Meditation 4 — Of Truth and Error

Descartes is now sure that whatever God created is good and that God is not a deceiver. But he still makes mistakes. God gave him his faculties; if those faculties are good, how can they produce error? The question is real and must be answered if the project of rebuilding knowledge on indubitable foundations is to succeed.

His answer turns on the relationship between two faculties: the intellect, which perceives; and the will, which assents or dissents. The intellect is not unlimited — there are many things it does not clearly perceive. But this is not a defect; it simply reflects the difference between finite and infinite understanding. The will, by contrast, is in a sense unlimited: I can assent to any proposition that comes before my mind, whether or not I understand it clearly. Error arises precisely when the will extends beyond the scope of the intellect — when I affirm or deny something I do not clearly and distinctly understand.

The remedy follows: train the will to withhold assent from anything not clearly and distinctly perceived. This is not a negative result — it is the positive discovery that intellectual error is always a form of excess, never a simple defect of the instruments. The intellect, operating within its proper range, does not err. And the proper range can be expanded by doing philosophy well: by attending more carefully, by suspending judgment, by building knowledge slowly on foundations that cannot be doubted. Meditation 4, the shortest of the six, quietly makes good epistemic practice a matter of moral character.