132 l/-20
Physics
Diogenes Laertius 7.132-160 [11-20]
- They divide the account of physics into topics on bodies and on
principles and elements and gods and limits and place and void. And
this is the detailed division; the general division is into three topics,
concerning the cosmos, concerning the elements and the third on
causal explanation.
They say that the topic concerning the cosmos is divided into two
parts; for the mathematicians share in one branch of its investigations,
the one in which they investigate the fixed stars and the planets, for
example, [to ascertain] whether the sun is as big as it appears to be, and
similarly if the moon is; and concerning the revolution [of the cosmos]
and similar enquiries. - The other branch of the investigation of the cosmos is the one
which pertains only to natural scientists, the one in which the substance
[of the cosmos] is investigated and whether it is generated or ungenerated
and whether it is alive or lifeless and whether it is destructible or inde-
structible and whether it is administered by providence; and so forth.
The topic concerning causal explanations is itself also bipartite. For
medical investigation shares in one branch of its investigations, the one
in which they investigate the leading part of the soul, what happens in
the soul, the [generative] seeds, and questions like these. The mathemati-
cians also lay claim on the other, for example, [investigation into] how
we see, into the cause of how things appear in a mirror, how clouds
are formed, and thunder and rainbows and the halo and comets and
similar topics. - They believe that there are two principles of the universe, the
active and the passive. The passive, then, is unqualified substance, i.e.,
matter, while the active is the rational principle [logos] in it, i.e., god.
For he, being eternal and [penetrating] all of matter, is the craftsman of
all things. Zeno of Citium propounds this doctrine in his On Substance,
Cleanthes in his On Atoms, Chrysippus towards the end of book one of
his Physics, Archedemus in his On Elements and Posidonius in book two
of his Account of Physics. They say that there is a difference between
principles and elements. For the former are ungenerated and indestructi-
ble, while the elements are destroyed in the [universal] conflagration.
And the principles are bodies^20 and without form, while the elements are
endowed with form. - So the mss; some editors prefer the emendation "incorporeal".