Book 8
9
For it would seem that the formula which involves the differentiae is that of the form and the actuality, while that which involves the constituent parts is rather that of the matter. The same is true of the kind of definitions which ArchytasA celebrated Pythagorean, contemporary with Plato. used to accept; for they are definitions of the combined matter and form. E.g., what is windlessness? Stillness in a large extent of air; for the air is the matter, and the stillness is the actuality and substance.
10
What is a calm? Levelness of sea. The sea is the material substrate, and the levelness is the actuality or form.
10
From the foregoing account it is clear what sensible substance is, and in what sense it exists; either as matter, or as form and actuality, or thirdly as the combination of the two.
1
We must not fail to realize that sometimes it is doubtful whether a name denotes the composite substance or the actuality and the form—e.g. whether house denotes the composite thing, a covering made of bricks and stones arranged in such-and-such a way, or the actuality and form, a covering; and whether line means duality in length or dualityCf. Aristot. Met. 7.11.6.; and whether animal means a soul in a body or a soul; for the soul is the substance and actuality of some body.
