ML wrote:

Timocrates,

"Please remember the maxim - especially important for physics - that from nothing comes nothing."

I agree that nothing comes from nothing, but I'm not suggesting that the apple's greenness came from nowhere - I think that's metaphysically impossible. I'm suggesting that there's no need to speak of "coming from" at all. The apple was red at t1, and green at t2 (because of this or that cause), and that's all there is to it. It seems gratuitous to speak of a "coming-from" event here.

I agree that the apple had a capacity to be green, and that the apple was potentially green, but I don't see how this shows that we need to posit another mode of existence (potential existence). To say that X potentially exists isn't to commit oneself to a realm of potential existence - it's merely to say that X can exist, or it's possible for X to exist. (Possibility can be cashed out in different ways; my preferred account is Pruss's causal account - roughly, X is possible iff either X or something can cause X.)

Perhaps I'm confusing something here though 
 

Well, right off the bat you have a problem:

"To say that X potentially exists isn't to commit oneself to a realm of potential existence - it's merely to say that X can exist, or it's possible for X to exist."

Which means you actually are committed to a realm of potential existents. Nothing cannot exist. Therefore whatever can exist can't be nothing. But if it is not nothing, then it is something. But how can something be something even if we can't say it is or exists? How do we resolve this without claiming that these things are nothing, which cannot exist? Or how do we say they are something without making them to also necessarily exist?

I think ML the problem that generates is that at some point you have to draw the line between something and nothing. To say that the green is because of a cause but previously did not exist raises at least two issues, I suspect:

1. How do we explain the greenness before it existed to when it existed, without alluding to potency or act? What, if anything, was or is the difference?

2. What about situations where things perfectly possible are, notwithstanding, not possible for a given thing to be or become?

For example, an apple can be or become green, say, but it can't be or become musical or a builder. A man, however, can. But this doesn't mean builders or musicians are themselves impossible because apples can't be or become them. It is, however (presumably), not possible for apples to be or become musicians or builders; that is, impossible for apples.

Further, we seem to get into the problem of unexercised capacities. So, for instance, if a man has his eyes shut, then he is not seeing; however, we do not say the man cannot see, which would be to say he is blind. We say instead that he is still capable of seeing; and again if he is a musician not making music or a builder not building. One consequence (traditionally) of denying the meaningful reality and metaphysical necessity of potency was inevitable problems such as these, which could be multiplied almost ad infinitum.

Last edited by Timocrates (2/17/2016 11:51 am)

Just following on briefly to Timocrates's and John's posts:

ML wrote:

What I find mysterious is the supposed difference between non-existence and non-actual existence. Somehow, it seems Thomists claim the two are distinct, but I honestly can't see any difference between the two.

The greenness of the red apple is existent but non-actual; it isn't green now, but it has a potency to become green, and this potency (power, capacity) belongs to the apple itself -- now, even before it becomes green (if it ever does) -- so there's a sort of "latent greenness" present virtually in that power. The musical skills of the apple, by contrast, are non-existent.

(Strictly speaking, even God can't make an apple that has musical skills, because a substance with such skills couldn't have the nature of an apple (i.e., the real thing we call an "apple" in our world, not some other thing to which we might apply the word in some other world). So strictly speaking that's not logically or metaphysically possible either. If you want an example of a metaphysical possibility that isn't a potency, a possible example is the yellowness of the same apple. Assuming it has no inherent, natural potency/power/capacity to (be) turn(ed) yellow, nevertheless there seems to be no reason why e.g. God couldn't turn it yellow by direct intervention without violating or changing its nature.)

I'd never thought about capacity and quantity like that. Thanks Timocrates.

Dennis wrote:

Scott, John, and Timocrates, I'll come back with my problems about reductionism and Act/Potency a bit later.

Looking forward to it, Dennis!

Scott,

"Suppose the apple has a disposition to turn green. Now, this isn't just any old disposition, ready to be turned willy-nilly upon this or that end; it's a disposition to turn green, and so greenness must surely be in some way involved in its very nature."

This is also really helpful! I'm still trying to wrap my head around the idea, but I think this addresses one of my main issues with the idea of potency.