of Empedocles, and of his
successors, Anaxagoras, and the Atomists.

Now the Ionic philosophers had taught that all things are composed of
some one ultimate matter. Thales believed it to be water, Anaximenes
air. This necessarily involved that the ultimate kind of matter must
be capable of transformation into other kinds of matter. If it is
water, then water must be capable of turning into brass, wood, iron,
air, or whatever other kind of matter exists. And the same thing
applies to the air of Anaximenes. Parmenides, however, had taught that
whatever is, remains always the same, no change or transformation
being possible. Empedocles here too follows Parmenides, and interprets
his doctrine in his own way. One kind of matter, he thinks, can never
change into another kind of matter; fire never becomes {83} water, nor
does earth ever become air. This leads Empedocles at once to a
doctrine of elements. The word "elements," indeed, is of later
invention, and Empedocles speaks of the elements as "the roots of
all." There are four elements, earth, air, fire, and water. Empedocles
was therefore the originator of the familiar classification of the
four elements. All other kinds of matter are to be explained as
mixtures, in various proportions, of these four. Thus all origination
and decease, as well as the differential qualities of certain kinds of
matter, are now explained by the mixing and unmixing of the four
elements. All becoming is simply composition and decomposition.

But the coming together and separation of the elements involves the
movement of particles, and to explain this there must exist some
moving force. The Ionic philosophers had assumed that matter has the
power or force required for movement immanent in itself. The air of
Anaximenes, of its own inherent power, transforms itself into other
kinds of matter. This doctrine Empedocles rejects. Matter is for him
absolutely dead and lifeless, without any principle of motion in
itself. There is, therefore, only one remaining possibility. Forces
acting upon matter from the outside must be assumed. And as the two
essential processes of the world, mixing and unmixing, are opposite in
character, so there must be two opposite forces. These he calls by the
names Love and Hate, or Harmony and Discord. Though these terms may
have an idealistic sound, Empedocles conceives them as entirely
physical and material forces. But he identifies the attractions and
repulsions of human