Changes

The first text illustrates the use of this distinction in the context of a psychological investigation.

The first text illustrates the use of this distinction in the context of a psychological investigation.

<pre>

We describe one class of existing things as substance (ousia);  and this we subdivide into three:  (1) matter (hyle), which in itself is not an individual thing;  (2) shape (morphe) or form (eidos), in virtue of which individuality is directly attributed;  and (3) the compound of the two.

<p>We describe one class of existing things as substance (''ousia'');  and this we subdivide into three:  (1) matter (''hyle''), which in itself is not an individual thing;  (2) shape (''morphe'') or form (''eidos''), in virtue of which individuality is directly attributed;  and (3) the compound of the two.</p>

Matter is potentiality (dynamis), while form is realization or actuality (entelecheia), and the word actuality is used in two senses, illustrated by the possession of knowledge (episteme) and the exercise of it (theorein).

<p>Matter is potentiality (''dynamis''), while form is realization or actuality (''entelecheia''), and the word actuality is used in two senses, illustrated by the possession of knowledge (''episteme'') and the exercise of it (''theorein'').</p>

Bodies seem to be pre eminently substances, and most particularly those which are of natural origin;  for these are the sources from which the rest are derived.

<p>Bodies seem to be pre-eminently substances, and most particularly those which are of natural origin;  for these are the sources from which the rest are derived.</p>

But of natural bodies some have life and some have not;  by life we mean the capacity for self sustenance, growth, and decay.  Every natural body, then, which possesses life must be substance, and substance of the compound type.

<p>But of natural bodies some have life and some have not;  by life we mean the capacity for self sustenance, growth, and decay.  Every natural body, then, which possesses life must be substance, and substance of the compound type.</p>

But since it is a body of a definite kind, viz., having life, the body cannot be soul, for the body is not something predicated of a subject, but rather is itself to be regarded as a subject, i.e., as matter.

<p>But since it is a body of a definite kind, viz., having life, the body cannot be soul, for the body is not something predicated of a subject, but rather is itself to be regarded as a subject, i.e., as matter.</p>

So the soul (psyche) must be substance (ousia) in the sense of being the form (eidos) of a natural body (soma), which potentially (dynamei) has life.  And substance in this sense is actuality (entelecheia).

<p>So the soul (''psyche'') must be substance (''ousia''') in the sense of being the form (''eidos'') of a natural body (''soma''), which potentially (''dynamei'') has life.  And substance in this sense is actuality (''entelecheia'').</p>

Aristotle, De Anima, II.i.412a6-412a22

| align="right" | Aristotle, ''De Anima'', II.i.412^a6&ndash;412^a22

The soul, then, is the actuality of the kind of body we have just described.  But actuality has two senses, analogous to the possession of knowledge and the exercise of it.

The soul, then, is the actuality of the kind of body we have just described.  But actuality has two senses, analogous to the possession of knowledge and the exercise of it.