Miscellanies 8.4.13

Nor, indeed, is what is signified by the name “what is conceived” an animal; that is incorporeal, a sayable, a matter, a thought, and anything rather than an animal. The nature of the animal would be something else; for it was clearly shown to belong to the very thing under inquiry, I mean the nature of the embryo, what sort it is, while the question about what is signified by the name “animal” is a different problem. I say, then: if you call an animal that which can perceive and move by impulse, an animal is not simply what is moving by impulse and perceiving (for it can also sleep, or not perceive when objects of sense are not present); rather, what is naturally able to exercise impulse or also to perceive is the mark of an animal. For something of this sort is signified by these words. First, whether what is conceived can already perceive or move by impulse, which is what is proposed for examination. Second, whether what is conceived will at some time be able to perceive or move by impulse, a sense in which no one inquires, since it is evident. The question was whether the embryo is already an animal or still a plant. And then the name “animal” was translated into an account, so that it might be clear, since we found that it differs from what is not an animal by perception and by motion according to impulse. Again, we distinguished this from the things adjacent to it, saying that one thing is what is such potentially, which is not yet perceiving and moving but will at some time be such, and another is what is already such in actuality; and of the latter, one is already active, while another can be active but is at rest or asleep. It is this that is under inquiry. For the embryo is not to be called an animal because it is nourished; that is the view of those who depart from the essence of what is sought and turn their attention to what is otherwise incidental.