Democritus (c. 460-370)

§From Abdera, coast of Thrace

§Taught by Leucippus

§Identified indivisible atoms and a void with the basic entities.

Atomism…

Responds to Parmenides’ denial of non-being by maintaining that atoms cannot come to be
or be destroyed.

Fragment 4…

“Leucippus postulated atoms and void, and in this Democritus resembled him.”

From Simplicius, Frag. 18

“They (Leucipus, Democritus, Epicurus) said that the first principles were infinite in number, and thought they were indivisible atoms and impassible owing to their compactness, and without any void in them; divisibility comes about because of the void in compound bodies.”

Democritus’ Atoms

§Are infinite in number

§Have the same
physical nature

§Are indivisible

§Vary in shape, arrangement,
and position

From Aristotle,
Metaphysics

“These men… say the
differences in atoms are
the causes of other things.
They hold that these differences are three – shape, arrangement, and position.”

Democritus also
argues that…

Sheer nothingness or Void exists.

Democritus claims that the existence of “Void” is necessary to
explain how:

§There can be an infinite
number of atoms.

§Single atoms are indivisible.

§Atoms can move about,
and thereby, combine with
one another.

From Aristotle’s Physics
(Frag. 67A10)

“They say that there would be no change in place
(i.e. motion and growth), since motion would not seem to exist, if there were no void, since what is full cannot admit anything.”

Fragment 6

“They move in a void and
when they come together
they cause coming to be,
and when they separate
they cause perishing.”

The Nature of Void

§Aristotle identifies the
atomists’ void with space.

§Other interpreters
maintain that the
void is itself in space.

Whatever its nature,
void is defended by
the atomists on the
grounds that…

§Its existence is required
to explain motion.

§Moreover, “there is no less reason for nothing to be than for something to be”.

With respect to (b)
Parmenides might reply

P1. Knowing is the capacity
for grasping being, that is to say knowing is the capacity for grasping what really is something.

P2. The void is not/ is nothing.

P3. So the void cannot be known.

Hence, (b) is false.
But if (b) is false,
then Being “stays there fixed”. So (a) is also false.

Nevertheless, on the
Atomists’ view…

§Sensible objects arise
from the combination
of atoms.

§Change is due to the rearrangement of the atoms.

And…

All the movements and
interactions of atoms in
the void happen of necessity.
There is no intelligent agency or inherent design in nature.

As Simplicius says…

Atoms, which are separate
from one another in the
unlimited void, move in the void; and when they collide with one another, some become entangled in virtue of their shapes, sizes, arrangement [position] and stay together. This is how compounds are produced.

Atomists, then, like
the other PreSocratic materialists…

§Maintain that the natural
world is fundamentally material, mechanical, and
non-moral.

§Change is entirely due to combination and separation of material parts of things.

Socrates’ Criticism of
Materialist PreSocratics

§In the Phaedo at 96ff,
before Socrates introduces
his own view of formal cause,
he criticizes his predecessors on the topic of how things change.

§Separation and combination cannot fully account for how things change.

He gives 2 cases to weaken the PreSocratic position on change. PreSocratics hold…

§A small person becomes
large by the addition of flesh.

§One unit can become two units either by being added to another unit or by being divided.

With respect to
the second case,
Socrates is puzzled
because…

The units were two before they were added together.
So addition is not
sufficient to explain
coming to be two.

Moreover…

Division cannot fully explain
coming to be two because
it is the opposite of addition. Opposite processes
cannot have the
same result.
Otherwise, the processes
would not be opposite
to one another.

With respect to the
first case…

Socrates says later
in the Phaedo that
“it is monstrous
for a big man to be big
by, or because of,
something small”.
(101, p. 186)

By this I think that
he means…

Whatever explains coming
to have or possess a property,
such as being big, cannot itself possess or have the opposite property, in this case being small, since ultimately this would in a sense be a case of something coming from nothing.

Based on his critique of materialist PreSocratic explanations of change,

§Socrates, as Plato’s
spokesperson, introduces
the idea of a formal cause.

§There are then, in Plato’s view, abstract entities, forms or properties, that enter into an adequate explanation of how things change.