The Milesians on Change

Again, even if it is quite impossible both for what does not exist to come into being and for what exists to perish, why should not some things nevetheless be generated and others eternal as Empedocles says? For he too, having admitted all this –namely thatfrom what does not exist nothing can come into being, and for what exists to be destroyed is impossible and unaccomplishable—

Nevertheless he says that some things are eternal while others come and have come into being from them.

Aristotle, On Melissus

The Stuff View: All that exists is either identical to or constituted by stuff.Atomism: All that exists is either identical to or composed of atoms.

Parmenides’ ArgumentAgainst Generation

1. If something is generated, then either (a) it comes from nothing or (b) it comes from something that already existed.

2. It is impossible that (a).3. It is impossible that (b).4. Everything is ungenerated.

Heraclitus’ Flux Argument

1. A river is a body of flowing water.2. A body of flowing water does not

exist for more than a moment.3. If (1) and (2), then a river does not

exist for more than a moment. 4. If a river doesn’t exist for more than

a moment, then the Doctrine of Flux is true.

5. The Doctrine of Flux is true.

A Milesian Argument for Stuff

1. A body of flowing water does not exist for more than a moment.

2. A river does exist for more than a moment.3. [So] A river is not identical to a body of

flowing water.4. If (3), a river is constituted by a body of

flowing water. 5. If a river is constituted by a body of

flowing water, then the Stuff View is true.6. The Stuff View is true.