لأنا نفرق بالضرورة بين حركة البطش وحركة الارتعاش
We immediately recognize a difference between a hand moved to strike and a hand moving because of a tremor.
The first is ordinarily directed toward a chosen end, whereas the second may occur without the person's control. Both involve physical movement, but the relation to intention and choice is different.
The difference cannot always be read from outward appearance alone. Two movements may look similar while arising from very different states of control and intention. Moral responsibility therefore cannot be inferred merely from the presence of bodily motion.