Is the theory (originating with Aristotle (322 BC) that all things are a combination of matter and form.
Aristotle was one of the first ancient writers to approach the subject of life in a scientific way. Biology was one of his main interests, and there is extensive biological material in his extant writings. According to him, all things in the material universe have both matter and form.
The form of a living thing is its soul (Greek ‘psyche’, Latin ‘anima’).
There are three kinds of souls: the ‘vegetative soul’ of plants, which causes them to grow and decay and nourish themselves, but does not cause motion and sensation; the ‘animal soul’ which causes animals to move and feel; and the rational soul which is the source of consciousness and reasoning which (Aristotle believed) is found only in man.
Each higher soul has all the attributes of the lower one. Aristotle believed that while matter can exist without form, form cannot exist without matter, and therefore the soul cannot exist without the body.