More on the Status of Thomistic Common Natures

This is proving to be a fascinating topic.  Let's push on a bit further.

Aquinas says that any given nature can be considered in three ways: in respect of the esse it has in concrete singulars; in respect of the esse it has in minds; absolutely, in the abstract, without reference to either mode of esse.  The two modes are esse naturale (esse reale) and esse intentionale.  We can speak of these in English as real existence and intentional existence. 

According to Schopenhauer, the medievals employed but three examples: Socrates, Plato, and an ass.  Who am I to deviate from a tradition at once so hoary and noble?  So take Socrates.  Socrates is human.  The nature humanity exists really in him, and in Plato, but not in the ass.  The same nature exists intentionally in a mind that thinks about or knows Socrates.  For Aquinas, there are no epistemic deputies standing between mind and thing: thought reaches right up to and grasps the thing itself.   There is an isomorphism between knowing mind and thing known.  The ground of this isomorphism is the natura absoluta, the nature considered absolutely.  Call it the common nature (CN).  It is so-called because it is common to both the knower and the known, informing both, albeit in different ways.  It is also common to all the  singulars of the same nature and all the thoughts directed to the same sort of thing.  So caninity is common to all doggy thoughts, to all dogs, besides linking the doggy thoughts to the dogs.

My concern over the last few days has been the exact ontological status of the CN. 

This morning, with the help of Anthony Kenny, I realized that there are four possible views, not three as I stated earlier:

A. The CN really exists as a separate, self-subsistent item.

B. The CN exists only intentionally in the mind of one who abstracts it from concrete singulars and mental acts.

C. The CN has Meinongian Aussersein status: it has no mode of being whatsoever, and yet is is something, not nothing.  It actually has properties, but is property-incomplete (and therefore in violation of LEM) in that it is neither one nor many, neither universal nor particular, neither intentionally existent nor really existent.

D. The CN exists intentionally in the mind of God, the creator.

(A) is a nonstarter and is rejected by both me and Lukas Novak.  (B) appears to be Novak's view.  (C) is the interpretation I was tentatively suggesting.  My thesis was that the CN must have Aussersein status, but then it inherits -- to put it anachronistically -- all the problems of Meinongianism.  The doctor angelicus ends up with  Meinongian monkey on his back.

Let me now try to explain why I reject (B), Novak's view, and incline toward (C), given that (A) cannot possibly be what Aquinas had in mind. 

Consider a time t before there were any human animals and any finite minds, and ask yourself: did the nature humanity exist at t?  The answer has to be in the negative if there are only two modes of existence, real existence in concrete singulars and intentional existence in finite (creaturely) minds.  For at t there were no humans and no finite minds.  But surely it is true at t that man is rational, that humanity includes rationality.  This implies that humanity at t cannot be just nothing at all.  For if it were nothing at all at t, then 'Man is rational'' at t would lack a truth-maker.  Furthermore, we surely don't want to say that 'Man is rational' first becomes true when the first human being  exists.  In some sense, the common nature must be prior to its existential realization in concrete singulars and in minds.  The common nature cannot depend on these modes of realization.  Kenny quotes Aquinas (Aquinas on Being, Oxford 2002, p. 73):

Socrates is rational, because man is rational, and not vice versa; so that even if Socrates and Plato did not exist, rationality would still be a characteristic of human nature.

Socrates est rationalis, quia home est rationalis, et no e converso; unde dato quod Socrates et Plato non essent, adhuc humanae naturae rationalitas competeret. (Quodl. VIII, I, c, 108-110)

Aquinas' point could be put like this.  (i) At times and in possible worlds in which humans do not exist, it is nevertheless the case that rationality is included in humanity, and (ii)  the metaphysical ground of humans' being rational is the circumstance that rationality is included in humanity, and not vice versa.

Now this obviously implies that the CN humanity has some sort of status independent of real and intentional existence.  So we either go the Meioningian route or we say that CNs  exist in the mind of God.  Kenny:

Aquinas' solution is to invoke the divine mind.  There are really four, not three ways of considering natures: first, as they are in the mind of the creator; second, as they are in the abstract; theitrs, as they are in individuals; and finally, as they are in the human mind. (p. 74)

This may seem to solve the problem I raised.  CNs are not nothing because they are divine accusatives.  And they are not nothing in virtue of being ausserseiend. This solution avoids the three options of Platonism, subjectivism (according to which CNs exist only as products of abstraction), and Meinongianism.

The problem with the solution is that it smacks of deus ex machina: God is brought in to solve the problem similarly as Descartes had recourse to the divine veracity to solve the problem of the external world.  One ought to be forgiven for thinking that solutions to the problems of universals, predication, and intentionality ought to be possible without bringing God into the picture.  But this is a separate can of worms. 

Related articles

Metaphysical Grounding and the Euthyphro Dilemma

Lukáš Novák on Common Natures

Stanislav Sousedik's "Towards a Thomistic Theory of Predication"

Existentials and Their Equivalents: Aid and Comfort for the Thin Theory?

Aquinas Meets Frege: Analysis of an Argument from De Ente et Essentia

Gyula Klima on Thomistic Common Natures: Some Questions

Comments

[Elliott]

Bill,

Thanks for your follow-up post on common natures, and for the humor from Schopenhauer. I’m also glad that you have included option D in the discussion. D seems preferable for those inclined to Augustinian or Thomistic perspectives. I agree that one should avoid careless use of “deus ex machina”; its explanatory power is weakened with overuse. A good playwright, for example, should not employ this device to extricate himself from a self-inscribed corner. But it doesn’t follow that one should never use it. Ontology is not literary art (or science, which tries to avoid “deus ex machina” for similar reasons). Though I share your desire to understand universals, predication and intentionality, I would think that one sometimes reaches a point in philosophy where divine assistance might shed light on areas of mystery.

I see a rough analogy between the topic of Nagel’s recent book and the question of CN. As one digs into problems of consciousness, one faces the question: How can there be teleology, axiology, and rationality without God? Similarly, problems of CN lead one to questions about the divine mind. With regard to CN, I agree that options A and B fall short. Option C doesn’t seem feasible either. As you wrote, option C “inherits all of the problems of Meinong's doctrine of Aussersein”. CN might lack real or intentional existence, but it seems to have more than just Sosein. CN seems to have some sort of epistemic telos: it serves as the gatekeeper of the open channel between mind and thing, keeping the aptly named ‘deputies’ from interfering with mind-thing interaction. In short, CN serves a fundamental purpose in what Maritain and others have called the principle of intelligibility. And if CN serves a basic purpose in a principle that seems necessary for thought, how can it be understood as Aussersein? Perhaps there is an option E: some sort of abstract epistemic-telic realm of existence. But option D seems better: CN has esse intentionale in the mind of God.

[Gil Sanders]

I'm not convinced that this smacks of deus ex machina. It seems to me that we can simply say that its proximate ontological status is found in its real and intentional existence, but its ultimate ontological status is necessarily found in a necessary being, as is proper for all of contingent reality. The problem of a universal's ontological status only obtains precisely because of the nature of that universal and its concrete singular, wherein its essence is distinct from its existence. In other words, it is not necessary that such things be, but it is nevertheless possible that they be - thus explaining the difficulty that arises here. It is only proper then that it be grounded in the mind of God, which is by no means a deus ex machina. This is distinct from Descartes and his notion of divine veracity, since there is no notion of "proximate veracity" (as far as I know) and it just doesn't seem to be necessary to contingent objects that its veracity be known in some external manner; whereas the same cannot be the case for contingency as such.

[David Brightly]

Hello Bill,

Could we not say that a common nature such as humanity is a way (part of) the world might be, where we understand 'way' just as we do in 'Head, tail, tail, is one of the ways of placing three coins in a line'?

This could perhaps be seen as falling under the Meinongian option. But I'd be much happier defending 'there are eight such ways to arrange three coins' than 'there is a round square'.

[frequent reader]

I think comments like Elliot and David post point at what came to my mind about CN.

One of the moves that Whitehead made late in his development of process metaphysics was to insist that God exists. God was necessary to locate Platonic ‘eternal objects’, which seem like the CN being discussed here. Everything needs a reason, Whitehead vowed, and the only possible place for these universal forms – especially those not yet instantiated in reality – must needs God.

In working out a more ‘naturalized’ God, Hartshorne said these universals were not existent at all, but potentialities presented by outcomes of natural processes.

Professor V, if I got this right, how might it bear on the present discussion?

[Jan]

Dr Vallicella,

I wonder why your list of possible views on the mode of existence of CNs does not include:

A*. The CN really exists albeit not as a separate, self-subsistent item.

(A*) is a contradiction in terms for anyone who denies there are different modes of existence, but this is the position of neither you nor the Thomists. The best analogy for the mode of existence of the CN would be that of a second floor of a building. Second floors exist really and not intentionally --- ceilings, staircases, fire extinguishers and all. They are not however capable of separate existence. A second floor can only exist if there is also a first floor. Once it is considered as separate from the whole building, it becomes an abstraction.

Analogically, CN exists really and can be found in two kinds of entities: united with a mind (we call it intentional existence) or united with prime matter (we call it real existence). Note that I am not making a mistake of treating the CN as a basic metaphysical building block. Particulars and minds contemplating universal are basic objects, just as a three floor building is a more basic object than its second floor.

Now that I come to think about it, this view seems to create a vicious regress. Bob and Jack are both human because humanity is a real metaphysical constituent of both. But, on this view, there is no one Humanity over and above Bob and Jack. If there were, we would say that Jack's humanity and Bob's humanity are both reflections of the Humanity. What then allows us to recognise Bob's humanity and Jack's humanity as the same type of thing? Why, both must share a common metaphysical component called humanity* ! But there is no one Humanity* over and above etc.

A question to Lukas if he'd be willing to help: where does the unity (or commonality) of Bob's humanity and Jack's humanity come from?

[David McPike]

I don't see how this appeal to God is an ad hoc solution. It seems to follow naturally from the nature of the case (from the nature of God who is prior to all things, of intelligible things which *are* the things, and of intelligent creatures who are posterior to the things (in respect of their understanding)) that this should be the case. I don't understand how natures are supposed to differ "as they are in the abstract" and "as they are in the human mind" - other than in virtue of the fact that the latter should be taken to include various (including the other three) levels of abstraction; but how can they be disjunct categories, as Kenny seems to suggest?

[Elliott]

Common natures seem to be signs of a person/mind. Further, I’m not sure I see how there could be common natures without persons. Common natures serve an epistemic purpose and, it seems to me, come from ‘thinkers’ and ‘purposers’. Think about the following examples: the taxonomy of Linnaeus; the classification of film or literature according to genre; groups of people organized according to common factors (language, geographic location, ancestry, areas of interest or goal, occupation; tax bracket; etc); the classification of technology according to purpose; the classification of forms of communication according to common features; the ordering of astronomical bodies according to type; the ordering of numbers according to place value. Thinking about common natures is something a person does, and common natures just don’t seem possible without persons to think of them. If this is true, then options 1 and 3 don’t seem right. Option 2 doesn’t seem right either. Ultimately, common natures seem to be more than what I project via abstraction onto reality.

Imagine a possible world w that has no actual contingent beings and no finite minds. In w, ‘humanity’ is still a meaningful term; it serves as the common nature which would correspond to human beings, should such exist. If common natures require a person, and the common nature ‘humanity’ is in w, and no actual contingent beings or finite minds are in w, then what explains the common nature ‘humanity’ in w? Is it something that I, or some other finite mind, project onto w by abstraction? But if I think it through, the common nature does not seem to be only my abstract projection. The common nature ‘humanity’ seems to hold in w without my mental effort, or that of any other contingent, finite person. It seems that the only option left would be the divine mind. Common natures would then have esse intentionale in the divine mind.

Some might say that a world void of contingent things is impossible. Or some might say that the common nature ‘humanity’ in w serves no purpose, or at best serves only a potential purpose. But consider the centaur: there is a common nature for centaurs. Our world has no actual centaurs, but the common nature ‘centaur-hood’ holds meaning in our world. It enables us to think clearly about what centaurs are like, even though they lack actual existence. When I read the Chronicles of Narnia with my young sons, each of us understands, without difficulty, the nature of a centaur even though centaurs don’t actually exist. Even if there were no finite minds in this world, ‘centaur-hood’ would be a meaningful term. Wouldn’t the same hold for ‘humanity’ in w?

[Bill Vallicella]

Jan asks, >>I wonder why your list of possible views on the mode of existence of CNs does not include:

A*. The CN really exists albeit not as a separate, self-subsistent item.<<

Yes, like the Thomists, I hold that there are modes of existence. So I have no quarrel with them on that score.

Your analogy is interesting. I agree that the 2nd floor of a house, qua 2nd floor, i.e., under that exact description, cannot exist without a 1st floor. But surely it could exist by itself. Imagine a modular house built by stacking one rectangular box on top of another. Each could exist without the other and each could be either first floor or second floor.

A better way to make your point would be by asking me why I didn't consider the possibility that a CN is an accident. An accident cannot exist except in a substance, and no accident can be detached from the substance of which it is an accident. Accidents really exist without independently existing.

But the notion that CNs are accidents does make much sense. So I didn't list it.

[De Haan]

The importance of how one arrives at this doctrine, I believe, is being overlooked, and that can cause problems.

The approach by which Aquinas (and Avicenna) arrive at the doctrine of the CN are very important. For Aquinas every composite being or thing has at least two ontological principles: esse and essentia. But like the discovery of form and matter in natural philosophy these two principles are slowly reached through a process of analysis. They are vaguely given in any composite being, yet their distinction and complementary relation is not obvious.

When an object of consideration is placed before the mind's eye, there is a strong temptation to treat it like a thing or being and to thereby reify what is not necessarily a complete entity on its own. We treat surfaces of substances as though they were substances themselves inasmuch as they are subjects of color. In the case of the CN absolutely considered this is especially difficult to avoid, but the temptation must be avoided if the doctrine is to be understood. The metaphysical analysis of any being brings Avicenna and Aquinas to acknowledge that in every being its essence or CN is not its existence and its existence is not its CN. Further, these are two distinct ontological contributions to any complete ontological unit, that is, any being or thing. Part of the evidence given for this is the diverse kinds of existential actuality that a CN can receive. A CN can exist naturally or intentionally. But an "act of existing intentionally" and an "act of existing naturally" are no more complete things than the CN absolutely considered in itself. It is a mistake to treat either alone as having properties that only belong to complete beings and not their principles. Further, we do not ever discover these two ontological principles independently from the natural things or cognitive operations which provided the initial evidence for our distinction between these principles of every composite being. The reasoning leads us to hold that there is a CN which does not exist of itself or have any unity of itself, but is a distinct ontological principle in any composite being from its act of existence. The two principles together constitute composite beings which are either natural or intentional beings, that are either one or many, particular or universal. CNs in themselves are existentially and quantificationally neutral; the latter are only characteristics of complete beings which have an act of existence which actualizes its CN.

So, it is right to reject A, B, and C. Though the CN is not entirely unlike C.

Calling a common nature in itself a "thing" or a "something' an "entity" a "hoc aliquid" etc., is imprecise because the only way we came to recognize the common nature was by taking note of a common principle in all composite things (its essence, quiddity, or CN). We never simply encounter CNs because in themselves, CNs do not exist; that is the point of the doctrine. Asking in what way they exist confuses matters and undermines the purpose of the doctrine which is to try to intelligently talk about that common principle in all things that is not their existence, but in cooperation with an act of existence makes a composite being to be an actually existing thing of such a nature.

Historically speaking, Avicenna and Aquinas were not unaware of the LEM type objection. In fact, Avicenna takes it up at length. For Avicenna a CN like horseness, when considered in itself it is neither existing in reality nor in the mind, neither in potency nor act, not as a universal or particular, one or many, rather considered in itself it is just horsensess. He writes:

"If we are asked about horseness in connection with the two terms of what is contradictory (for example, "Is horseness A, or is it not A?") the answer would only be negation for whatever thing there is - not however that the negation comes after "inasmuch as" but rather before "inasmuch as." In other words, it must not be said, "Horseness inasmuch as it is horseness is not A," but "inasmuch as it is horseness, it is neither A nor anything else." (Avicenna, Metaphysics of the Healing, trans. Marmura, 2005), bk. V. ch.1, 5 [197]. He goes on at some length on this point.

I think Joseph Owens was correct that the Thomistic account of the CN in itself is a view that takes a lot of "therapy" to properly understand and then evaluate.

Finally, and I apologize for going on for so long, the Thomistic doctrine does "ultimately" turn to the Divine Ideas, but this is not a deux ex machina maneuver. But we should distinguish the problem of universals, which for Aquinas and Avicenna is resolved by the above distinctions, from the aitiological question of where do CNs ultimate come from. Resolves the one does not necessarily answer the other, and I think Kenny has confused matters by not keeping the two questions distinct. Avicenna treats the problem of universals in nine chapters in book V of his metaphysics and God is not ever brought in to resolve any of the problems here. His treatment of God's creation of natures is not taken up until books VIII and IX after he has provided arguments for God's existence.

For Aquinas, the divine ideas are brought in to answer the second question, not the first.