Editing Hylomorphism (section)

===Basic theory===
{{See also|On the Soul|Aristotle's biology}}
Aristotle applies his theory of hylomorphism [[Aristotle's biology|to living things]]. He defines a [[Soul (spirit)|soul]] as that which makes a living thing alive.<ref>''On the Soul'' 413a20-21</ref> Life is a property of living things, just as knowledge and health are.<ref>''On the Soul'' 414a3-9</ref> Therefore, a soul is a form—that is, a specifying principle or cause—of a living thing.<ref>''On the Soul'' 412a20, 414a15-18</ref> Furthermore, Aristotle says that a soul is related to its body as form to matter.<ref>''On the Soul'' 412b5-7, 413a1-3, 414a15-18</ref>

Hence, Aristotle argues, there is no problem in explaining the unity of body and soul, just as there is no problem in explaining the unity of wax and its shape.<ref>412b5-6</ref> Just as a wax object consists of wax with a certain shape, so a living organism consists of  a body with the property of life, which is its soul. On the basis of his hylomorphic theory, Aristotle rejects the [[Pythagoreanism|Pythagorean]] doctrine of [[metempsychosis]], ridiculing the notion that just any soul could inhabit just any body.<ref>''On the Soul'' 407b20-24, 414a22-24</ref>

According to Timothy Robinson, it is unclear whether Aristotle identifies the soul with the body's structure.<ref>Robinson 45-47</ref> According to one interpretation of Aristotle, a properly organized body is already alive simply by virtue of its structure.<ref name="Robinson 46">Robinson 46</ref> However, according to another interpretation, the property of life—that is, the soul—is something in addition to the body's structure. Robinson uses the analogy of a car to explain this second interpretation. A running car is running not only because of its structure but also because of the activity in its engine.<ref name="Robinson 46"/> Likewise, according to this second interpretation, a living body is alive not only because of its structure but also because of an additional property: the soul, which a properly organized body needs in order to be alive.<ref>Robinson 47</ref> John Vella uses [[Frankenstein's monster]] to illustrate the second interpretation:<ref>Vella 92</ref> the corpse lying on Frankenstein's table is already a fully organized human body, but it is not yet alive; when Frankenstein activates his machine, the corpse gains a new property, the property of life, which Aristotle would call the soul.