On The Soul   

why, if deprived of food, it must cease to be.

The process of nutrition involves three factors, (a) what is fed,

(b) that wherewith it is fed, (c) what does the feeding; of these

(c) is the first soul, (a) the body which has that soul in it, (b) the

food. But since it is right to call things after the ends they

realize, and the end of this soul is to generate another being like

that in which it is, the first soul ought to be named the reproductive

soul. The expression (b) 'wherewith it is fed' is ambiguous just as is

the expression 'wherewith the ship is steered'; that may mean either

(i) the hand or (ii) the rudder, i.e. either (i) what is moved and

sets in movement, or (ii) what is merely moved. We can apply this

analogy here if we recall that all food must be capable of being

digested, and that what produces digestion is warmth; that is why

everything that has soul in it possesses warmth.

We have now given an outline account of the nature of food;

further details must be given in the appropriate place.



5



Having made these distinctions let us now speak of sensation in

the widest sense. Sensation depends, as we have said, on a process

of movement or affection from without, for it is held to be some

sort of change of quality. Now some thinkers assert that like is

affected only by like; in what sense this is possible and in what

sense impossible, we have explained in our general discussion of

acting and being acted upon.

Here arises a problem: why do we not perceive the senses

themselves as well as the external objects of sense, or why without

the stimulation of external objects do they not produce sensation,

seeing that they contain in themselves fire, earth, and all the

other elements, which are the direct or indirect objects is so of

sense? It is clear that what is sensitive is only potentially, not