Whence then come my errors? They come from the fact that my will is much wider in range than my understanding, and extending it to things which I do not understand I fall into error and sin. If I abstain from giving judgement on things that I do not perceive with clearness and distinctness, it is plain that I act rightly. But if I determine to affirm what is not true, then I deceive myself, and misuse free will to create error.
There is a great difference between mind and body, as body is by nature always divisible, and the mind is indivisible. When considering the mind, I cannot distinguish in it any different parts. And although the whole mind seems united to the whole body, yet if a foot or an arm is separated from my body, nothing has been taken away from my mind. Those faculties of willing, feeling, conceiving, etc. cannot be said to be its parts, for it is one and the same mind which employs itself in willing and in feeling and understanding. But I know that corporeal objects can readily be divided into parts, which alone would teach me that the mind or soul is entirely different from the body, if I had not already learned it from other sources.