Slow walk through the Fourth Way

1.) Among things, some are more and less good, true, noble, etc.

Invenitur enim in rebus aliquid magis et minus bonum, et verum, et nobile, et sic de aliis huiusmodi.

2.) But more and less are attributed to different things when they approach, in different ways, something which is maximal, just as a hot thing more or less approaches what is maximally hot.

Sed magis et minus dicuntur de diversis secundum quod appropinquant diversimode ad aliquid quod maxime est, sicut magis calidum est, quod magis appropinquat maxime calido.

Leibniz makes this premise the main difference between what is more and less in extension or multitude and what is more and less in perfection. In the first sense more and less is measured by the parts of the things compared whereas in the second sense it is measured by the whole nature of the things compared. So five is greater than two in virtue of having three more parts while one man is greater than another in virtue of being a more perfect instance of the nature shared by both. The common nature shared is the limit and maximum that allows us to reckon one person greater than another.

Thomas’s heat example is taken from a theory about heat that saw fire as a sort of chemical substance that mixed with things to make them hot in exactly the same way that alcohol mixes with things to make them intoxicating. Just as things are more and less intoxicating relative to pure alcohol (which is exactly how we list their ABV) so too things were more or less hot relative to pure fire (which we usually just call “fire”).

3.) So there is something maximally true, best, and maximally noble and, as a consequence, there is a maximal being, for things which are maximally true are most of all beings, as is said in II Metaphysics.

Est igitur aliquid quod est verissimum, et optimum, et nobilissimum, et per consequens maxime ens, nam quae sunt maxime vera, sunt maxime entia, ut dicitur II Metaphys.

A conclusion from above

4.) But what is maximal in any genus is the cause of all other things in that genus, as fire, which is maximally hot, is the cause of all hot things. Therefore there is something which is a cause of existence, goodness and of any perfection in all things, and this we call God.

Quod autem dicitur maxime tale in aliquo genere, est causa omnium quae sunt illius generis, sicut ignis, qui est maxime calidus, est causa omnium calidorum, ut in eodem libro dicitur. Ergo est aliquid quod omnibus entibus est causa esse, et bonitatis, et cuiuslibet perfectionis, et hoc dicimus Deum.

The fire example is explained in (2), and Thomas here makes it explicit.

The Fourth Way thus proves not that the greater or lesser perfections require some separate subject of maximal properties, but that the very goodness in things is a manifestation of goodness itself. As an analogy, when you say this drink is 85% alcohol and therefore more intoxicating than the drink with 15% alcohol, you’re not comparing it to a maximum in the sense that you compare them both to some third drink that is pure alcohol – what you mean rather is that the 85% drink itself exists as a more complete instance of pure alcohol. That is, you’re talking about something in things in a more and less complete way, though understood not qua material cause but qua more and less perfect realizations. There is a sense in which the Fourth Way describes things as more and less good by the amount of God they have in them, though this “amount” can’t be understood in the line of as a material cause but as a realization of some ideal. To understand God as a material component had more or less in things would simply repeat the mistake of confusing the more and less of quantity with the more and less of perfection, but once one clarifies the sort of amount he’s talking about, a thing is more or less true, good and noble by the amount of God of it contains or fails to contain.

It follows from this that natures, so far as they are standards of what is good, true, noble, or in any way perfect are nothing more than the mixed and variegated modes in which divinity can be manifested.

Fourth Way

What is greater or less in the genus of quantity is not more perfect since it arises from the matter. What is greater or lesser in virtual quantity arises from form and therefore always has a paradigm, i.e. maximal perfection. For virtual quantity in a genus (i.e. quality) this form is a paradigm within nature or imagination, and like all things in nature (or a genus) it need not exist. For virtual quantities transcending a genus the paradigm is outside of nature and therefore exists necessarily.

The Fourth Way

The first axiom in Leibniz’s DM is

[T]hose forms or natures which are not susceptible of [perfection] to the highest degree, say the nature of numbers or of figures, do not permit of perfection.

Said another way, what is greater or lesser so as not have a greatest is not greater by being more perfect.

Contrapositively, we get the first premise of the Fourth Way, that whenever something is more or less great by being more perfect, there is something most perfect.  Leibniz doesn’t bother to point out that some things are, in fact, more or less perfect than others though STA does, but given this there exists some maximally perfect being.

The Fourth Way, fire, and entropy

The Fourth Way makes the claim that because things are more or less hot there is something maximally hot. This was based on STA’s idea that fire was a chemical released by burning, meaning that a campfire took fire out of logs just like a still takes alcohol out of fermented things. His example was incorrect but the principle remains as a valuable though unarticulated postulate for chemists, which is assumed in their long list of separation processes. If we wanted to update the fire example we could do so with any property of pure substances: e.g. given that some drinks are more and less intoxicating, there is something maximally intoxicating.

Digging deeper in the Fourth Way one finds STA’s reliance on the idea that every act communicates itself so far as possible. “Communicates” is a transliteration, not a translation – what he means by the term is the complementary description to participation. Participation is the dependence of a part on something that it common, the way players participate on teams or interlocutors participate in discussions. This generalizes to the fact that matter participates in form, and then further generalizes to potency participating in act. The reverse activity from act to potency is what STA calls communicatio, though there is no corresponding technical term in English.*

So why STA was wrong about fire being a chemical existing in either a pure or mixed state, he was right that heat is an act of some potency, and that this act communicates itself or diffuses itself as far as possible. The communicatio of heat is familiar from the phenomena that we label entropy, though we give an accidental description of it as a tendency to disorder. Nothing about the phenomena changes if you view nature as diffusive self-giving or dissipating tendency to disorder, but these are completely different views of what nature is and what it is up to. Our description is equivalent to describing a car as an exhaust-making tool, or breathing as a process that seeks to make carbon dioxide.

On the communicatio account of entropy the closest analogue to the Fourth Way, ironically enough, is Sean Carroll’s argument that the cascade of entropy is necessarily infinite. Reformulated in STA’s terms, this is nothing but an application of the principle that all finite diffusions or communications of act are participants in an infinite and unlimited act. I’d agree with Carroll, of course, and he might even have a whole shelf full of models that point to the need for some time with infinite energy, but I’m pretty sure that if we took the idea seriously then, just like Aristotle did in Physics VIII, we’d find that there’s a limit to how much energy we could hope to find in any given physical system. So what if your theory demands more actuality than a physical system can provide? That’s a pretty good account of what a cosmological argument is.


*One synonym for communicatio is “diffusio” which is the term STA tends to apply to the communicatio of the good (cf. “the good is diffusive of itself”).

The source text of the Fourth Way

STA says twice in the Fourth Way that the argument is taken from Metaphysics II. The specific text is pretty clearly 993b 24. The Greek text is garbled, but STA smooths it out and gives a commentary that concludes to the existence of a separate form who is the cause of existence. For another translation, see here, paragraphs 292-5.

Whatever is called supreme among other things is so in virtue of something being caused in those others that is predicated of them univocally, in the way that fire is the cause of heat in the elements. And so since heat is said univocally of fire and the thing that is composed of elements, it follows that fire is the hottest thing.

[Aristotle] mentions univocation because sometimes an effect is not similar to its cause in a way that makes it of the same species, due to the excellence of the cause. The sun, for example, is a cause of heat in lower things, but the inferior things cannot receive the effects of the sun or of other celestial bodies so as to be one species with them, since they share in matter. Because of this we do not say that the sun is the hottest thing in the way fire is, but that the sun is something more than even what is hottest.

Truth, however, is not limited to a species but relates to all that is, and because the cause of truth is one with its effect in both name and logos, it follows that what is a cause to things derived from it, so far as they are true, is the supreme truth.

Aristotle later concludes that the principles of things that always exist, sc. the celestial bodies, are necessarily supremely true. He gives two reasons: (1) they are not “sometimes true and sometimes not” and because of this they transcend what is generable and corruptible in truth, that sometimes exist and sometimes do not. (2) Nothing is a cause of the celestial bodies else unless it is a cause of their being. And because if this something transcends even the celestial bodies both in being and truth, since even if these are incorruptible they nevertheless have a cause of being moved and even of their being, as the Philosopher explicitly says.

This has to be the case since it is necessary that all things that are composite or exist by taking part in something else reduce, as to their causes, to things which exist by definition (quae sunt per essentiam). All corporeal things are actual beings only so far as they exist by taking part in forms. So there must be some separate substance which exists by definition which is the source of corporeal substance.


Chain relatives and the Fourth Way

I’ve claimed that all the Five Ways begin with a type of chain relative, i.e. repeatable relations like “being to the left of” or “being fathered”. But what about the Fourth Way? STA seems to mention no chain relatives at all, but simply says right out of the gate that things that are more and less good, true, and dignified, etc. (GTDE) exist relative to something maximal. Nevertheless, we understand the claim better if we take it as a conclusion for a reductio ad absurdum that assumes the GTDE has no maximal but is only relatively greater and less.

Start here:

[The] bald assertion of a difference between fair and foul things, virtuous and vicious actions, offers no standard whereby to determine their difference no reason for the similarity of all fair things qua fair and for their difference from all that are foul. So long as these are only characteristics of material individuals no standard can be found, for to measure individuals against one another is to seccumb to relativism.

Harold Cherniss, The Philosophical Economy of the Theory of Ideas. 

Logically, things are either more or less GTDE only relative to each other or ultimately to something maximal. Said another way, iff we take the more and less GTDE as a chain relative where something less relates to something greater, with the greater in turn being something less relative to some greater, etc; then this either goes on without ever requiring some ultimate, or some ultimate is required. But if the first, then GTDE is arbitrary and consists in nothing more than the irrational prejudice. I stress that it is an irrational prejudice to set it apart from what we are doing when we declare something better by hypothesis, since the whole point in treating something as if it is greater in GTDE is to find out what is in fact greater, i.e. to discover some standard why things are more and less what they are. But to assume that all one ever has are chain relatives is to dogmatically rule out discovering anything that is truly better in fact, and so to deny any point of framing hypotheses about it. But it is reasonable to form hypotheses about what is more or less GTDE, and so these things must exist relative to something maximal.

This throws light on an important difference between what is more and less in mathematical and virtual quantity. Mathematical quantities are given in greater or less on some continuum or set of ordered points, say, the number line. This number line fixes what is greater or less in terms of position or direction: what is to the right is greater than what is to the left. But in order to develop the analogue to position or direction in virtual quantities we need some standard S1 different from the things which we order. If S1 is itself variable in GTDE to S2, then unless S2 is given we cannot be sure even of the “direction” we have set up for the things falling under S1. The difference between the more and less in quantity and the GTDE is that what sets the direction of the greater an less in quantity is not itself a quantity, but what sets the order of, say, goods is itself a good. This is why the order of integers need not have a greatest but the order of virtual quantities must, and why, even though things greater and less in virtual quantity are chain relatives that can have an indefinite order of things merely relatively greater and lesser, it is impossible that all virtual quantities be of this kind.

Leibniz, the Fourth Way

Leibniz’s Discourse on Metaphysics opens with a proof logically equivalent to the Fourth Way:

Whatever is more and less with no greatest possible is not more and less perfect

So (by contraposition) whatever is more and less perfect is such relative to the greatest possible perfection.

His first claim is supported by an insight into numbers, which admit of no maximum and are not better or worse by being more or less. We can hit the same conclusion by considering privations: if a threshold has to be the same width as a 30” door, there is no maximal way it can fall short of being that size, since falling 30″ short would leave one with no threshold at all. And so if anything is better and worse, there must be some greatest possible perfection.

The Augustinian tradition established that the greatest possible perfection is God. In giving a critique of idolatry, Augustine pointed out that if one could think of something better than the object they were considering, then the object they were considering was not God. So by the same contrapositive move  Leibniz made, God is the object than which nothing greater can be thought.

Fourth Way, and its real difficulty

Here’s the Fourth Way in a sentence: there are things that can only be said perfectly and precisely of a being that all recognize as God. St. Thomas lists three or four: good, true, dignity and existing, but he gestures in the direction of many more.

Mistaken or imperfect notions are used analogously to the correct or perfect. Malaria said of “A disease caused by bad swamp air” and “fever caused by a pathogenic protozoa that invades red blood cells” is used like this, as is heat when said of (the supposed element) fire, phlogiston, and mean molecular motion or “dropped the Hiroshima bomb” when said of Truman and the Enola Gay.

Imperfect or imprecise notions need not be separable from some subject and can even belong to it essentially or necessarily. While we can have malaria without swamp air or swamp air without malaria, it does not follow that we can have fire without heat or a dropping of the Hiroshima bomb without the Enola Gay (or some plane like it). But we can still have to distinguish these sorts of essential or necessary things into a primary and secondary.

Though I’m speaking of analogous uses of terms and how things are known, they are shorthand to make a metaphysical point. True, the drift of the argument is this:

Mistaken and imprecise notions are said analogously to the true one.

All notions that are separable from some subject or secondary to it are imprecise.

But the point is not to talk about how something is known but about the reality that is being said of the thing, and when considered this way it is hard not to notice that existence is said separably of any natural substance. On a substance-ontology, where everything traces back to substance and neither the universe nor matter nor forms/laws in mathematical abstraction are substance, it’s clear that natural substances exist only derivatively from a supernatural deus. But the contemporary mind has a great deal of metaphysical confusion about things like universes, physical laws and conserved quantities which makes us less able to conclude to divinity. We recognize easily that natural substance depends on something everlasting, uniform, and even abstract-intelligible but we hesitate to call it “God”.  We run the same argument on the idea of “dignity” and think it should conclude to us.


Fleshing out the Fourth Way

The Fourth Way is a general argument that God is X to a maximal degree where X is “things like” (huiusmodi) good, true, dignity, being, etc. This means that God is most of all what we mean by these things, and even though we call other things good this is only because the first things we name are not the highest instances of what deserve that name. We can show this by looking at the great number of things that the Fourth Way is talking about in particular:

1a.) Being. A being exists just as a pair is even, i.e. by definition. But while some group that is by definition even can cease to be even by ceasing to be, what by definition exists can’t cease to exist. The individual we could call a being could only be an individual whose non-existence would involve a contradiction. This is no individual in the universe (all of them have a genesis) nor the universe (which is not an individual but a collection)

2a.) True. A thing is true when it exists relative to an intellect, but a thing only exists relative to a creator.*

2b.) Power. Power is the ability to be responsible for the existence of another.


3a.) Good. A good satisfies an appetite and so the highest good satisfies the highest appetite. But everything desires to exist and all intellects desire truth, and both of these terms are divine from 1 and 2.

Corollary 1: what we seek for ourselves requires going outside ourselves. The desire to for existence  is not limited to our mere desire not to die.

Corollary 2: Here is another vantage point to see the shallowness of understanding divine goodness as “moral perfection”

3b.) Dignity. Dignity belongs to a thing so far as it is an end and not a means. But the highest good, as such, can never be a means but only an end.

3c.) Person. If the person is subordinate to a non-personal highest good then objectification, alienation and the degradation of persons are the highest good of a person. The consequent is a contradiction, therefore, etc.

1b.) Life. To live is to exist in what acts for itself. But a person acts for himself.

4.) One. One is the negation of division, but things are divisible so far as they await some further existence in space, in time, or of their intrinsic matter. But to await further being, as such, is not to be.

5.) Devotion. The limit of devotion is worship. 


Objection: Being heard does not require existence to a divine ear, so truth does not require existence to a non-divine mind.

Reponse: This illustrates the difference between the objectivity of sense and of intelligence. Sense objectivity is content to attain the thing as it is for the one sensing. Whether you’re a dung beetle or not will affect you awareness of sweet-smelling things, whether you are a polar bear or not will affect what temperature is too cold or oppressively hot. But intelligence seeks an objectivity that is just the thing itself and nothing more – the pure object unconditioned by subjectivity. But to attain this requires a pure “being seen” from no perspective, i.e. from no limited vantage point. What we mean by objectivity, and so truth, cannot involve a vantage point within the things we seek to understand.

This allows another development:

2c.) Beauty. The beauty appropriate to this sort of thing is sublimity, and the sublime is that which overwhelms the cognitive powers. But perfect objectivity totally overwhelms all created cognitive powers, therefore.


Perseity and the Fourth Way, Part III

… Aristotle develops Plato’s account of perseity as “communion” into an account of the various relationships of universality between the subject and the predicate. We can first note that some predicates are said of all instances of some subject. Such predication seems to always involve perseity, though it need not be made explicit. In looking for an explanation of malaria, for example, we might notice that all cases of malaria arise from being near swamps, but this does not mean that it getting malaria and being near swamps considered precisely as such have a per se relation to each other. We can observe, for example, that the two are connected always or as a rule without being convinced that there is any intrinsic feature of a swamp that is the direct cause of malaria.

A more fundamental relation between subject and predicate is one that exists between them in virtue of something intrinsic or per se to them. For example, we don’t just believe that fire and its heat are simply together as a rule, we are also convinced that there is something intrinsic to fire that makes this so. Again, we do not just observe cones being a third of the area of the cylinders that contain them, we also can see that it is an intrinsic feature of the cone that makes this the case. We are (perhaps) not entitled to hold that these particular convictions are indefeasible, and perhaps either one is open to being overturned by the discovery of a cold fire or a new and more complete theory of geometry, but to be mistaken about which features are intrinsic to things is not the same thing as to deny that we can come to know any intrinsic features of some subject. At the bare minimum an intrinsic feature is a heuristic that guides our explanations of things from what merely happens to be so towards what must be so.

Aristotle’s account of the per se is based on the more fundamental axiom that our explanations of what things are must start off confused and imprecise and gradually be made more complete. Malaria does not come to us with a label or tag that tells us exactly what place to look for it or how we are to consider any of the objects in that place. It might first be related to being in hot climates; and then not to a hot climate as such but to hot areas with swamps; and then not to the swampiness of the place as such but to an extrinsic feature of swamps (sc. that mosquitoes adapted to use them as ecosystems); and then not to mosquitoes as such but to the fact that mosquitoes both carry and transmit a certain parasite. Notice that, with each progressive development in our understanding, we might be relatively convinced that we have found malaria as such. We might be convinced that malaria is just a peculiar way of being weakened or broken down by heat, just as some people still believe that colds are a peculiar way of being weakened or broken down by the cold. Again, we might be convinced that malaria is just a swamp fever, or that it is caused by something either intrinsic to swamps (e.g. their brackish) or something else. Every stage in this process might be supported by evidence to the point of convincing a rational observer; but for all that, we can recognize from our comfortable perch as outside observers that we have not found malaria itself until we have found the parasite. This terminal point of the explanation is simply when we reach to what the thing is in itself, that is, when we come to get a distinct look at the thing which we first understood only nominally and in a confused way.

Notice that on this account of explanation it consists in moving from some X to an account of what X is intrinsically or in itself. Explanation does not terminate in some brute fact in the face of which we can say nothing more than “it just is that way”, but rather in moving from something that is merely named to what the thing named is in itself. The explanation does not end with a shrug that can do no more than accept that “all explanations have to stop somewhere” but with the conviction that we have actually found the thing which we had initially done no more than name. The simplest account we can give of this sense of explanation is that it consists simply in discovering what we mean. We meant something by malaria, but this initial meaning occurred in a jumble of confused facts that required a difficult process of discovery and many sophisticated theories and tools to discover that malaria itself is the name for a mosquito-borne parasite.

Because this account of explanation is based on the general fact that explanations move from the confused to the distinct, every sort of cause will admit will move from some X that is merely named to the X itself. For example, the if we witnessed the first atomic attack on Hiroshima, we would want to know who was responsible for it and so we would be looking for an explanation in the order of agent causes. Now notice that the first person we could actually see dropping the bomb would be the bombardier on the plane, though it would be pretty easy to establish that he only dropped it at the behest of the flight commander. But neither of these persons is who we are looking for when we ask who is responsible for the event, but  only the one who was responsible for all of them doing what they did, sc. Harry Truman. Likewise, if we caught the Watergate spies, they would be the first persons we knew were responsible for the break in, but they would not be the ones we are looking for when we ask who is responsible for the break in.

Just as there is a long series of diverse subordinate agents there is a corresponding series of distinct goals or final causes: the bombardier was only intending to pull a lever at the proper time while Truman had the much broader motive of terrifying his enemies into unconditional surrender. Here again, explaining a fact consists in discovering who we mean when we consider “the one responsible for this” or what motive we are looking for when we ask “why did this happen?” Truman is not a brute fact explaining why the bomb dropped, he is the one we meant to talk about from the beginning when we spoke of the one responsible for the action. Again, it is ridiculous to say that the explanation of motives “breaks down” after we discover the motive to terrify the Japanese into submission, since this would be like saying that our ability to look for something “breaks down” after we find it.

On this account of explanation, the explanans is simply “the thing itself”: e.g. malaria itself is the parasite as opposed to any other environmental feature, the one who dropped the bomb was Truman himself as opposed to any of his subordinates. Though speaking of a “thing itself” certainly suggests the familiar Platonic theory, Aristotle’s account of explanation is a complete redefinition and repudiation of it. The things themselves are not separated entities, or even forms inhabiting matter, but just the precise realities that we first target in our merely nominal and confused accounts. The trajectory of explanation is not from the facts to a form that is outside of them but from a name which we impose in the midst of a confused awareness of facts to a thing among those facts that actually deserves the name. The thing itself – or the thing per se – is not given separately from what we start with, but within what we start with, though indistinctly.

Aristotle distinguished two senses of perseity. In the first, any intrinsic connection between a subject and predicate will be a per se connection. In this sense, when we say an exothermic reaction is hot we say something per se, since it falls in the very definition of exothermic reaction that they give off heat. There is, however, a stricter sense in which it is not precisely the exothermic reaction that is hot, but only the mean molecular motion, since it is only this latter that is precisely what heat is, and it is in virtue of exothermic reactions giving rise to such motion that they are hot. Aristotle called the looser sense of the per se kath’ auto, which can be unproblematically translated as  “per se”, but he called the stricter sense katholou (or “universal” in the genitive case) which we will here call primo since this was the Medieval usage. It is this strict sense of the per se – the per se and primo – that we target when we seek to explain something, even if, for practical reasons, we are often content with explanations that fall short of this level of rigor.

The Per se and Primo in The Fourth Way


Any causal explanation targets the primo and per se, and all cosmological arguments are a causal explanations of various things manifest to sensation. We can see that the Fourth Way is appealing to this principle because it twice appeals to the Medieval theory of fire as the cause of what was hot, which the Medievals saw as the per se and primo cause of heat, in exactly the same way that we now see mean molecular motion and the per se and primo cause of heat. It is crucial that we describe the Fourth Way as reaching, for example, what is per se and primo good, true, etc. because there are all sorts of things that are per se good – virtue, charity, food, and even everything that exists – which are nevertheless not good such first. This is why it is not enough to appeal to a principle like “things that are participated reduce to things that are essential”. Just as a thing can be essentially hot without being what is hot first, so too a thing can be essentially good without being what is good first of all.[1]

St. Thomas places the principle that the causal explanations reduce to some first in at the logical beginning of his cosmological arguments, though he first applies it to the special case of a first cause of motion, saying that a series of causes cannot be infinite because: “then there would not be a first mover, and it would follow that there would be no other movers, since a second mover does not move except by the motion of the first mover, as a stick does not move unless it is moved by the hand.” [2] St. Thomas’s example is clearly from the order of efficient causes, and we saw above that the a first cause is necessary in this order since such a cause arises simply from giving a distinct account of what one means in speaking about “what is responsible for the motion”. One simply can’t mean to speak about an instrument or something with a derivative responsibility for an action when he asks about what is responsible for an action. Doing so would be like answering a child who asked “why are we driving to Church?” by saying “because I’m pointing the car towards it”. To ask the question about my what intention is responsible for the action means asking about what is responsible first of all. Any other explanation explains only in a qualified sense, and is in some way an indistinct grasp of the facts.[3] While it is true that there are all sorts of reasons why we do not press our questions to completely distinct answers – reasons ranging from practical concerns to the dimness of our intellect to the desire to restrict ourselves to a limited domain of explanation – nevertheless St. Thomas is claiming that the completely distinct answer to “what is responsible for the stick moving” is “God”.

The Fourth Way starts from no specific class of facts, but from any fact about the world which, when understood per se and primo, deserves to be called God. St. Thomas need not be seen as restricting himself only to “transcendental perfections”, as the manual Thomists have read him. The Fourth Way can, in fact, start with things given in all the other four proofs, and can reach all the conclusions they reach by its own proper way of proceeding and without appeal to any extra premises. For example, we see movers that are more and less immobile, and so there must be some mover that is immobile per se and first; we see causes that are more and less causal, so some cause must be per se and first; and we see necessary things that are more and less necessary, and thus there is something whose necessity is per se and first. If such a being is “what all call God” in the preceeding proofs, it is also in this case.

Reading the Fourth Way in this way leads to several good results, which I will here only sketch in outline:

It gives the proof scientific value, even in the contemporary sense of science. The Fourth Way, as we have continually stressed, appeals to a principle that is common in all causal explanations, not just those that are supposedly metaphysical, but also those that are scientific, or medical. We are looking for the per se and primo just as much when we are looking for the cause of malaria or diabetes[4] as we are when we are looking to establish the existence of God. This explains why this proof is uniquely concerned with proving its relation to the empirical and scientific, not only by twice appealing to the Medival account of the per se and primo cause of heat, but also by referencing De Caelo et mundo, an essentially Astronomical book.

It gives a simple and elegant account of the analogy of names from creatures to God. On our account of the per se and primo, it is the end point of an explanation that starts from something that is merely named and moves to something most deserving of the name. But this how St. Thomas divides analogous names from univocal and metaphorical names in the Summa theologiae. If, St. Thomas says, we consider the thing we impose the name on first then we will call the creature “good” or “existent”, but if we consider what the name signifies, then we see goodness and existence as belonging not to the creature but to God. Words like “good” or “existent” can be understood as naming either the things we first grasp in an indistinct and simply nominal manner, and in this sense we “mean” to indicate creatures when we speak of them. But we can never mean to indicate the indistinct and secondary as such in a causal explanation, and so in the proper sense of meaning or signification we do not signify the creature. It is precisely this double sense of meaning, arising with respect to a single word, that gives rise to the diverse proportional or analogous names that are said of God and creatures.

It can contribute to a larger dialogue about the explanatory necessity of form. Though Thomists frequently lament that the modern sciences have apparently cast out all formal and final causes, they have not yet come up with a principle actually useful to modern science that points to the explanatory power of form. But an understanding of perseity seems to be just such a principle, for it reduces causal explanations to something “in itself” or “of itself”, which have been, since Plato, unmistakable references to formal causality; and such causes become final causes as soon as we recognize the role that they play in a causal process that brings them about.


[1] This premise seems to be particularly important to preserve the real integrity and perseity of creatures, and to keep a proof for the existence of God from negating their proper existence. This problem becomes particularly acute when we consider the question of human freedom in the face of the causal power of God; though, as we have just seen, there is no problem with saying that the creature is essentially free and even autonomous, we only deny that this essential freedom is the first such essential freedom.

[2] ST Note that the principle that causal explanations reduce to some first, though it occurs temporally at the end of the argument, is logically the first premise of the argument. No other principle or truth in the argument is more general. This general conclusion about causes is presupposed in the subsequent proofs.

[3] It’s interesting to note that some explanations are explicitly targeting means, and so are targeting things that are in themselves secondary. But even when we ask these “how” questions in the order of means, we are still we are asking for something that is first. A catapult, for example, in an instrument that uses a rock as an instrument to destroy things, but if someone asks “how did we destroy the city wall” the answer is not “with rocks” but “with catapults”. If we said only the first, we would mean that the rock was our primary instrument, i.e. that we held it in hand and hammered the wall, or hurled it at the wall with our bare hands.

[4] The recent finding of the ATP/P2X7R pathway by researchers at Boston’s Children’s Hospital is simply a finding of the per se and primo cause of diabetes

« Older entries