@bmiller: hello here is more of a response to yours. 

I suggest the issue includes one of methodology in interpretation: what evidence is needed for a claim that an author means to assert P in a passage where he does not state P? I.e. how to get from Aquinas' prologue to his comm on Gen/Corr to his meaning in the First Way.


I see at least five questions, or something like these, about gen/corr and motion (kinesis): 
a. what did Aristotle hold at what place in his writings?
b. do today’s scientists and/or philosophers think his conclusions correct?
c. what did Aquinas think Aristotle meant in this or that passage?
d. what did Aquinas understand by "motion" in the First Way?
e. do today’s scientists and philosophers think his conclusions correct?

I'll only try to reply re a. and c.

a. We've agreed previously that Aristotle speaks of gen /corr as "motions" in places in GC, esp. at the outset. As he goes along in Bk. I, he distinguishes between genesis "simply" and genesis, or change coming to be, "with respect to a part", I.3, 317b35. This distinction is repeated at 318a28-29 and elaborated in the ensuing lines, so that "the way into not being simplicter is simple destruction, and the way into being simpliciter is generation.” This distinction then gets cashed out as genesis/destruction simply on one hand and gen/corr of a certain kind on the other. The latter amounts to locomotion, alteration and growth/decay (319a12). Thus there are four changes, “metabolai”: gen/corr, loco, alt, growth/decay. In I.4, the distinction between change in substance and change in quality (eidos), or alteration, is set out somewhat more precisely, but not as clearly as in Physics V ff. As Hans Joachim says in his commentary on GC, “Aristotle’s usual practice is to draw a sharp distinction between the three [here follows Greek, which I translate] forms of motion (kinesis) (alteration, growth/decay and locomotion) and generation and corruption, and to use the term “change” (metabole) to cover all forms of change (i.e. genesis and corruption as well as the three species of kinesis)… But this practice is by no means invariable (94-95) … But linguistic usage appears to conflict with the theory (98).”
     At I.4 319b6-18, Aristotle sets out the theoretical basis of his distinction between gen/corr and other kinds of change. Alteration is a change in an attribute of a substrate/subject, when the subject remains and is perceptible, and the change is between contraries or intermediates, as in becoming healthy from sick, or bronze’s being shaped differently. When the entire substance changes and the subject does not remain, as when all the semen becomes blood or all the water becomes air, this is genesis or destruction.
     Note that the argument to support the distinction betw gen/corr and the other changes is the same argument as we get in Physics V: that alteration etc is between contraries or intermediates, but change of substance, gen/corr, is between contradictories. In Phys Ari adds the reason: that a substance does not have a contrary, only a contradictory (a man can be destroyed into not-man, but there is no contrary of man). That argument appears in shorter form in De Caelo IV.3, 310a22-29. There Ari says that there are other geneseis and changes (metabolas), but since there are three motions, we see that in each of them there is a change that occurs from opposites to opposites and intermediate stages.
    By the end of GenCorr , Ari sets genesis and kinesis parallel as though they are different (318a-b), but he does not spell this out. He continues to try to show that motion is also a condition for change of substance, since something moves in place when a subject is generated or destroyed, and prime matter—not a substance, of course--remains as a substrate. The best I can do at this point is to think that Ari has the conception in GenCorr of the distinction between gen/corr and what he elsewhere calls “motion in the strict sense.” But he does not harmonize his terminology completely between this work and the latter part of the Physics or the summary in De Caelo.
 
c. Aquinas himself only commented on Book I of the GenCorr. When he gets to passages like those above, he does make clear that on Ari’s view, there is a difference betw change of subject, “simple” gen/corr, and changes of properties of a subject. The section numbers differ in this translation from the section numbers in the Latin. But cf. e.g. from lectio 2:
“12. He says therefore first [11] that all the philosophers who assert that all things are produced from one material principle are forced to say that generation and corruption are the same as alteration. [snip] Now we say that a thing is altered when, with the substance of the thing in act remaining, some variation occurs with respect to the form. Hence it follows that there can be no change called simple generation and corruption, but only alteration.
We, on the other hand, declare that there is of all generable and corruptible things one first subject, which, however, is not a being in act but in potency. Therefore when its first subject acquires a form through which it becomes a being in act, this is called simple generation. But it is said to be altered when, after being made a being in act, it acquires any additional form.”
From lectio 10:
 “79. Then [76] he shows, from the side of the subject, how generation differs from alteration and from other changes.
First, he shows how all of them are related to the subject which is a being in act;
Secondly, how related to the subject which is a being in potency, at 81.
He says therefore first [76] that, as was said, alteration is according to the passions of something that remains. And this same thing occurs in other changes, which take place with respect to accidents which occur to a subject existing in act. When, therefore, a change is from contrary to contrary according to quantity — for example, from large to small, or vice versa — we have "growth" or "decrease" of the same permanent subject, since quantity occurs to a subject existing in act. But when the change is with respect to contrariety of place — for example, up or down — it is "latio," i.e., local motion, of the same remaining body, since "where" accrues to a body existing in act. When the change is with respect to a contrariety in passions (i.e., primarily in passible qualities, and in other qualities as a consequence), we have "alteration" of the same permanent being, because quality too accrues to a subject existing in act. But when nothing remains existing in act, of which that which is changed might be a passion or some accident, it is universally "generation and corruption," since the substantial form, with respect to which generation and corruption occur, does not accrue to a subject existing in act.”
 
This is all I’ll cite, since this post is already too long. I think it’s clear that despite Ari’s terminological issues, his distinction between change in substance and change in attributes is clear in Gen Corr. And I think it’s clear that Aquinas recognizes it. It refers to the same bifurcation among changes as does Ari's distinction between species of kinesis vs. gen/corr.
 

Last edited by ficino (12/22/2017 12:27 pm)

Dominican Thomist, Thomas of Sutton (c. 1250-1315) in Part 2 of his On the Plurality of Forms expounds Aristotle's bifurcation of change into generation/corruption vs. kinds of alteration. Among the arguments he gives, Sutton summarizes two of Ari's arguments: that the subject does not persist in a change of substance; that motion is between contraries or intermediates, but gen/corr is between contradictories, since a substance has no contrary, so that gen/corr is not motion.  I haven't found a translation, but the Latin is here:

http://www.corpusthomisticum.org/xpf0.html

Last edited by ficino (12/22/2017 1:16 pm)

Well, while Aquinas did explicitly differentiate between essence and existence, Aristotle did say that things have their being through their essence. Hence if anything essential to a thing's being is negated it ceases to exist.

You've been told repeatedly that Feser does not deny EI. Pay absolutely no attention to SP if you don't want to look foolish.

Feser in no way fundamentally changes the First Way. He doesn't collapse it into the second way because he remains primarily concerned with the distinction between act and potency. This is,again, also why all this exegesis about what counts as motion is irrelevant. The first way begins with observed motion and then moves to the concepts of act and potency. 

Jeremy Taylor wrote:

You've been told repeatedly that Feser does not deny EI. Pay absolutely no attention to SP if you don't want to look foolish.

Feser in no way fundamentally changes the First Way. He doesn't collapse it into the second way because he remains primarily concerned with the distinction between act and potency. This is,again, also why all this exegesis about what counts as motion is irrelevant. The first way begins with observed motion and then moves to the concepts of act and potency. 

I wrote a pacific reply, and then I said to myself, this forum is a joke. I thought there were people here who were interested in discussing writings of classical theists. But no one or almost no one wants to do anything scholarly on here. This place is a claque-pit for Feser. I'm done.