house built? that furniture may be preserved; the one is for the sake of health, but the other for the sake of preservation. Still there is no difference between why is it necessary to walk after supper, and for the sake of what is it necessary? but let walking after supper be C, the food not to rise B, to be well A. Let then walking after supper be the cause why the food does not rise to the mouth of the stomach, and let this be healthy; for B, that is, for the food not to rise, appears to be present with walking, C, and with this A, salubrious. What then is the cause that A, which is that for the sake of which (the final cause), is present with C? B (is the cause), that is, the food not rising, this however is as it were, the definition of it, for A will be thus explained. Why is B present with C? because to be thus affected is to be well: we must nevertheless change the sentences, and thus the several points will be more clear. The generations here indeed, and in causes respecting motion, subsist vice versâ, for there it is necessary that the middle should be first generated, but here C, which is the last, and that for the sake of which is generated the last.
Possibly indeed the same thing; may be for the sake of something, and from necessity; for instance, why does light pass through a lantern? for necessarily that which consists of smaller particles passes through larger pores, if light is produced by transit, also (it does so) on account of something, that we may not fall. If then it possibly may be, is it also possible to be generated?
