A compound word composed of the Greek terms for matter (hulê) and form (morphê), hylomorphism refers to Aristotle's view of body-soul and matter-form relations.

He explains the connection between body and soul most extensively in De Anima: "We will say that the soul is the first actuality of a natural organic body."1 Body-soul relations are a specific example of a more general relationship that exists between all compounds, natural or artificial, and their respective forms.

In order to better understand the relationship between these two fundamental elements of Aristotle's theory, it is necessary to grasp the meaning of the terms themselves. Hylomorphism can only be understood in the greater context of Aristotle's theory of causation. In order to fully understand everything about a particular material object, there are four factors which must be known. The object's matter itself, its form or structure, the agent responsible for that object having that particular form, and the specific purpose that the matter was made into that form. These factors are called Aristotle's Four Causes (aitiai).

The issue of the body and soul raises some quesitons about the unity of these elements. Materialism contends that mental states are also physical states, which is contrary to a dualist position, which is that mental states can exist alone. Aristotle addresses this issue in De Anima:

"Hence we need not ask whether the soul and body are one, any more than we need to ask this about the wax and the shape, or, in general, about the matter and the thing of which it is the matter. For while one and being are spoken of in several ways, the actuality and what it actualizes are fully one. 2

Aristotle is not dismissing the importance of such an understanding of unity, rather, he is taking it as self-evident and axiomatic. Neither is he stating that they are identical, in fact, he explicitly denies this fact. 3

An interesting implication of this theory is that if hylomorphism applies without reservation to the human soul-body, then there is no reason to assume that the soul will somehow separate from the body upon death and continue to exist. Aristotle makes exceptions on this point, stating that there are indeed parts of the soul that may endure beyond death:

"It is clear, then, that the soul is not separable from the body. At least, some parts of it are not, if it is divisible into parts; for the actuality of some parts of the soul is the actuality of the parts of the body themselves." 4

Here Aristotle makes an allowance for his conception of the mind (nous), which is complex in that he describes it as being the most exceptional capacity of the soul.

The most important thing to understand about Aristotelian hylomorphism is that he believes that all physical matter has a potential to be something, and the form of an object is the actuality of that physical material. Because of this, there evolves a relationship between objects and their structures.


1Aristotle. De Anima. ii 412b 4-5.
2ii 412b 6-9.
3ii 412a 18.
4ii 413a 4-7.