The Vortex Theory of Empedocles (from Anaximander)

Anaximenes and Anaxagoras and Democritus give the flatness of the earth as the cause of its staying still.

It covers the air beneath it like a lid.

The same immobility, they say, is produced by the flatness of the surface which the earth presents to the air which underlies it.

while the air, not having room enough to change its place because it is underneath the earth, stays there in a mass, like the water in the case of the water-clock.

They adduce an amount of evidence to prove that air, when cut off and at rest, can bear a considerable weight.

If the shape of the earth is not flat, its flatness cannot be the cause of its immobility.

But in their own account it is rather the size of the earth than its flatness that causes it to remain at rest.

For the reason why the air is so closely confined that it cannot find a passage.

Therefore it stays where it is, is its great amount.

This amount is great because the body which isolates it, the earth, is very large.

This result, then, will follow, even if the earth is spherical, so long as it retains its size.

My quarrel with them is based on the whole universe.

One must decide at the outset whether bodies have a natural movement or not, whether there is no natural but only constrained movement.

Bodies which have no natural movement have no constrained movement.

Where there is no natural and no constrained movement there will be no movement at all.

But if there is any natural movement, constraint will not be the sole principle of motion or of rest.

If the earth is immobile by constraint, the so-called ‘whirling’ movement by which its parts came together at the centre will also be constrained.

The form of causation supposed they all borrow from observations of liquids and of air, in which the larger and heavier bodies always move to the centre of the whirl.

This is thought by all those who try to generate the heavens to explain why the earth came together at the centre.

Why does the center stay at the center?

Some give the cause as the Earth’s size and flatness.

Empedocles says that the fast motion of the heavens prevents the movement of the earth.

This is like water swirling in a cup not moving down.

But suppose the ‘whirl’ stops.

Where will the earth move to then?

Against Empedocles, I ask: when the elements were separated off by Hate, what caused the earth to keep its place?

Surely the ‘whirl’ cannot have been then also the cause.

The whirling movement might have caused the original coming together of the earth at the centre.

Why do heavy bodies fall to the earth if the whirl of the heavens surely does not come near us?

Why does fire move upward? Surely it is not because of the whirl.

If fire naturally moves in a certain direction, then the Earth moves in a certain direction too.

It cannot be the whirl which determines the heavy and the light.

Rather the whirl caused the pre-existent heavy to fall and light to float.

Thus, heavy and light existed even before the whirl began.

What is the cause of heaviness and lightness?

In the infinite chaos, there can have been neither above nor below, and it is by these that heavy and light are determined.

Among the ancients, Anaximander says that:

• the earth keeps its place because of its indifference.

Motion upward, downward, and sideways were all equally inappropriate to a thing at the centre and indifferently related to every extreme point.

To move in contrary directions at the same time was impossible: so it must needs remain still.

This view is ingenious but not true.

The argument would prove that everything at the centre must stay there.

Fire, then, will rest at the centre. For the proof turns on no peculiar property of earth. But this does not follow.

We observe:

• the earth remaining at the centre
• the earth element moving to the centre

The place to which any fragment of earth moves must necessarily be the place to which the whole moves. *

The reason then is not in the fact that the earth is indifferently related to every extreme point: for this would apply to any body, whereas movement to the centre is peculiar to earth.

It is absurd:

• to look for a reason why the earth remains at the centre
• but not look for a reason why fire remains at the edge

If the edge is the natural place of fire, then the earth must also have a natural place.

It is strange to ask why things stay still but not ask about their motion.

Their statements are not true.

If the Earth is not at the centre, then why does soil and rocks go down towards the center of the Earth?

The argument should apply equally to fire.

If fire is at the centre then why does fire go up away from the center?