On Three Problems of Divine Simplicity

Alexander R. Pruss

1. Introduction

The Fourth Lateran Council teaches that God is a “substantia seu natura simplex omnino”—an “altogether simple substance or nature”—and the First Vatican Council reiterated the teaching. The doctrine of divine simplicity is at the center of Thomas’s natural theology, since it is essentially involved in his attempt to show that the First Cause that he has proved to exist in the Five Ways has the appropriate divine attributes.

The doctrine claims that there is no ontological composition in God of any sort, whether of matter and form, or of essence and accident, or of this attribute and that attribute considered as ontologically distinct. The doctrine is a traditional part of Christianity and Judaism, though I understand that Islam may have ultimately rejected it.

Divine simplicity, like the complementary doctrine of the Trinity, leads to intellectual difficulties. I will talk about the three most major ones that arise within the context of natural theology.

The first problem is that it appears incomprehensible how we can meaningfully predicate different attributes of God, such as “perfect mercy” and “perfect justice” which will be my stand in for any pair of prima facie distinct attributes. For according to the doctrine of divine simplicity when God has attributes A and B, then God’s being A is ontologically identical with God’s being B. The difficulty is that under such circumstances “mercy” and “justice” seem to lose their ordinary language meaning and since our linguistic usage is based on ordinary language, it becomes meaningless to use the terms about God. This is the “multiple attributes” problem.

The second problem comes from noting that the doctrine of divine simplicity entails that in some relevant sense God has no intrinsic contingent properties. I have no definition of an “intrinsic property”, but we can get a rough and ready understanding of what is meant when we think about paradigm cases such as the lump of coal’s containing such-and-such a number of carbon atoms or Fred’s being in horrible pain, as contrasted with extrinsic properties such as John’s being taller than Fred, Bush’s being President, and so on. If God had an intrinsic contingent property A, then A would be a property that in some possible world God lacks. But God plainly has at least one non-contingent property, B, such as being God or being good. We could then ontologically distinguish God’s having A from God’s having B, because the one occurs in all worlds where God exists and the other does not, contrary to divine simplicity. The problem now is that although God has created this world, he could have created another—or none at all. But willing one thing rather than another seems to be an intrinsic property, and if God’s willing that this world exist is contingent, then it seems to follow that God has a contingent intrinsic property.

The last problem is what God believes differs between possible worlds: in one world he believes that there are horses and in another that there are no horses. But it seems that believing that p is an intrinsic property of the believer, and hence again that God has a contingent intrinsic property.

I will not solve the three problems in the sense of showing how it is that it is possible for God to be merciful and just, able to do different things and able to believe different things while being simple. I think the full solution would require a vision of God’s essence. But I will sketch some reflections that puncture the notion that these problems show an evident contradiction between divine simplicity and divine attributes.

2. Justice and Mercy

The doctrine of divine simplicity had better not say that mercy and justice, in general, are one and the same property. For that would make meaningless a claim that a friend of ours had exhibited more mercy than justice in some situation. Rather, the claim is that God’s mercy and God’s justice are the same ontologically.

What makes it be true that Socrates is just? Surely it is something about Socrates, something that we might reasonably denote by “Socrates’ justice”, id est “that in virtue of which Socrates is just”. Socrates’ justice is not the same as Plato’s justice, because if they were the same, then the same thing would make it be true that Socrates is just as would make it be true that Plato is just. But if that were so, then it would follow that, necessarily, if Socrates is just, then that in virtue of which Plato is just exists, and hence Plato is just.

I am not assuming here that Socrates’ justice is a self-standing quasi-substance. Socrates’ justice likely is a dependent being: its esse is inesse—Socrates’ justice is precisely by Socrates’ being just. What I said so far should have been neutral between any forms of nominalism, trope theory or Platonism that have a chance at being right (even Platonism should admit that there is the Form of Justice and there is Socrates’ participating in that Form).

Consider Bob who is a rock and who is hot. Bob’s heat just is a lot of movement of Bob’s molecules. Bob is hot precisely because of this movement: whenever Bob’s molecules—identified as such—are moving a lot, Bob is hot, and that it is hot just is that its molecules are moving a lot. Bob’s heat is distinct, then, from the heat of a different rock, Jane, and very different from the heat of the sun. There is an ontological basis for predicating heat of Bob: the movement of the molecules constituting Bob. It is this ontological basis for the predication that is “Bob’s heat”.

The claim that God’s being merciful and God’s being just are identical is, I take it, the claim that the ontological basis of God’s being merciful is identical with the ontological basis of God’s being just. Or, in the above terminology, it is simply the claim that God’s justice is identical with God’s mercy. This does not entail that Cato’s justice is identical with Mother Teresa’s mercy, or even that Mother Teresa’s justice is identical with Mother Teresa’s mercy.

So at least the doctrine of divine simplicity, when properly formulated, does not result in an immediate collapse of the perfections of human beings. But there still might be another argument against God’s being merciful being identical with God’s being just. For if the two are identical, then it seems that a theologian repeats herself when she says that God is merciful and when she says that God is just. Thus, saying that God is merciful and saying that God is just is like saying that Socrates is brave and that Socrates is courageous, from which one can once again conclude that, absurdly, mercy is justice, just as bravery is courage, and our language breaks down again.

However, there in fact do seem to be other cases where we have two properties, F and G, both of which are predicated of x and both of which are predicated of y, with x’s being F not identical with x’s being G, even though y’s being F is identical with y’s being G. Let F denote the predicate is round-or-triangular; let G be the predicate is red-or-triangular. Suppose x is red and round, while y is neither, but is triangular. Then, x and y both are both F and G. Moreover, x is F in virtue of its roundness while it is G in virtue of its redness, and its roundness and redness are plainly distinct. On the other hand, however, y is F in virtue of its triangularity and this triangularity is also that in virtue of which it is G. Given the sense which we gave above to the expression “being F”, it follows that y’s being F is identical with y’s being G, though x’s being F is not identical with x’s being G nor are F and G the same property.

This is just an opening gambit: the example is gerrymandered. Let’s go back to the justice and mercy case. A criterion of adequacy for our understanding what it means to say that God is merciful and just even though God’s being merciful is identical with God’s being just is, then, that there be something relevantly alike between God’s being merciful, say, and Mother Theresa’s being merciful. Moreover, there must be something relevantly similar between God’s justice and Mother Theresa’s justice. Yet, if language is not to break down, there Mother Theresa’s mercy and Mother Theresa’s justice cannot be relevantly similar. I will show how this can happen by telling a science fiction story where a similar thing holds.

There is a very strange alien—about whom I have told you nothing yet other than that he is very strange (and I suppose that masculine pronouns apply, with a long story needed to explain why)—that he hears. And suppose I also tell you that he feels, tactilely that is and not emotionally. By “He hears” I just mean “He has a sense of hearing” and “He feels” means “He has a sense of touch”—I do not mean to refer to specific instances of hearing or feeling one thing or another. I might then add: “I talked to the alien and he heard me. I then touched his seventh appendage from the top, and he felt that.” You no doubt would understand what I have said. However, it is important to note how limited your understanding would be. You would not be entitled to infer that the alien had a tympanic membrane that was made to vibrate by my speech, for instance. You might be able to infer that the alien has an ear understood as nothing more than an organ of hearing, but it might be radically different from our organs of hearing.

When we use terms like “hears”, “feels” or “ear” across very different kinds of creatures, we are speaking analogically. We are saying that there is something in that creature relevantly similar to hearing, feeling or an ear. Now, sometimes the relevant difference between cases is sufficiently great that an understanding of what it is to say that members of one group are F would not tell us what it is to say that members of another group are F. Thomas Aquinas calls such cases “equivocal predication.” In such cases, we might as well use different words in the two cases, though there might be a common origin of some sort. For instance, if our only understanding of “button” came from clothing fasteners, a sentence like “Click on the close button on the screen” would probably mean nothing to us. Of course, once we saw the screen, we might see a certain very vague physical similarity between the buttons used for fastening clothes and the close button.

But there are other cases where the predication is not equivocal but properly analogous, and where we do in fact understand what is being said, though our understanding is limited. Thus, even if we do not know anything about a Daphnia, not even that it is a crustacean, the claim that a Daphnia eats seems to have content. One has an understanding of what is said by analogy to familiar cases.

Let us return to our alien. You know basically nothing about him yet, other than that he is strange, that he has at least seven appendages and that he hears and feels. Suppose I let you know one more thing: the alien’s hearing is the same as his feeling. If you were impressed by the argument that divine simplicity rendered our concepts incomprehensible as applied to God, you would have to say that when I added this additional bit of information, I have undercut your understanding of what I was talking about when I said that the alien heard and felt.

But I submit that the understanding is not undercut by my additional claim. Rather, the claim underscores how little you in fact knew about the alien just by being told that he hears and feels. Not only were you not allowed to infer that he had a tympanic membrane, but you were not entitled to infer that he had distinct organs of hearing and touch. It is worse than that: for when we say that the alien’s hearing is identical with his feeling, we are not just saying that both are done by the same organ, the way the tongue both tastes and partially articulates sounds. Rather, we are saying that there is but one activity in both cases.

Our understanding of God’s mercy and God’s justice is rather like your understanding of the alien’s hearing and feeling at this point in my description of the alien. There is a genuine puzzlement about how the two features can be the same. And this puzzlement is due to the inability to get at God and the alien, to look and see how the two features manage to be the same. But we are not entitled to infer that it just cannot be so. We have a genuine puzzle, but we do not have a proof that the puzzle has no solution. And in the case of the alien at least, with some imagination, we might come up with an understanding of how one and the same organ with one and the same activity responds to tactile pressure and to vibrations of the air. It’s a weird case, but I think it’s true that the alien’s hearing is the same as his feeling, and that his hearing is relevantly like our hearing and that his feeling is relevantly like our feeling, but our hearing is not relevantly like our feeling. Moreover, we do not repeat ourselves when we say that the alien hears and when we say he feels

3. Action

Does the possibility of God’s not creating horses when in fact God created horses imply a contingency in God’s intrinsic properties? I will argue in the negative, assuming that it is possible for people like us to have libertarian free will. My account owes much to a paper by Timothy O’Connor, and maybe contributes nothing new but confusion. Start by considering how libertarian free will—which I will just call “free will”— works.

If Curley freely chooses to take the bribe, then there is some time at which it was causally possible that he not take the bribe if offered it. Moreover, there is a time after which this is no longer causally possible—the choice has been made. Let t be the earliest time with the property that after t it is no longer causally possible that Curley take the bribe. There is such a time. Before this time, Curley’s rejection of the bribe is causally open and after this time it is causally closed. Moreover, I will assume that this time t is associated with Curley’s decision to take the bribe. The decision happens at t. This is an assumption that might not hold, for it might be that at t Curley made some earlier libertarian-free decision, for example a decision to do whatever it takes to get ahead financially, which causally necessitated that he eventually make a causally determined decision to take the bribe. In that case, the bribe-taking arguably inherits its freedom from the freedom of that earlier decision. But if we are to avoid a vicious regress, we will come to some decision with the property that the decision is made precisely at a time t such that after that time some deed is causally determined as far as Curley is concerned and before it it was not. This might not in fact be the decision to accept the bribe, but for simplicity I will assume it is.

Thus, at t there was a branching. Before t it was possible for Curley still to reject the bribe and after t this was no longer possible. There are now two models of free will. On the first model, one accepted by Nuel Belnap among others, at t the branching has not yet happened: it is still causally possible for Curley to reject the bribe. It is only at t+d (for any d>0) that this is no longer possible. The time t is the last time at which matters are still open. On the second model, at t the branching has already happened: t is the first time at which matters are no longer open. I could give the argument for both cases, but that would make this talk unduly long. Instead, I will assume the first version to be correct, and for the purposes of making the talk self contained, I will say that for aught that we know, the first version is correct, and that should be all I need for my conclusions. Anyway, similar arguments apply in the second case, but are more complicated.

Thus, at t Curley is decid ing , but it is not yet true that he has decid ed . Let S be Curley’s state at t, i.e., the conjunction of all of Curley’s purely intrinsic properties at t (or, if we wish, the conjunction of all purely intrinsic properties occurrent up to and including time t). This state S occurs both in the actual world where Curley takes the bribe and in a possible world where he refuses it—I will call such a world “the alternate world”. Now, at any moment of time after t, the actual and the alternate worlds have already diverged. Curley has already done something: something he is morally responsible for. Perhaps his hand has not yet reached out for the money; maybe his enraged voice has not begun to refuse the bribe. But he is now in a state such that he is set to take or is set to refuse the bribe. (I am simplifying of course by assuming he can’t also temporize.) A deed has been done: his will has set into motion a causal chain leading up to the taking or the refusing of the bribe. Now the important thing to note is that the cause of the two different causal chains, the one in the actual world and the one in the alternate world, is the same as concerns intrinsic properties. For the cause is Curley at t in state S. Since this state contains all of Curley’s intrinsic properties at t, and these are the same in the actual and the alternate world, it follows that we have one and the same person in one and the same intrinsic state being in one world responsible for setting into motion one causal chain and in another, another.

But this seems to severely undercut the objection to divine simplicity based on the contingency of what God chooses. For we now see that one and the same person in one the same state could be in a position to initiate either of two incompatible causal chains. Moreover, note that Curley’s actual deciding was at t. During the deciding itself there was no difference in his intrinsic properties between the actual and the alternate worlds. The difference only appeared extrinsically to the decision, though as a result of the decision.

Of course the analogy is imperfect. After time t, Curley does have different intrinsic properties between the actual and the alternate worlds. But at this point he doesn’t have different intrinsic properties qua choos ing , but qua chos en : for at this time the choice has already been made. Moreover, the difference in these intrinsic properties appears mainly due to the fact that we humans execute our actions through use of our bodily and mental components, which are put in different states depending on the choice and through which we interact with the physical world. This need not apply for a being that has an efficacious will, one that directly affects external reality. To see a model of this, suppose that Cartesian dualism holds of Curley (I don’t think it holds of humans, but the notion of its holding appears perfectly coherent). Then it is conceivable at least that the way Curley’s decision worked was that at t his immaterial will did something which affected the state that his physical body was in at every time after t. Now, imagine that God smote Curley in the actual and alternate worlds by annihilating his soul at all times after t, while leaving the body intact. Then, perhaps, the body would still have been affected by the choice that the will had made at t. Moreover, at no time would Curley be in a different intrinsic state between the actual and alternate worlds, since by what we said before, he wouldn’t be in a different intrinsic state up to and including t, and after t he wouldn’t be in any intrinsic state since he wouldn’t exist—only his body would.

Thus, if libertarianism, at least in the first version on which at the decision time t the branching has not yet happened, is coherent, there is no obvious intrinsic contingency implied in God by the fact that he could have acted otherwise.

3. Belief

But in our world God believes there are horses. In another he disbelieves this. Does this not entail a difference of intrinsic properties? Here I have the least to say and what I say may be the least satisfactory. But I think we can sketch some possible models to shake our confidence that differences in content of beliefs imply intrinsic differences.

First a crazy model. This deals in a theory of mind that is almost surely false of humans, but that at least prima facie seems coherent, and so perhaps an analogue for God is coherent. Take a naïve form of Descartes’ theory on which my mind’s eye contemplates phenomena (feels, touches, etc., as it were appearing on a screen in front of my mind’s eye), and my mind’s eye is wholly distinct from the phenomena it contemplates. It is the difference in the phenomena that individuates the state of feeling hot and the state of feeling cold. One state involves my mind’s eye standing in a relation of contemplation to a feeling of heat and the other involves its standing in that relation to a feeling of cold. But now observe that the difference between these two states seems to be extrinsic to my mind’s eye: it consists in a difference between the feels, and I am not the feels. Maybe, then, God is related to the world the way the Cartesian mind’s eye is to its phenomena? Or should we insist, and if so why, that the phenomena are intrinsic properties of that mind’s eye?

Another abortive attempt. One and the same inscription can count as a statement that there are horses and as a statement that there are not horses. It all depends on the language. Thus, perhaps, one and the same intrinsic divine state counts as a believing that there are horses and as a believing that there are not horses. Unfortunately, the inscription analogy is weak. Presumably, there are intrinsic differences within the histories of the respective communities where the languages are used.

But perhaps a touch of externalism about meaning will help a little. Take a Kripkean case. On Earth we have H 2 O which we call “water”, and it is wet, relieves thirst, etc. On Twin Earth they don’t have H 2 O but do have XYZ, which they also call “water”, and it too is wet, relieves thirst, etc.: I’m going to call that liquid “shwater”. It may be that when I say “There is water in the universe” and when my twin says “There is water in the universe”, we are in one and the same intrinsic state (I’m not sure this is right, but it might be in some cases), even though the content of our assertions and beliefs is different: my assertion entails (though I may not know it) that there is H 2 O while his entails that there is XYZ. What the content of the belief or assertion is may well depend on external reality. Thus, it might likewise be that in a world with water and a world with shwater, one and the same intrinsic divine state counts as a belief, respectively, that there is water and that there is shwater. The difficulty with this as a solution to the contingency of divine beliefs problem is that it is very hard to imagine this kind of a thing being true all across the board. This sort of externalism may work for some isolated concepts, but a total externalism on which the content of all of God’s beliefs about contingent reality was entirely determined by what the actual world contained seems far-fetched. Yet it may be that this is what Thomas meant to imply when he said that God knows things by causing them. For God’s causing of the existence of a horse is, by divine simplicity, constituted as a causing of the existence of a horse by the fact that a horse in fact comes of it. If Thomas is in this way an externalist about God’s causing, then he is committed to being one about God’s believing.

None of the three attempts is wholly satisfactory. But I think at least the last one should shake any conviction that difference in content implies an intrinsic difference. And anyway, short of the beatific vision, perhaps we cannot do more to show the coherence of divine simplicity with other theological beliefs than to shake off some objections.