3. There cannot be an infinite chain of cause and effect, even if these links are not possessed of magnitude, for example, intellects.
4. Change is found in four categories. In substance—genesis and decay. In quantity—growth and diminution. In quality—qualitative change. In place—motion of translation.
5. All motion is change, and is the realization of the potential.
6. Motion may be per se, per accidens, forcible, partial, the latter coming under per accidens. An example of motion per se is the motion of a body from one place to the next; of motion per accidens, when the blackness of an object is said to move from one place to another. Forcible motion is that of the stone when it is forced upward. Partial motion is that of a nail of a ship when the ship moves.
7. Every changeable thing is divisible; hence every movable thing is divisible, i. e., every body is divisible. What is not divisible is not movable, and hence cannot be body.
8. That which is moved per accidens is necessarily at rest because its motion is not in itself. Hence it cannot have that accidental motion forever.
9. A body moving another must itself be in motion at the same time.
10. Being in a body means one of two things: being in it as an accident, or as constituting the essence of the body, like a natural form. Both are corporeal powers.
11. Some things which are in a body are divided with the division of the body. They are then divided per accidens, like colors and other powers extending throughout the body. Some of the things which constitute the body are not divisible at all, like soul and intellect.
12. Every power which extends throughout a body is finite, because all body is finite.