ladder of visible being. In the succeeding chapters he again ascends from bottom to top. Much attention is paid to the argument that the human soul is a separate substance which is united with the body without being affected by the body, as explained by ‘Ammonius, the teacher of Plotinus’ (3, 39.16–40.7). Nemesius regarded the human soul as an immaterial and immortal entity (2, 37.21–38.10). While the highest power of the soul seems to be able to grasp intelligible things directly, it is aware of the sensible reality through activities in which the sense organs are involved (6, 56.2–6, 21–3; 13, 68.18–69.15). 264 Since Nemesius thought that being aware of something is a psychic ability, he apparently assumed that there is also a soul substance in animals, though it is not immor tal. The cognitive capacities of the lower level of the human soul which co-operates with the senses are similar in human beings and in animals, except that the thinking power of humans is greater. 265