18. This way of talking causes confusion of thought.
This way of talking, nevertheless, has prevailed, and, as I
guess, produced great confusion. For these being all different powers in the mind, or in the man, to do several
actions, he exerts them as he thinks fit: but the power to do one action is not operated on by the power of doing
another action. For the power of thinking operates not on the power of choosing, nor the power of choosing on the
power of thinking; no more than the power of dancing operates on the power of singing, or the power of singing
on the power of dancing, as any one who reflects on it will easily perceive. And yet this is it which we say when
we thus speak, that the will operates on the understanding, or the understanding on the will.
