Plantinga and Aquinas on the Viability of the ‘Third Way’

Round 1

Reviewer 1 Report

While there is much to like in “Plantinga and Aquinas on the Viability of the ‘Third Way’”, in my opinion it does not add sufficiently to the literature already available on the Third Way. 

 

The paper contains five sections: in the first the author provides some necessary background on Aquinas’s metaphysics, in the second the author explains the Third Way, in the third Plantinga’s criticism of the Third Way is discussed, in the fourth section the author attempts to reply to Plantinga’s criticisms, and in the fifth section the author considers two further challenges Plantinga might raise for Aquinas. There are already many analyses of the Third Way available in print, and Plantinga’s own criticism are found in his book God and Other minds, so the first, second, and third sections are useful only as preparation for the fourth and fifth. Unfortunately, in the fourth section the author fails to give a strong response to Plantinga. Among other challenges, Plantinga objects to two steps in the Third Way, namely:

 

(2)        Whatever can fail to exist at some time does not exist, 

 

and

 

(3)        If all beings are contingent then at one time nothing existed. 

 

In the Third Way (2) is a premise, and (3) is an intermediate step that is supposed to follow from (2). Plantinga thinks that (2) is not self-evident, and that (3) does not follow from (2). 

 

I think the author is correct in arguing that Plantinga misunderstands what Aquinas meant by a necessary being in this argument. (On this issue, see Gregory Robson, “Reconsidering the Necessary Beings of Aquinas’s Third Way,” European Journal for Philosophy of Religion 4:1 (2012): 219-241.) However, the author does not give convincing replies to Plantinga’s objections to (2) and (3). 

 

In response to Plantinga’s criticism that (2) is not self-evident, the author responds by asserting that “Once a person understands the metaphysics behind the argument, these premises are evident.” More work needs to be done here, to have a strong reply to Plantinga. Perhaps the idea is that any given one of the beings discussed in (2) – those that are generable and corruptible, hence hylomorphic compounds – will at some point have its matter refashioned in such a way that the compound ceases to exist. But this does not seem necessarily true. What precludes the possibility that some elemental hylomorphic compound is never actually acted upon in such a way that it is corrupted? Wouldn’t it be possible for God to create a proton from the beginning of time, or from all eternity, and place it somewhere such that it was never acted upon in any way, so that it continued in existence for ever? Indeed, at ST I.46.2 ad 1, Aquinas seems to concede that the eternal God could have, if He had so willed, created a beginningless world. But if he could do that, couldn’t he create a proton from all eternity, and preserve it for all eternity? But then we would have a contingent being that exists at all times.

 

The author’s reply to Plantinga’s objection to the inference from (2) to (3) is given on p. 9, lines 346 – 359, and relies on the argument that “All possible beings must be composed prior to their existing. Therefore, due to the impossibility of an infinite regress, if all are composed, possible beings, then at one time nothing existed” (lines 357-359). I don’t see that the author has convincingly ruled out the possibility of an infinite series of possible beings, one causing the next, ad infinitum. (Aquinas discusses such a series at ST I.46.2 ad 7, admitting the possibility of a certain sort of infinite series.) I think an argument can be made here to rule such a series out: namely, if an infinite series of possible beings is all there is, we will be left with no explanation of why there is such an infinite series at all, rather than there being no such series. While each member of the series will have a causal explanation, there will be no explanation of why reality has contained the infinite series rather than not. But the author doesn’t give that or any other argument to substantiate the idea that there can be no infinite regress here. 

 

Furthermore, there is already a large literature on the inference to (3) and objections to it (Brian Davies, Antony Kenny, Jacques Maritain, C. F. J. Martin and John Wippel all discuss it in their treatments of the Third Way). But that literature is not taken into account in this paper. 

 

The author should be congratulated for some thoughtful work on Plantinga and Aquinas’s Third Way, but to warrant publication I think the paper would have to add more to the already voluminous literature on the Third Way. 

 

Author Response

Thanks for the comments. 

I've rewritten the paper to address the following criticisms:

Quantifier-shift fallacy- Two points to note on this. First, I'm following a charitable reading of Aquinas in the third way that assumes he doesn't commit this fallacy. Many Thomists like Edward Feser do the same. One need not interpret his argument as committing the fallacy. Second, I've explained the metaphysical basis for the argument that calls for the current existence of God based on the current existence of any possible being. I do this in opposition to the idea of existential inertia. I have unpacked this in more clarity in my rewrite. 

I've also rewritten parts of the paper to strengthen my response to the criticisms the reviewer had of weakness of argument. In doing so, I've included the metaphysical analysis of Norman Kretzmann, George Klubertanz's explanation of the philosophy of being, and unpacked the third way as a type of contingency argument. As part of this effort, I've tried to explain not only how the third way succeeds, but how a metaphysical understanding of it implies the attributes of God in the chapters that follow the five ways. 

The third point that I think this metaphysical understanding of the third way answers, and I've tried to make this more explicit with the rewrite, is that this explains why there can't be an infinite series of possible beings. Copleston explains it as the difference between Aquinas's vertical series or as I try to explain it an essentially ordered series and one that is horizontal or accidentally ordered. I've tried to make this more clear. 

Reviewer 2 Report

Please note the following numbered lines and observations regarding them, as well as my overall comments.

While this paper may well be essentially correct and well done regarding its criticism of Plantinga, my problem with it is that I believe it fails to present the argument of the Third Way in a way that comports with St. Thomas’s own wording. St. Thomas's argument begins with things subject to generation and corruption, not with things having an essence/existence composition, as the author emphasizes. In so doing, the author then misses the point that St. Thomas makes a division between possible beings and necessary beings, which latter might NOT be God. That is the point of St. Thomas addressing the possibility of an infinite regress among necessary beings whose necessity is from another. In other words, the Third Way is a two step argument: (1) from the possible to the necessary, and (2) from the necessary whose necessity is from another to God, who alone is necessary per se.

Here is another citation from St. Thomas in the author's own footnote 12 that makes my point: " Every necessary being, however, either has the cause of its necessity in an outside source or, if it does not, it is necessary through itself. But one cannot proceed to infinity among necessary beings the cause of whose necessity lies in an outside source." (SCG I, 15, 5) This shows that necessary beings can have a cause, which means they need not be God.

In a word, while I think the author’s critique of Plantinga might well be acceptable for publication, I do not think the entire paper is acceptable until he corrects his reading and presentation of the Third Way itself. Once that correction is made, the entire paper may be worthy of publication – with other minor noted corrections in the Plantinga section itself.

 

38-39  “ If a person exists (has the act of existence) then as long as they receive this act they lack potential not to exist.”   This appears to me to be factually incorrect.  The precise concept of potentiality is that which could be, but is not.  A creature receives the act of existence from God, but it still could cease to exist if God withdrew his creative causality. Hence, though existing, it has the potential to cease to exist.

58-63   “For Aquinas, creatures have a real distinction between their existence and essence. One can ask and understand what a creature is without knowing whether it is. One can ask this question because the essence of a creature does not contain its existence. For example, I can tell you what a unicorn is without telling you whether there are any existing unicorns. Further, this distinction also notes that creatures are created as composed of the act of existence and their essence.”  This is a version of the “man and phoenix” argument, which needs defense before acceptance of the real distinction between essence and existence in finite beings. 

But, the Third Way is not based on the essence/existence composition of finite things. Rather, it is founded on the generation and corruption of the possibles. Once it is shown that the possibles depend on something necessary, the second phase of the argument proceeds to demonstrate that things that are necessary through another presuppose the existence of something that is necessary through itself, namely, God.

86  “All created beings are possible beings.”  On the contrary, St. Thomas defines the possibles as such, “since they are found to be generated and to be corrupted” in the very text of the Third Way. Clearly St. Thomas does not hold that “all created beings are possible beings,” since angelic substances are not subject to corruption and, in principle, God could create them without beginning if he chose to will their existence from all eternity.

It is clear then that the Third Way argues from the notion of generation and corruption in which the generation of one thing is the corruption of another.  It does not proceed from the real distinction between essence and existence, since that distinction is not proven in the Third Way and it is possible that a thing composed of essence and existence could exist without any temporal beginning should God so will, whereas what is generated must have a beginning as is argued in the Third Way itself. And, as I just noted, angelic beings are not subject to corruption as St. Thomas clearly says the possibles are.

In a word, the Third Way does not proceed from composition alone, since composition itself need not be temporal in origin -- nor need it entail corruption, whereas, in the case of things generated (which is the actual language of the Third Way), generation always presupposes a beginning in time (which composition alone might not). And we must not forget that angels are neither God nor are they mere possibles, since the possibles are subject to corruption and the angels are not.

92  “A necessary being’s essence is existence.”  This seems to leap over the problem of causal regress among intermediate beings whose necessity is real, but comes from another. Moreover, it short circuits the internal logic of the argument. The Third way actually merely says that necessary things’ necessity is either caused or not. In fact, St. Thomas invokes the principle that it is not possible to have an infinite regress among proper causes when talking about necessary things whose necessity is from another.

106-107  “But it is impossible for these always to exist, for that which can not-be at some time is not.”  This is the English translation of an incorrect uncial, as Eric L. Mascall points out. The correct uncial reads: “Impossibile est autem omnia quae sunt, talia (sc. possibilia esse et non esse).  [For it is impossible for all things which exist to be such, that is, possible to be and not be.] See Mascall, He Who Is, 47-48, footnote.

130-131  “….that which is composed at some time does not exist.”  This also appears false, since God could have created an angelic substance with no beginning in time and no possibility of corruption, and yet, it would be composed of essence and esse.

150-153  In arguing against an infinite causal regress in the Third Way, he argues: “For example, suppose a person jumps out of an airplane only to discover their parachute will not open. This person then grabs onto another man who jumped with him only to find out that the second man’s parachute won’t open either.” This argument construes causality as a temporal regress, whereas St. Thomas employs per se causes in the proofs for God, which causes must all act simultaneously. This is a major error.

234-235  “Logically necessary propositions are propositions whose subject adds nothing to the predicate.”   I think that should read that necessary propositions are ones whose predicate adds nothing to the subject -- the reverse of what is written.

353-355 “Everything that is composed does not exist before being composed. But if everything was composed (possible), then prior to everything being composed there was nothing.” This is the same problem I find throughout the paper, namely, the presumption that the possibles are such because they are composed. That is not St. Thomas’s language. They are possibles because they are generated and corrupted. This speaks the language of hylemorphism, of matter/form composition. God could, in principle, cause angelic beings without beginning – through God’s eternal causation – and yet, such beings, composed of essence and existence, would not have any temporal beginning – or corruption..

The natural flow of the Third Way is from the possibles (generated and corrupted) to the need for necessary beings (beings not generated or corrupted), which derive their necessity from another, and finally, to a Per Se Necessary Being, which is God.

363 “ … the third way demonstrates that there is one necessary being.” NOT in my understanding. It demonstrates the possibility of necessary beings and, as St. Thomas puts it, “Every necessary thing either has its necessity caused by another, or not.” (Third Way) Here St. Thomas explicitly allows that you can have necessary things that are caused by another! So, one need not go directly from the possibles to God, and that is why St. Thomas entertains the question of whether or not it is possible to “proceed to infinity in necessary things which have a cause of their necessity!” (Third Way) And that is why it is fundamentally erroneous to read the Third Way as showing that “the third way demonstrates that there is one necessary being,” as the article maintains.

Between 384 and 385 in Footnote 34  “A necessary being is simple.”  I have just shown that it is possible to have necessary beings that are not simple, that is, they may be composed of essence and existence, and yet, not be generated and corrupted.

Conclusion: The latter portion of this article has merit in its criticism of Plantanga. Still, in order to present itself as a complete and correct argument, there is need for making sure that the exposition of the Third Way is correctly done. This will require some careful rewriting of the part of the article dealing with the Third Way. And, in light of that rewriting, a couple statements in the "Plantanga" portion of the article will also need reformulation -- as per my comments above.

N.B. Since St. Thomas does consider the possibility of "necessary" beings in the Third Way, and since this article also discusses God as being "metaphysically necessary" in a later part of the text, it seems to me that an explanation of the distinction between the two types of "necessary beings" should be offered at some point, probably around line 251, where God is said to be the only being that is "metaphysically necessary." Moreover, any changes in understanding of the correct role of "necessary beings" in the first part of the article should be reflected in any statements made about them in the "Plantanga" section -- so as to avoid all errors.

Author Response

Thanks for your work on this.

I've done an extensive rewrite and incorporated many of your great suggestions and corrections. 

Per the rewrite, I'd want to highlight 3 things. First, I've noted the importance of understanding the third way as an essentially ordered series of causes versus an accidentally ordered series. Second, I've emphasized the idea that right now everything must be sustained in existence against the idea of existential inertia. Third, I've argued for a way to understand angels as necessary effects and not necessary beings per se, but existing only because there is a necessary being sustaining them in existence. 

As you are no doubt aware of the debate regarding interpretation of the third way, I'm following the line of thinking proposed in both Reginald Garrigou-Lagrange and Frederick Copleston. I'm not convinced by some of the other interpretations. 

Reviewer 3 Report

The author of “Plantinga and Aquinas on the Viability of the ‘Third Way’” has written a very good article. It is well researched historically with respect to both Plantinga and Aquinas, and it is carefully reasoned philosophically. I am not yet ready, however, to assent to his conclusion in his “Abstract” that “After reading this article it should be clear that the third way to show God’s existence is plausible and Plantinga’s attacks against it are based on a straw man rather than the substantive argument the Third Way actually is.” Of course, I agree with what he has to say about Plantinga’s treatment of the “necessity” posited by Aquinas. Aquinas was affirming metaphysical, not merely logical, necessity. But I have some difficulty with other parts of his article and invite him to consider the following difficulties, most of which center on his insistence that the “necessary being” could not be nature or creation as a whole and must be a simple and timeless reality that transcends this natural whole. Most of the problems I want to discuss are present in the following quote from the top paragraph on p. 6 (lines 212-219).

 The most important argument against the metaphysical conception of the Third Way, according to Plantinga, is the difficulty that arises from premises 2 (Whatever can fail to exist at some time does not exist) and 3 (If all beings are contingent then at one time nothing existed). This argument is the only one Plantinga mentions. According to Plantinga, these premises are not self-evident, and 3 does not follow from 2. Plantinga concludes that even if this argument does work it does not prove the existence of God, but only the existence of a necessary being which could be the universe.

            Granted again, Plantinga confuses logical and metaphysical necessity, and the author deals well with that. This is the first of his two main objections to “the assertion that the third way only proves the universe and not God (p. 10, lines 360-361). I do not think that the author’s second response succeeds, namely, that the third “argument from possibility or contingency” proves only the contingency of nature, not its necessity, and thus requires the necessity of a divine reality that transcends nature. Plantinga’s view seems to be that the universe as a whole is itself the necessary (eternal or everlasting and uncreated) reality. The author’s position is indeed that “If all beings are contingent then at one time nothing existed,” and “If all beings are contingent then at one time nothing existed.” Here are some problems with this that I hope this author will consider.

             Atheistic naturalists and Plantinga could maintain, to the contrary, that the natural universe is composed entirely of contingent individuals, but the whole has nevertheless existed everlastingly and thus necessarily without a cause beyond itself, so it is simply not true that “at one time nothing existed” if all the parts once never existed.

            1. Interestingly, Aquinas himself held that reason alone cannot disprove Aristotle’s view that the universe has co-existed everlastingly with God. This does indeed concede that it is not true that “at one time nothing existed.” Rational philosophy says that the universe as a whole has always existed, even if none of its parts have always existed—even though Aristotle thought that some of them might have.) (Revelation says that nothing other than God existed in the time before time began, but reason cannot show this, Aquinas held.) Is the author claiming that reason can indeed “prove” what revelation only has revealed?

            2. A rather common objection to the “third way” recognizes that this argument from contingency argues that the whole of nature exists only contingently because each of its parts exists only contingently (once never existed and had a cause beyond themselves). The objection is that this argument commits the logical fallacy of composition. This fallacy says that we cannot logically conclude that a given whole (e.g. nature) has a certain property (contingency) merely because each of its parts has that property (contingency). Thus nature as a whole could be necessary (everlasting, uncreated, unchanging) even if each of its parts is contingent (i.e., is not everlasting, uncreated, and unchanging). How would this author respond to this “fallacy of composition” objection?

            3. There are some difficulties with the MEANING of “once” or “before” in “once never existed” or “before they (all of them) existed” that I will not further explore, but this does require more analysis.

            4. The author argues that only a simple and fully actualized reality could be a necessary being (p. 9, lines 366-368ff), that the universe is neither, and concludes that the universe could not be the necessary being. Being “simple” seems to mean that there is only one of them (footnote 34), but the naturalist typically holds, as did Plantinga, that there is only one universe. Insistence on being fully actualized is little more than Thomistic dogmatism. Process theologians would definitely disagree on the grounds that only the primordial nature of God exists necessarily, but the contents of God’s consequent nature are contingent, created, changing, etc. This difficulty may be too complicated for the author to deal with in a short article, but it is worth considering nevertheless.

            5. Does the Big Bang have any relevance to the author’s concerns? Why or why not?

Author Response

Thanks for your fantastic feedback. I've edited my paper to reflect your comments. 

These include:

I've added a paragraph responding to the fallacy of composition. 

I've discussed the idea of the third way proving the current existing of the universe which is opposed to a Kalaam-type approach where Big Bang cosmology and the idea that creation can't be philosophically proven. 

I've gone into greater detail as to why the universe cannot be the necessary being in the same way that God is for Aquinas's metaphysics. 

Round 2

Reviewer 3 Report

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