2. Of things that move, some have the cause of their motion within themselves; others, again, are moved only from without. Now only portable things are moved from without, such as pieces of wood, and stones, and all matter that is held together by their constitution alone. And let that view be removed from consideration which calls the flux of bodies motion, since it is not needed for our present purpose. But animals and plants have the cause of their motion within themselves, and in general whatever is held together by nature and a soul, to which class of things they say that metals also belong. And besides these, fire too is self-moved, and perhaps also fountains of water. Now, of those things which have the cause of their movement within themselves, some, they say, are moved out of themselves, others from themselves: things without life, out of themselves; animate things, from themselves. For animate things are moved from themselves, a phantasy springing up in them which incites to effort. And again, in certain animals phantasies are formed which call forth an effort, the nature of the phantasy stirring up the effort in an orderly manner, as in the spider is formed the phantasy of weaving; and the attempt to weave follows, the nature of its phantasy inciting the insect in an orderly manner to this alone. And besides its phantasial nature, nothing else is believed to belong to the insect. And in the bee there is formed the phantasy to produce wax.