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The Aristotelian Proof Revisited: A Reflection

Published online by Cambridge University Press:  26 January 2024

Tyler McNabb*
Affiliation:
Franciscan Studies, Theology, and Applied Ethics, Saint Francis University, Loretto, PA, USA
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Abstract

McNabb and DeVito have recently argued that Graham Oppy’s objections to the First Way are found wanting. In response, McNabb and DeVito restructured the First Way on behalf of St Thomas. More recently, Joseph Schmid and Daniel Linford argue that the restructured argument given by McNabb and DeVito is problematic, claiming that it is either valid but unmotivated or it is plainly invalid. In this paper, I argue that McNabb and DeVito’s schematic glossing of the First Way is both valid and motivated.

Type
Article
Copyright
© The Author(s) 2024. Published by Cambridge University Press on behalf of Provincial Council of the English Province of the Order of Preachers.

In Graham Oppy’s Arguing about Gods, Oppy argues that the Aristotelian proof is clearly invalid.Footnote 1 The formulation he gives goes as follows:

  1. (1) Some things are in a process of change.

  2. (2) Whatever is in a process of change is being changed by something else.

  3. (3) An infinite regress of changers, each changed by another, is impossible.

  4. (4) (Hence) There is a first cause of change, not itself in a process of change.Footnote 2

McNabb and DeVito originally took Oppy’s validity concern to be in reference to St Thomas’ conclusion that there is an unmoved mover who is, Himself, wholly unmoved.Footnote 3 However, it appears to me that Oppy’s original concern was that St Thomas concluded that there is simply only one unmoved mover. His worry does not relate to the mover’s immutable status; rather it relates to the number of movers established by the premises (i.e., if there is simply one unique mover). A direct response to this concern comes later in the paper. Nonetheless, it is not clear what work of St Thomas Oppy has in mind when he puts St Thomas’ argument in schematic form. This is how St Thomas summarizes the argument in the Summa Theologica:

The first and more manifest way is the argument from motion. It is certain, and evident to our senses, that in the world some things are in motion. Now whatever is in motion is put in motion by another, for nothing can be in motion except it is in potentiality to that towards which it is in motion; whereas a thing moves inasmuch as it is in act. For motion is nothing else than the reduction of something from potentiality to actuality. But nothing can be reduced from potentiality to actuality, except by something in a state of actuality…Therefore, whatever is in motion must be put in motion by another. If that by which it is put in motion be itself put in motion, then this also must needs be put in motion by another, and that by another again. But this cannot go on to infinity, because then there would be no first mover, and, consequently, no other mover; seeing that subsequent movers move only inasmuch as they are put in motion by the first mover; as the staff moves only because it is put in motion by the hand. Therefore it is necessary to arrive at a first mover, put in motion by no other; and this everyone understands to be God.Footnote 4

As McNabb and DeVito have pointed out,Footnote 5 the assumption that the first cause is unchanged is implicit. Since ‘whatever is in motion must be put in motion by another’, and because postulating an infinite number of instrumental causes does not help us in making sense of hierarchical causation, we are simply left with there needing to be a first cause that is itself unchanged. Moreover, if one reads St Thomas’ earlier work in the Summa Contra Gentiles, one will see that St Thomas’ reasoning is even more explicit:

Of these ways the first is as follows. Everything that is moved is moved by another. That some things are in motion—for example, the sun—is evident from sense. Therefore, it is moved by something else that moves it. This mover is itself either moved or not moved. If it is not, we have reached our conclusion—namely, that we must posit some unmoved mover. This we call God. If it is moved, it is moved by another mover. We must, consequently, either proceed to infinity, or we must arrive at some unmoved mover. Now, it is not possible to proceed to infinity. Hence, we must posit some prime unmoved mover.Footnote 6

Note the relevant exclusive disjunctive statement: This mover is itself either moved or not moved. Again, since postulating an infinite number of instrumental movers could not ground motion, at least by itself, we are left with St Thomas’ conclusion that we must arrive at an unmoved mover. McNabb and DeVito then move on to state that a more faithful glossing of St Thomas’ argument would look like what follows:

  1. (1) Some things are in a process of change.

  2. (2) Whatever is in a process of change is being changed by something else.

  3. (3) What moves something else is either moved or not moved.

  4. (4) An infinite regress of changers, each changed by another, is impossible.

  5. (5) (Hence) There is a first cause of change, not itself in a process of change.Footnote 7

1. Schmid and Linford on validity

Recently, Joseph Schmid and Daniel Linford have responded to this formulation, arguing that the syllogism is only valid if we interpret (4) in a way that (a) interprets the conclusion as saying

there is at least one first cause of at least some changes, not itself in a process of change; and (b) Premise (4) is interpreted as denying the possibility of the following conjunction: (b.i) every first member in every per se chain of change is itself changed in a manner unrelated to the causal power of the series for which that first member serves as terminus, and (b.ii) every first member in every per accidens chain of change is changed in some manner, whether in a per se or per accidens series.Footnote 8

Of course, what Schmid and Linford proceed to do is argue that a denial of (b.i) and (b.ii) is unmotivated. There is nothing that McNabb and DeVito offer that demonstrates that the first member of a per se causal chain must be unchanged in every respect.Footnote 9 Perhaps, we could imagine that a first member of a per se causal chain is moved not in respect to the relevant power it gives to others but in other non-relevant respects. Schmid and Linford give an example of a water-pot-stove-fire causal chain. The fire acts as the first member. That is, the water boiling in the heated pot is ultimately grounded in the fire itself. Nonetheless, the fire is not wholly unmoved. It too has potentialities (potentialities not relevant for the relevant causal chain) and requires external forces to move on these potentialities for it to exist.Footnote 10 What we arrive at then is simply that there is ‘some entity E that is not (presently) moved in respect of the causal power or property of the series for which E serves as terminus’.Footnote 11 But this, of course, does not mean that the first member itself does not have potentiality. As Schmid and Linford put it, ‘This conclusion only delivers a world populated by disparate, mundane unmoved movers, e.g., fire, minds, etc., each of which has the built-in power to cause changes in their respective series of changes. Classical theism is very far off indeed’.Footnote 12 This, I take it, is closer to Oppy’s original point.

To their credit, Schmid and Linford are open to the possibility that the Thomist might try to argue that a unique first member of a causal chain must be purely actual. They go on to explore this possibility, calling this reply, the Path Forward.Footnote 13

One approach that Schmid and Linford entertain comes from Edward Feser. Feser endorses the principle agere sequitur esse (action follows being). According to Schmid and Linford, Feser cashes out the principle as follows: Since S exists F-wise, F will then act F-wise.Footnote 14 Schmid and Linford then understand Feser to argue that if T existed in a changeable manner, then T would act in a changeable way. But if one of T’s actions is unchangeable, then so is T.Footnote 15 Since the first member of the causal chain has at least one action that is uncaused or unchanged, T must then be unchangeable, full stop.Footnote 16

Schmid and Linford go on to argue that endorsing Feser’s glossing or application of agere sequitur esse won’t help the Thomist. To argue that there is one unchangeable act from T, however, is to beg the question. Moreover, Schmid and Linford go on to formulate attempted counterexamples to agere sequitur esse, or at least, Feser’s version.

So, it seems that if the Thomist is to interpret (4) in a way that denies (b.i) and (b.ii), something more needs to be offered. Why think that there is at least one first or primary cause in a per se order causal chain that is wholly uncaused in all respects? While Schmid and Linford’s response to McNabb and DeVito’s work is stimulating and interesting, I think they overlook an important assumption that Thomists typically have when understanding the nature of primary causes of per se causal chains. Let’s return to Schmid and Linford’s water-pot-stove-fire example. Schmid and Linford are right in that we can consider the fire to be the primary mover in this per se ordered causal chain. And once again, Schmid and Linford are right in thinking that the primary mover in this instance wouldn’t need to be wholly unmoved, as it too would have various potentialities. Nonetheless, the fire has the power to burn in virtue of the fire’s essence. The primary mover has its power in virtue of what it is. But what actualizes the fire’s essence to exist? The Aristotelian-Thomist would argue that something that is already in act would need to move upon the fire’s potential to exist. Now, maybe Schmid and Linford would argue that that which is in act can possess non-relevant potentiality (non-relevant to its causal power). Why must there be a primary mover behind the fire that is pure act and not some act-potency compound?

Recall that the primary cause of a per se causal chain has its power in virtue of what it is. So, the primary actualizer of the fire’s essence then is able to actualize the essence’s potential to exist just in virtue of what it is, namely pure existence or the pure act of existence. Pure actuality then is the actualizer’s nature and thus identity.

Perhaps you are still not convinced that the primary cause of the fire’s essence must be a pure act and not some act-potency compound. Maybe you think existence could be caused in some way not relevant to its causal power to make essences exist. As Gaven Kerr points out, ‘in what respect could a first cause of esse [existence] be caused? If the first cause of esse is successfully established, then it is the cause of everything other than itself that has esse. To suggest that such a first cause of esse could be caused in some respect would be to suggest that it is caused by what it itself causes…’.Footnote 17 In this case, we now have reason to reject (b.i).

2. A possible response

Perhaps, Schmid and Linford would concede that the ‘Path Forward’ I have sketched above does not suffer from the same issues they raise with Feser’s approach. However, so they might argue, I have left my De Ente styled defense of the First Way susceptible to the criticisms they raise against the De Ente Proof.Footnote 18 Maybe the criticisms they give elsewhere to the De Ente Proof will also apply to my response here.

It is not obvious that this is the case. My De Ente inspired defense of the First Way merely assumes that a first member of a per se causal chain has its causal power in virtue of what it is. I simply applied this thesis to the primary cause of an essence’s existence. I have not, for example, defended or assumed all of the premises of the De Ente Proof (see, e.g., the reconstructed argument mentioned below). Nonetheless, in case I am wrong, let’s engage Schmid and Linford’s general response to the De Ente Proof and then specifically address what they take to be Kerr’s reconstruction of the argument.

Following a general worry that Alexander Pruss has elsewhere raised,Footnote 19 Schmid and Linford argue that there is an infinite regress objection that can be raised against the De Ente proponent. Supposedly, De Ente proponent will assume that Socrates’ existence needs to be grounded in an act of existence. That is, Socrates’ existence needs a truth-maker for its existence. But if this is the case, then does Socrates’ act of existence also have an act of existence, and so on ad infinitum?

It is important to note here that the Thomist can claim that it is only substances that exist (i.e., enjoy an act of existence).Footnote 20 The substance’s parts do not have an act of existence. Thus, the act of existence does not itself need an act of existence, so on infinitum. Perhaps certain versions of Thomism or Classical Theism are committed to this, but not the one this paper advances.

As for their criticisms of the De Ente Proof, Schmid and Linford particularly attack the first three premises from the following syllogism:

  1. 1. Prior to an essence-existence composite’s having existence, the essence-existence composite is nothing.

  2. 2. If (1), then essence-existence composites do not have existence in virtue of what they are.

  3. 3. If essence-existence composites do not have existence in virtue of what they are, then essence-existence composites have existence from something ad extra.

  4. 4. If essence-existence composites have existence from something ad extra, then essence-existence composites are nothing unless they participate in a cause of their existence.

  5. 5. If essence-existence composites are nothing unless they participate in a cause of their existence, then in order to continually exist, essence-existence composites must continually participate in a cause of their existence.

  6. 6. If, in order to continually exist, something must continually participate in a cause of its existence, then that thing does not inertially persist.

  7. 7. Hence, no essence-existence composite inertially persists. (1–6)

Addressing premises (1) and (2), Schmid and Linford state the following:

One difficulty that arises with premises (1) and (2) is that prior to anything’s existing, that thing is nothing. For if x were something prior to its existence, then x’s existence would be prior to its existence, which is absurd. There is thus nothing special about essence-existence composites here—even prior to the existence of something in which essence and existence are identical, that thing is nothing. In that case, though, premise (2) would entail the conclusion that nothing exists in virtue of what that thing is. For if (as premise (2) says) not existing in virtue of what x is follows upon the fact that prior to x’s existence, x is nothing, then—since the latter is true of everything—one can infer that nothing exists in virtue of what that thing is. But this, of course, is incompatible with the very De Ente argument Kerr is proffering, since such an argument concludes that there is something that does exist in virtue of what that thing is and that imparts existence to everything else that doesn’t exist in virtue of what those other things are.Footnote 21

I take it, the idea is that if we accept (1) and (2), we will be committed to the view that prior to a thing existing, it is nothing. This applies to everything, including that which, by its very nature, exists as there is nothing special about the nature of composites. If there is nothing before the non-composite, then the non-composite does not exist either.

There are two quick replies one can make. First, one might follow the so-called ‘Blackfriar’ tradition and deny that God is a thing.Footnote 22 In this way, even if some metaphysical principle is true of everything, it might not be true of God since ‘He is no thing’.Footnote 23 More to the point, however, the inference from composites to that which exists by its very nature can’t be made. For you can’t speak of ‘before’ when it comes to pure existence itself. Talking about what is before only makes sense when we are discussing composites.

Finally, Schmid and Linford argue that the neo-classical conception of God is a counterexample of (3):

In such a case, the essence-existence composite in question would not have existence in virtue of or from anything. Suppose that neo—classical theism is true. The neo-classical God’s essence, we can suppose, is not numerically identical to the neo-classical God’s existence. The neo-classical God, then, is an essence-existence composite. Nevertheless, the neo-classical God is the necessarily existent, unlimited, perfect, ultimate foundation of everything else. The neo-classical God therefore doesn’t exist in virtue of anything. Instead, the neo-classical God is uniquely unexplained.Footnote 24

Hence, according to Schmid and Linford, it is not true that all ‘essence-existence composites have existence from something ad extra’. The Thomist, of course, will likely think that the neo-classical conception of God is not only not possible but also a contradiction in terms. The Thomist is going to assume a constituent ontology and, as a result, argue that the neo-classical theist God will depend on His parts for His existence. This, of course, will conflict with God’s aseity. God can’t be both a se and depend upon His parts for His existence. Then the neo-classical conception of God won’t be seen as a convincing counterexample to (3). Now, you might argue that the Thomist has the duty to defend a constituent ontology and defend the argument from aseity. But note the context of McNabb and DeVito’s paper. McNabb and DeVito’s thesis is not that the First Way is sound, only that Oppy has not done away with the Aristotelian proof. It is enough to simply show that Oppy needs to do more work than he has already done. As of now, given the Thomist’s commitments, it does not appear that Oppy has done away with the proof.

3. Existential inertia

Schmid and Linford move on from critiquing the formality of the argument to also critiquing McNabb and DeVito’s response to Oppy’s endorsement of what we can call existential inertia (EI). EI is the thesis that substance S can continue to persist without a concurrent sustaining cause. Elsewhere, Oppy invites his readers to imagine a red chair.Footnote 25 The chair will stay red unless something outside of it changes the color. For example, the chair will stay red unless I knock over blue paint that splatters on the chair.

In response to Oppy, McNabb and DeVito, inspired by Feser, argue that the chair will not remain red unless it has the relevant microchemical properties situated in the right way.Footnote 26 That is, there is something that needs to continually be in place in order for the chair to remain red. And of course, those microchemical properties have the potential to be arranged in the right way, but what moves upon that potential? The need for a primary cause in this causal chain is evident. And as McNabb and DeVito have stated previously, even if objects have the ability to persist without a concurrent sustaining cause, there is a question about what moves on the potential of such objects to have the sort of natures that they have, such that they are able to persist without such a cause.Footnote 27 It seems modally implausible that they do so necessarily. If objects have the potential to exist in this way, the question remains what moved on such potential?

Now, Schmid and Linford are not convinced. After moving the discussion from how the chair will remain red to simply how the chair will exist, Schmid and Linford first take issue with appealing to microstructures to deduce that there is an unmoved mover:

The problem is that appealing to microstructure as a ‘cause’ upon which a chair depends simply undermines persistence arguments’ inference to an unsustained sustainer of the existence of everything apart from itself. For the microstructure of the chair is a component of the chair, and only ‘actualizes’ the chair in the sense that something ‘depends’ (in some sense) on its components. But upon tracing this causal chain of ‘dependence’ down to a first member, all we’re entitled to infer about the first member is that it is an uncomposed component, not that it is an unactualized actualizer of the very being or existence of the secondary members of the dependence chain in question.Footnote 28

Second, Schmid and Linford argue that McNabb and DeVito have confused the material cause of a chair with the efficient cause.Footnote 29 The structure of the chair is what the chair is made up of. It is not what causes the chair to be. Finally, Schmid and Linford argue that McNabb and DeVito have explicitly rejected an Aristotelian top-down approach to part-whole relationships.Footnote 30 This seems ironic given that the argument we defend is grounded in Aristotelian thought.

I will now respond to each charge in turn. By uncomposed components, I take it that Schmid and Linford have in mind something like quarks. What McNabb and DeVito have shown then is that eventually we will need to bottom out in fundamental parts or quarks that make up the chair. Further building blocks are simply not required. McNabb and DeVito have not established more than this, or so they say. Let’s concede that McNabb and DeVito have only established that behind the chair there are fundamental particles. Nonetheless, quarks have potential to exist in certain ways and to build substances by being in relations with other quarks, and so on. Having potentiality, quarks are composites. Quarks then stand in relation to potency. What moves on the potential of these quarks to be in the way that they are? Again, we need to appeal to something outside of the fundamental components.

Regarding Schmid and Linford’s second point, it is important to clarify that McNabb and DeVito’s response was originally in reference to a chair remaining red, not existence simpliciter. On some views of color, color emerges from complex microchemical properties being in place. McNabb and DeVito were arguing that, on a plausible construal of color, the microchemical properties need to be in place if the red in the chair is to continue to exist. There is no confusion between the material cause and the efficient cause here.

Now, can McNabb and DeVito’s response be applied to the existence of the chair simpliciter? For argument’s sake, let’s say that parts are more fundamental than the whole. If I endorsed a bottom-up view, I could think wholes emerge from their parts. In this case, the chair emerges from the more fundamental microchemical structure of the legs and the seat of the chair, just like the color of the chair emerges from complex chemical properties. Or if we wanted to speak about metaphysical parts, we could say that the chair emerges from the bundle of tropes that compartmentalize together.Footnote 31 Now, I grant that this approach is at odds with Aristotelian top-down approaches to part-whole relations. However, we can assume that an emergent part-whole theory could serve McNabb and DeVito well for dialectical purposes when the context of the debate is whether or not God exists. At least, if as some naturalists assume, bottom-up views fit well with naturalism.

4. Top Down

Nonetheless, McNabb and DeVito do not need to accept a bottom-up theory. You can run a similar move with top-down models. I could argue more broadly that in order for the chair to remain a chair, it needs to continually be formed in such a way that the chair remains what it is. The idea is that the chair depends on its form and the form depends on something else. We have the same issue as we have with the bottom-up approach. We need a primary cause. Now, engaging with these issues at length is clearly beyond the scope of this paper. My aim here is to simply to provide context for McNabb and DeVito’s appeal to bottom-up accounts and resolve the tension between what McNabb and DeVito say in their paper with Aristotelian philosophy more generally.

5. Summary

In summary, Schmid and Linford gave an ingenious and interesting reply. However, I have argued that their reply falls short of being successful. I argued that the way McNabb and DeVito gloss St Thomas’ argument is indeed valid. Of course, I concede that one needs to interpret (4) as ruling out the possibility of (b.i). Nonetheless, I argued that there is motivation to reject (b.i). Moreover, I argued that Schmid and Linford’s recent criticisms of McNabb and DeVito over EI can be found wanting.

References

1 Graham Oppy, Arguing about Gods (NY: Cambridge University Press, 2006), p. 103.

2 Ibid.

3 Summa Theogica, 1.2.3, trl. Fathers of the English Dominican Province.

4 Summa Contra Gentiles, 1. 13.3, trl. Pegis.

5 Tyler McNabb and Michael DeVito, ‘Has Oppy Done Away with the Aristotelian Proof?’, Heythrop Journal, 61:5 (2020), 7–8. <https://doi.org/10.1111/heyj.13604>.

6 Quoted above, footnote 4.

7 McNabb and DeVito, ‘Has Oppy Done Away with the Aristotelian Proof?’, 2–3.

8 Joseph Schmid and Daniel Linford, Existential Inertia and Classical Theistic Proofs (New York: Springer, 2022), p. 19.

9 Ibid., p. 22.

10 Ibid.

11 Ibid.

12 Ibid., p. 28.

13 Ibid., p. 29.

14 Ibid., p. 21.

15 Ibid.

16 Ibid.

17 Gaven Kerr, Aquinas’s Way to God: The Proof in De Ente et Essentia (Oxford: Oxford University Press, 2015), p. 147.

18 See chapter 7 of Schmid and Linford, Existential Inertia and Classical Theistic Proofs.

19 See Alexander Pruss, The Principle of Sufficient Reason: A Reassessment (New York: Cambridge University Press, 2009–2010).

20 Thanks to Gaven Kerr for making this point to me.

21 Schmid and Linford, Existential Inertia and Classical Theistic Proofs, p. 247.

22 See, for example, Tyler Dalton McNabb and Erik Baldwin, Classical Theism and Buddhism: Connecting Metaphysical and Ethical Systems (London: Bloomsbury, 2022).

23 Psudeo-Dionysius: The Complete Works, trans. by Colm Luibheid (Mahwah: Paulist Press, 1987).

24 Schmid and Linford, Existential Inertia and Classical Theistic Proofs, p. 249.

25 Graham Oppy, ‘On Stage One of Feser’s Aristotelian Proof’, Religious Studies, 57:3 (2021), pp. 491–502. <https://doi.org/10.1017/S0034412519000568>.

26 McNabb and DeVito, ‘Has Oppy Done Away with the Aristotelian Proof?’, 7–8.

27 Ibid.

28 Schmid and Linford, Existential Inertia and Classical Theistic Proofs, pp. 211–12.

29 Ibid.

30 Ibid.

31 Keith Campbell, ‘The Metaphysic of Abstract Particulars’, Midwest Studies in Philosophy, 6 (1981), 477–88.