its role is to consider the perceptual content of our experiences; that is, it is the power by which we can say that something seems to be a certain way to me.

Regarding the will, its role is to give assent or dissent regarding whether or not that which seems to be a certain way is in fact that way (e.