I say, then, if you affirm that an animal is what has the power of sensation and of moving itself from appetency, that an animal is not simply what moves through appetency and is possessed of sensation. For it is also capable of sleeping, or, when the objects of sensation are not present, of not exercising the power of sensation. But the natural power of appetency or of sensation is the mark of an animal. For something of this nature is indicated by these things. First, if the fœtus is not capable of sensation or motion from appetency; which is the point proposed for consideration. Another point is; if the fœtus is capable of ever exercising the power of sensation or moving through appetency. In which sense no one makes it a question, since it is evident.