Basically...

Basically, motion in position may be reduced to spatial motion because although in motion in position the place of the entire body does not change, the parts of the moving thing gradually change location, so that, for example, the part which was to the right moves to the left, or the part which was above moves below. The discussion of whether position is really a category is similar to that about the category of where ( ’ayn ).

The division of motion in position into intentional and the non-intentional is similar to the corresponding division in spatial motion. A notable point is that philosophers do not consider circular motion to be required by nature, and in this regard modern physics says that motion which is not in a straight line must be the resultant of several forces. The final judgment about this kind of problem is the responsibility of the empirical sciences.

Motion in Quality The third category in which motion occurs is the category of quality. It may be further subdivided by attending to its kinds, such as motion in mental quality, motion in sensible quality, motion in qualities specific to quantity and motion in dispositional qualities ( kayf isti‘dādī ). The most indubitable among the types of motion in quality, is motion in mental quality, for it is perceived by infallible presentational knowledge.

For example, everyone finds within themselves an affection or love for someone or something, and gradually this attraction becomes intense. Or one feels a dislike toward someone or something which gradually changes into an intense loathing, or the opposite, a state of intense anger appears and gradually is mollified, or a state of intense joy appears and gradually vanishes. From a philosophical point of view, these gradual changes are considered motion.

Motions such as these may be considered to be like sensible qualities, such as color, but we know that the reality of color and the qualities of their intensity and weakness are still subjects of discussion among physicists. Therefore, the existence of this type of motion in quality is not as certain as the previous type. The third type of motion in quality is motion in shape.

If two ends of a string which are extended to form a straight are line gradually brought together in such a way that a curve is formed, then the plane surface and its straight line (if the line it possesses is actual) gradually becomes curved.