Causes are spoken of in a number of ways. In one way, then, that out of which a thing comes about and which is immanent, is called cause, e.g. the bronze of the statue, the stone of the house, and the genera of these.
The form
In another, the form and the exemplar (archetype) are called causes; that is, the statement of the essence of a thing (the definition), and its genera; for example, for an octave, the ratio 2 to 1, and in general the number and the parts in its definition.
The first origin of a change
Again, whence the first origin of a change or of a standstill; for example, the man who gave advice is a cause, the father is cause of the child, and in general what makes of what is made and what causes change of what is changed.
The end
Moreover, the end (purpose); that is, the final cause, e.g. health is the cause of walking. For why does one walk? We say ‘τo be healthy’, and in speaking thus we think we have given the cause.
Also, whatsoever is changed by something else and comes about as an intermediate step towards the end, e.g. thinning or purging or drugs or instruments do come about for the sake of health; for all these are for the sake of the end, but they differ from one another in that some are actions, others instruments.
Bibliography: Aristotle Physics (194b.23)
Translation – text editing: George Kotsalis