Summa Theologiae I, Q22, and SCG III.71-74
 
God’s providence means that God is intelligently ordering all things toward their ultimate end. To do this, it is not sufficient that He simply create things—He must also order their interactions. Since God is the cause of the whole creation, He necessarily moves the whole creation to its ultimate end, which consists in good overall order.
 
Agents order their actions to some ends. Since God’s action extends all the way to every detail of creation, every such detail must be ordered to God’s ends. God’s knowledge and agency extend to particular things, and not just to general kinds of things. And, as we saw last time, His agency always produces definite effects.
 
In reply to objection 1 of article 2, Thomas embraces the radical conclusion that there is nothing that happens by chance in relation to God, since all the eventualities are foreseen by God. It seems to me that this moves too fast. It is true that all coincidences are foreseen by God, but it doesn’t seem to follow that they cannot happen by chance. If a coincidence is the result of God’s moving two or more things toward distinct ends, and neither of the ends entails the coincidence, then it seems that we could call the coincidence a matter of chance, even if God foresees that it would happen. God can foresee something as happening without intending it either as a means or an end.
 
In his reply to objection 2 in the same article, Thomas argues that God permits all of the defects in creation for the sake of some good of the universe as a whole. For example, lions would cease to exist if there were no slaying of animals. I don’t think that this entails (or is meant to entail) that this is the best of all possible worlds—merely that there must be some reason for the existence of all of the privations within creation. As Augustine said, God is able to bring (some) good from evil, but it doesn’t follow that each evil is necessary in order to maximize total goodness.
 
I question whether Thomas has established that there is such a thing as the “good of the universe.” The universe, or the totality of creation, is not a single substance. Consequently, we can’t be sure that it has its own final cause or natural end. Created things have a common end – which is God’s glory, the manifestation of His self-diffusive goodness, but that doesn’t imply that they collectively have a single end, as Thomas seems to assume.
 
There are three plausible candidates for a global good or end: justice in the distribution of benefits, the variety of modes of participating in God, and the overall beauty of the universe. On the first point, it seems plausible to think that things must already form a unity or a system of some kind, before the question of justice can even arise. If there are rational animals in the Andromeda galaxy, for example, does it make sense to ask whether God has exercised distributive justice in giving goods to them and to us? Can we ask whether God has exercised distributive justice between me and a vein of coal in Pennsylvania? On the second point, I’m not sure that variety as such is a good. It seems to like the finitude and definition that is generally required of goods—there is no maximum degree of variety that the world could contain. Perhaps it is better to say that God created each kind of thing simply because it is good for such things to exist, with variety as a mere by-product. And in the case of beauty, it seems that something must possess a certain kind of unity in order to count as beautiful. I will grant that a plurality of substances can be collectively beautiful, like the stars in the earth’s sky, but there must be at least a unified standpoint from which the collective can be considered, and I’m not sure that there is such a thing with respect to the universe as a whole.
 
The question of whether the universe as a whole has its own end or value is important. Thomas infers that God’s providence consists in a kind of unified plan or blueprint for the entire cosmos, rather than a library of plans or intentions for each substance and unified system of substances. One might respond: if God has multiple plans or intentions, must He not coordinate them, to avoid internal conflict in His intentions? Yes, but coordination isn’t the same thing as consolidation. We can imagine, I think, a plurality of divine plans existing in a degree of mutual contingency and independence from one another.
 
If God has a single, unified plan for creation, then it must have been in effect from the very first moment of creation. Since God’s plan is necessarily effective, and if (as St. Thomas teaches) the plan is complete in every detail, it is hard to see how this can be compatible with genuine contingency in the future. In contrast, if God has multiple, mutually compatible plans, then there is no reason that such plans could not come “on line” at different points in history. Such a plan goes into effect as soon as its earliest elements are actualized, but not before that point. Prior to actualization, the plan would be contingent relative to the events so far realized. Of course, all the plans are equally in effect from the perspective of God’s eternity, but that should be compatible with a changing status relative to the progress of time.
 
William of Ockham introduced a useful distinction concerning future facts. Some of these are hard facts and others are soft. So, for example, let’s suppose that it is genuinely a matter of contingency whether the Astros win their pennant this year. Let’s suppose that in fact they won’t. Then the truth of the statement ‘The Astros won’t win the pennant in 2021’ is a soft fact about the future. In contrast, let’s suppose that God has determined that one day the Anti-Christ will emerge. Then the truth of the statement ‘The Anti-Christ will emerge’ is a hard fact about the future. All facts about the present and past are now hard facts. So, it is now a hard fact that dinosaurs once lived or that the Astros won the 2017 World Series. Similarly, Ockham argues, facts about God’s will and knowledge concerning the future can be either hard or soft. As time passes, some of these facts harden. This does not involve any real change in God, since His act of will and knowledge is not internally modified by their objects.
 
In the reply to objection 4, Thomas considers the problem of reconciling human freedom with divine providence. He argues that human freedom consists in the fact that human beings are not naturally determined to a unique course of action in each circumstance. This lack of determinism applies only within the created order—it does not exclude God’s unique mode of causality (primary causation). “Everything happening from the exercise of human freedom must be subject to divine providence.” God’s providence extends in a “more excellent way” to the just than to the wicked. He can be said to have “abandoned” (dimittere) them, although they are not altogether excluded from His Providence, since that would mean their annihilation.
 
Reply 5: “Since a rational creature has, through its free will, control (dominium) over its actions, it is subject to divine providence in an especial manner (speciali modo).” I think this means that God’s agency does not exclude our own “control” or dominion over our actions. Instead, as I suggested before, we exercise a kind of joint dominion, neither excluding the other. When we do wrong, this is imputed to us and not to God as fault, because of the difference in our respective intentions. Compare Genesis 50:20 (Joseph to his brothers): “But as for you, you meant evil against me [by selling me to the Egyptians], but God meant it for good, in order to bring it about as it is this day, to save many people alive.”
 
In article 4, Thomas explains that at times God governs the creation through intermediaries. This reflects God’s strength and not His weakness. It is not that He needs such intermediate causes, but that He further enhances the glory of His creation by bestowing on creatures the dignity of real causality.
 
The role of secondary causes in explaining evil is explained by Thomas in SCG I, chapter 71. A defect that is produced by some secondary or instrumental cause is not always attributed to the primary cause. Think of a skilled artisan using a flawed tool.
 
But isn’t God responsible for any defect in His secondary agents? No, because all creatures are necessarily “defective” or imperfect in some respect. No rational creature, for example, can take into account every possibly relevant factor. Moreover, the excellence of creation requires that creatures exist at a variety of levels or grades of excellence.
 
The goodness of God’s government of creation requires that He allow things to work according to their own, limited nature. Otherwise, creation would be a kind of sham, a world of mere shadow-boxing.
 
It is interesting that Thomas never appeals in these articles (as far I can tell) to God’s timelessness, in the way that Boethius does in The Consolation of Philosophy. Neither does Thomas bring to bear the implications of his strong doctrine of creation—namely, the fact that the content of God’s will and knowledge are extrinsic to His own being. He does insist that God’s causality of future things does not take away their real contingency in the circumstances, but he does seem to think that future contingencies are already in some way certain and immutably fixed. However, I don’t think that this follows. From our point of view, within the flow of time, future events are really and not just apparently contingent and indeterminate. It is true that for God (in eternity) all things happen “at once”, past, present, and future, but that does not contradict that fact that at the present time the past is fixed and the future is largely “open”. If a future event is really now contingent, then so is God’s eternal knowledge and will with respect to that event. As time passes, God’s will gradually shifts (in its objects) from contingency to necessity, but this is merely a Cambridge change in God, with no intrinsic modification required.
 
God can make certain future events necessary, by promising them to us or by inspiring prophets with infallible foreknowledge of them. So, for example, Judas’s betrayal and Peter’s denials were fixed in advance by prophecy, as was Cyrus’s decree to allow the Jews to return to Canaan. Similarly, the future advent of the Anti-Christ, and the Second Coming of Christ are fixed and certain. But much of the future is genuinely open to alternatives, depending on our choices and chance events.
 
To clarify this point, let’s look at Peter van Inwagen’s consequence argument for the incompatibility of free will and determinism. I will modify van Inwagen’s argument to make it apply to God’s Providence, conceived of as a fixed and comprehensive plan for the future.
 
1.God has (in eternity) a Plan according to which I will do x tomorrow (where x is some arbitrary free action of mine).
2.It’s not currently up to me whether God has such a plan.
3.Necessarily, if God has such a Plan, then I will do x tomorrow. (God’s providence is infallibly effective).
4.Therefore, it’s not currently up to me whether I will do x tomorrow. (By 1-3 and van Inwagen’s transfer principle)
 
I think we should deny that premise 2 is generally true. Whether I do x tomorrow can be both up to me and up to God, and there is no determinate divine Plan already in effect that settles the matter one way or the other. To think that God has to plan ahead in order to govern the creation with coherent providence is to be guilty of a kind of anthropomorphism. God is infinite in wisdom, and so He can do whatever “planning” is needed on the fly, so to speak.
 
Presumably, God has some plans about creation that are not currently up to me. For example, His eternal plans about what happened in the past are currently beyond my control. Let Plan-Minus stand for the sum total of God’s plans that are currently beyond my control. Here’s another version of the consequence argument:
 
1.It’s not currently up to me what God’s Plan-Minus contains. (By definition of Plan-Minus)
2.Necessarily, if God has Plan-Minus, then His comprehensive Plan for all of history must include my doing x tomorrow. (Any initial segment of God’s Plan entails all of its successive elements.)
3.Necessarily, if God’s comprehensive Plan for all of history includes my doing x tomorrow, then I will do x tomorrow. (God’s providence is infallibly effective).
4.Therefore, it’s not currently up to me whether I will do x tomorrow. (By 1-3 and van Inwagen’s transfer principle)
 
Once again, I think we should deny 2. This is where it is crucial to determine whether God has simply a single Plan, each part of which requires all of the other parts, or whether God has multiple partial plans that are mutually contingent. If the latter, then we can ask when a particular partial plan has become the external object of God’s will. We can ask, for example, when a particular person became elect or reprobate, and we can ask what contingent events contributed to this fact.

In the Summa Theologiae Q4, a1, Thomas gives just one simple argument for concluding that God is perfect: namely, the fact that imperfection always implies some lack of actuality, and God is actuality in its absolute fullness. His reply to objection 3 is also noteworthy. Objection 3 observes that ‘existence’ seems radically imperfect, since things can exist no matter how far they are from perfection. Since God’s nature is simple, unqualified existence, He would have to be the most imperfect thing of all.
 
In the Reply, Thomas rejects this greatest common factor conception of ‘existence’. It is true that the formula ‘X exists’ can be true, no matter how minimal X’s grip on existence may be. (Thomas calls this the ‘formal principle of existence’, by which he seems to mean its logical or semantical role.) However, Thomas urges us to focus instead on the metaphysical role that is played by acts of existence (actus essendi). It is the act of existence that gives each thing whatever degree of being it has. The act is limited by the nature or essence of the thing, not vice versa. Acts of existence are the source of reality and actuality. Hence, God, as the supreme act of existence, must contain eminently every possible degree of being, so that He can give to each individual act of being all the actuality it needs to do its work, given its associated essence.
 
In article 2, Thomas argues that God possesses all the perfections had by creatures. This is the crucial point at which we depart from purely negative theology. He gives two arguments: one from God’s place as First Cause, and the other from God’s essence being His pure existence. First, since God is the cause of all the perfections in any creature (not only in the actual world, but also in any alternative possibility), God must possess in an eminent form each of those perfections. This is an appeal to the principle of proportionate causality which we’ve seen repeatedly since the First Way. As Thomas explains, the fact that the sun is the cause of heat does not entail that the sun is formally hot. But it does entail that it contains heat eminently—that it has some attribute that is, by virtue of its greater nobility of being, capable of making other things formally hot. Similarly, God is the cause of all heat, but He is not himself formally hot. How, then, is He eminently hot? He is so, as we shall see, by being an Intellect, knowing the form of heat as one of His possible creations. This is the same sense in which an architect is eminently a house.
 
So far, we have not really moved very far from a negative theology, since to say that God is eminently F is really to say little more than that He is the cause of F-ness. The second argument is, I think, the more fruitful. God’s existence is unlimited by any distinct form or essence. He is thereby a case of pure, unqualified existence. For the moment, let’s define a perfection as a property that doesn’t explicitly entail that its bearer is not God (not the First Cause, not identical to its own act of existence). So, for example, being finite, being created, having a nature, having passive potentiality—none of these would count as perfections, since they all entail explicitly that their bearer is not the First Cause. In contrast, being powerful, loving, knowing things—none of these explicitly rule out being God.
 
Say that F is such a perfection. If God lacked the possibility of being F, then being itself would lack this possibility. If F were not absolutely impossible, and if F does not explicitly rule out being God, then it would have to be possible for God to be F. There could be then no explanation of the impossibility of God’s being F: F itself does not rule this out, and God has no nature but existence, so if His nature rules it out, there must be a fundamental incompatibility between existing and being F. So, God must be possibly F.
 
But God lacks all passive potentiality. Hence, it is impossible for God to be merely potentially F. If He can be F, He must actually be F. Consequently, God must possess every perfection.
 
The basic premise of this second argument is that impossibility must have some explanation. If F and G are both purely positive, then there could be no logical inconsistency between them. Hence, is must be possible for F and G to be combined. Existence as such is purely positive. Hence, existence can be combined with any purely positive property. Since God’s nature is nothing but existence, it must be possible for God to have any purely positive property. Since God is a being of pure actuality, He must have in actuality every purely positive property.
 
We saw, when considering the Third Way, that Thomas seemed to assume that the possible existence of something that doesn’t actually exist needs to have an explanation. There is some prima facie tension between that principle and the principle relied on here. Suppose that there is no explanation for the possible existence of p, and no explanation for the impossibility of p. Is p then possible or not? The Third Way would say No, and the argument from perfection would say Yes. But p can’t be both possible and impossible.
 
The two principles can be reconciled in the following way. The Third Way appeals to the Nihil ex Nihilo principle:
 
(NEN) If x does not actually exist, then x’s existence is possible only if there is something that actually exists with the actual power to cause x to exist.
 
The second perfection argument depends on the principle that logically consistent combination is always possible:
 
(LCC) It is impossible to combine two properties only if there is some logical inconsistency between their essential internal structure or definition.
 
Are the two principles consistent? Consider some x that does not actually exist. Now consider two properties: actually existing, and being x. These are clearly not logically inconsistent in their internal structure or definition. So, by LCC, it must be possible to combine them. This means that x’s existence is possible. By NEN, it follows that something has the power to cause x to exist. But this is true: God exists and has this power. What’s interesting is that these two principles by themselves seem to entail that in every possible world, something exists with the power to cause the existence of anything that doesn’t exist in that world. This isn’t quite a proof of God’s existence, but it’s close. This does suggest that many atheists will find either NEN or LCC implausible. One could mitigate this problem by restricting LCC in such a way that it doesn’t apply to properties like being x (some particular thing). We might limit LCC to potentially general properties, properties that could in principle be instantiated by more than one thing. Then the atheist could consistently accept both principles.

My colleague and friend Dan Bonevac has discovered a new interpretation the Third Way that resolves the problems that have puzzled readers from medieval times. The argument seems to involve two highly problematic claims:
 

1. If it is possible for a thing not to exist, then there must be some point of time at which the thing does not exist in reality.
2. If for each thing in some class C there is some time at which it does not exist, then there is a single time at which nothing in C exists.

 
Dan proposes that we interpret the temporal adverbs in the argument (quandoque, aliquando, modo) as modal rather than temporal modifiers. Such an interpretation is quite natural in many (if not all)  languages, including Latin and English. Dan notes that St. Thomas never uses the word 'time' ('tempus') or any other explicitly temporal term. In fact, if we look at the parallel argument in the Summa Contra Gentiles (I.13, paragraph 33), we see a complete absence there of temporality. Under this interpretation, the two problematic claims become:
 

1. If it is possible for a thing not to exist, then there is some possible situation in which it does not exist.
2. If for each thing in class C, there is some possible situation in which it does not exist, then there is a single possible situation in which nothing in C exists.

 
Now principle 1 is simply a tautology of modal logic. Principle 2 is still a substantive principle, but it is a quite plausible one, as we shall see.
 
Here is the Third Way under this modal interpretation:
 
Here’s the Third Way under this interpretation:
 

1. There are contingent (non-necessary) beings (because we see things coming into and going out of actual existence).
2. That which is contingent is non-existent in some possible world. (Modal logic)
3. Suppose for contradiction that all actual beings are contingent (non-necessary).
4. Given 2 and 3, there is a possible world in which nothing exists.
5. If it were possible for nothing to exist, then nothing would exist in the actual world.
6. Since it is impossible for something that doesn’t exist to exist as a possibility except by the causal agency of something actually existing. (Nihil ex nihilo)
7. But, obviously, something exists in the actual world (namely, the contingent things mentioned in premise 1).
8. Therefore, by contradiction (of the hypothesis in line 3), some actual being is a necessary being. (From 3-7)

Now everything is crystal clear, except for premises 4 and 5. Dan shows how we can construct, using resources available to Thomas Aquinas, plausible arguments for each. He calls premise 4 the “Annihilation Lemma” and 5 “the Dead End Lemma”.
 
Proof of premise 4: the Annihilation Lemma.
 

1. Suppose that everything is contingent in the actual world, w0.
2. Necessarily, all causal chains are finite (no regresses or cycles).
3. So, there are uncaused contingent things in w0. Let the xx’s be the plurality of those things.
4. Subtraction rinciple: if a world x contains one or more uncaused contingent things, then there is a world y in which those things do not exist, and the set of uncaused things in y is a subset of the set of uncaused things in x (i.e., no additional things exist uncaused in y).
5. So, there is a world w1 in which none of the xx’s exist, and such that the set of uncaused things in w1 is a subset of those in w0.
6. Since the xx’s are all the uncaused things in w0, this means that the set of uncaused things in w1 is empty.
7. However, if all causal chains are necessarily finite, then a world with no uncaused things must be an empty world, a world in which nothing exists.
8. So, w1 is an empty world.
9. So, it is possible for nothing to exist.

 
Proof of Premise 5: The Dead End Lemma
 

1. Suppose that w1 is an empty world.
2. Something can possibly exist relative to world w only if there is something in w that can cause it to exist. (A causal principle: Nihil ex Nihilo)
3. So, nothing can possibly exist relative to world w1.
4. The actual world is necessarily possible. (Axiom B of standard modal logic)
5. So, the actual world is possible relative to world w1. (4, definition of necessity)
6. So, nothing exists in the actual world. (From 3, 5)

 
Why think the Subtraction Principle is true? Suppose that there is an uncaused thing x which, if deleted from the world, necessitated the introduction of a new uncaused thing y in its place. In that case, it seems that the existence of y in the new world would be caused by the absence of x (together with the other conditions that, jointly with the non-existence of x, necessitated the existence of y). This is doubly problematic. First, and most importantly, because we seem to have a contradiction: the existence of y would be both caused and uncaused. And, second, because it doesn’t seem that the existence of anything could be wholly caused (or explained) by the non-existence of something else.
 
This version of the argument requires two causal principles: (i) necessarily, every causal chain is finite, and (ii) necessarily, it is impossible for something to exist unless (a) it actually exists, or (b) it could be caused to exist by something that actually exists. The second principle (Nihil ex Nihilo) is pretty strong. It would imply (given S5 modal logic) that every contingent thing in the actual world has a cause in the actual world. Here’s the proof. Suppose for contradiction that x is contingent and uncaused in w0 (the actual world). Consider any possible world w1 in which x does not exist. The existence of x is possible but not actual in w1 (by axiom B), so by Nihil ex Nihilo there must be some y that exists in w1 and is capable of causing x to exist. This plausibly entails that, in any world w in which x does exist, x is caused to exist by some y that also exists in w. Hence, since x exists in the actual world w0, x must be caused to exist in this world, contrary to our original assumption.
 
An interesting question: could we do without the first causal principle (namely, no infinite regresses or cycles)? Here’s a possible way of doing so. Suppose that there are infinite series or cycles of contingent things. We could plausibly strengthen our subtraction lemma, so that it allows for the simultaneous subtraction of all uncaused contingent things and all infinite contingent series and cycles, without requiring the addition of any new uncaused things or any new infinite series. If so, we could run the original argument without the first principle