Must we attribute sensation to each power, but in a different manner?
In this case, for instance, it will be sight, and not appetite, which
will perceive sense-objects; but appetite will be later wakened by
sensation which will be "relayed," (as the Stoics would say); and
though it does not judge of sensation, it will unconsciously feel the
characteristic affection. The same state of affairs will obtain with
anger. It will be sight which will show us an injustice, but it will
be anger which will resent it. Just so, when a shepherd notices a wolf
near his flock, the dog, though he have not yet observed anything, will
be excited by the smell or noise of the wolf. It certainly is appetite
which experiences pleasure, and which keeps a trace of it; but this
trace constitutes an affection or disposition, and not a memory. It
is another power which observes the enjoyment of pleasure, and which
remembers what occurred. This is proved by the fact that memory is
often ignorant of the things in which appetite has participated, though
appetite still preserve traces thereof.