The Nature of Motion

In everything that which moves should be divided from that which is moved as we see in things inanimate when anything animated moves them. These are always moved by something and this will become evident to those who divide causes what is asserted also may be assumed in mode of natures. Some things are motive contrary to their own nature but others are naturally motive thus that which isHot in energy is motive of that which is hot in capacity the like also takes place in other things of a similar kind. Things light and heavy for these are moved by violence to opposite places but to their proper places naturally the light indeed upward in the heavy downward.