On Generation and corruption
thus expressed, is itself open to criticism. Things which come-to-be
and pass-away cannot be called by the name of the material out of
which they have come-tobe: it is only the results of 'alteration'
which retain the name of the substratum whose 'alterations' they
are. However, he actually says' that the truest account is to affirm
that each of them is "gold"'.) Nevertheless he carries his analysis of
the 'elements'-solids though they are-back to 'planes', and it is
impossible for 'the Nurse' (i.e. the primary matter) to be identical
with 'the planes'.
Our own doctrine is that although there is a matter of the
perceptible bodies (a matter out of which the so-called 'clements'
come-to-be), it has no separate existence, but is always bound up with
a contrariety. A more precise account of these presuppositions has
been given in another work': we must, however, give a detailed
explanation of the primary bodies as well, since they too are
similarly derived from the matter. We must reckon as an 'originative
source' and as 'primary' the matter which underlies, though it is
inseparable from, the contrary qualities: for the hot' is not matter
for 'the cold' nor 'the cold' for 'the hot', but the substratum is
matter for them both. We therefore have to recognize three
'originative sources': firstly that which potentially perceptible
body, secondly the contrarieties (I mean, e.g. heat and cold), and
thirdly Fire, Water, and the like. Only 'thirdly', however: for
these bodies change into one another (they are not immutable as
Empedocles and other thinkers assert, since 'alteration' would then
have been impossible), whereas the contrarieties do not change.
Nevertheless, even so the question remains: What sorts of
contrarieties, and how many of them, are to be accounted
'originative sources' of body? For all the other thinkers assume and
use them without explaining why they are these or why they are just so