nerves

The organs of touch are at the ends of the nerves, which also have the power of moving the living creature; it is there that the soul offers itself in that capacity. The nerves start in the brain (enkephalos) and it is there that people locate the principles of perception, impulse and of the whole living creature, obviously assuming that where the principles of the organs are, there is to be found what is going to use them. It would be better to say that the principle of the actualisation of the potentiality is located there; for where the source of movement in the organ resides, there must be fixed the potentiality of the workman, as it were, which is appropriate to the organ, or rather not so much the potentiality (for the potentiality is everywhere in the body) – but the principle of the actuality is where the principle of the organ is. (Ennead IV, 3, 23)