 As for the species of motion (Avicenna, [Ph], 2.3), Aristotle and the tradition up to Avicenna had recognized only three specific kinds of motion. These include motion with respect to the categories of quantity, quality and place. Motion with respect to quantity involves augmentation and diminution, while motion with respect to quality includes such changes as alterations in color, temperature and the like. Finally, on the traditional categorization, there is change of place, that is, locomotion, which for a number of reasons was believed to be the most significant or even primary species of motion. Avicenna accepts all three kinds of motion identified by the tradition. He additionally adds to these three, motion with respect to the category of position, that is, the rotation of an object that remains in the same place, like a spinning orb. The reason for his addition is obvious on consideration; for clearly an orb spinning in place is not changing its quantity or quality and by supposition it is remaining in the same place, yet clearly it is moving. Thus what kind of change is it undergoing? Only the relative position of its parts, claims Avicenna, is changing, and thus he concludes rotating objects must be changing with respect to the category of position. 