John West wrote:

Hi truthseeker,

Would it be correct of me to suppose that, at root, you're asking "What entails that we ought to accept the act/potency distinction?"

Excuse me, I should've been more careful in my reply. Ultimately, I want to know what entails that we ought to accept the act/potency distinction. But thus far in the thread, I just want to know how refuting Parmenides requires that we accept the distinction, and how refuting Zeno requires that we accept the distinction. I would appreciate it if for now we focused on Parmenides' and Zeno's arguments and how they require that we accept the distinction.

Scott wrote:

truthseeker wrote:

1. Everything that changes is changed by something else.
2. Being and only Being exists.
C. Therefore, nothing changes.

This argument is valid.

Only if it's regarded as an enthymeme with the missing premise

3. Being is simple and is not multiplied.

When I wrote 2., I intended 'Being' to be a proper name for the one and only entity. Thus, I understand your 3. to be equivalent to my 2.

Timocrates wrote:

So you believe that from nothing anything and, indeed, everything comes and will follow? 

Do you believe that wood itself and as such can be anything or everything?

No, I believe neither of these propositions. I assume you ask these questions in connection with my rejection of Parmenides's argument providing a compelling reason to accept the act/potency distinction.

Feser, paraphrasing Parmenides, wrote:

(1) Change would require being to arise out of non-being or nothingness.
(2) From non-being or nothingness, nothing can arise.
(C) Therefore, change is impossible.

All one needs to do to refute the argument is choose one of the following: 

~(1) Change would not require being to arise out of non-being or nothingness.
~(2) From non-being or nothingness, something can arise.

Accepting ~(1) seems to me to be the best way to deal with Feser's Parmenides. Here's a scenario that disproves (1): A man covers a hole by pushing a stone in front of it with a stick. The state of affairs of the stone covering the hole is a being. When that being comes into being after not being the case, one can say that that being arises. That being arises out of the man's pushing the stone with the stick, and the man's pushing the stone with the stick is also a being. There is a change here, and the change doesn't involve being arising out of non-being or nothingness. It involves a being arising from another being. I did not have to invoke the act/potency distinction in this scenario, so there are other ways of refuting Parmenides's argument than invoking the act/potency distinction. Thus, the argument doesn't force us to accept the act/potency distinction.

 

Now that we've discussed what potency is, let's discuss why one would adopt the notion. Feser writes that one needs to adopt potency to refute the following arguments:

(1) Change would require being to arise out of non-being or nothingness.
(2) From non-being or nothingness, nothing can arise.
(C) Therefore, change is impossible.

(1') A runner can get from point A to point B only if he first reaches the midpoint between A and B.
(2') He can reach that midpoint only if the first reaches the point midway between A and the midpoint, then the point midway between A and that midpoint, and so on ad infinitum.
(C') Therefore, he can never move beyond A.

Neither of these arguments seem to me to require that one postulate potency. The premises of the first argument are ambiguous, and none of the disambiguations that I can think of necessitate the postulation of potency. The second argument is just invalid. Could someone explain to me why each of these arguments necessitate the postulation of potency?

There are other problematic cases of the sort you mention: Socrates has an essence. Does the essence of Socrates have an essence? If so, does the essence of the essence of Socrates have an essence? These kinds of cases suggest to me that there should either be a limit on that which can have an essence, or that the essence of some beings is identical to them. E.g., the essence of the essence of Socrates would be identical to the essence of Sorates.

What else besides substances have essences?