The Quantum Thomist

Musings about quantum physics, classical philosophy, and the connection between the two.
Riots and Racism

On Existential Intertia and Divine Conservation
Last modified on Tue Jun 23 23:18:15 2020


I was asked a short time ago to write a piece on the debate between existential inertia and divine conservation. I don't have that much to say which has not been better said by others, but I'll post a few thoughts. As with many of my posts, I am writing this primarily to get my own thoughts in order, and anything I write here should be thought of as tentative and I would welcome correction.

First of all, as always, we need some definitions. Both the theory of existential inertia and divine conservation are concerned with the ideas that things tend to persist over time. The question that divides them is why is this the case. Those who support existential inertia claim that objects have an internal intrinsic tendency to continue to exist. The analogy is with the principle of inertia discussed in classical physics. Newton's first law states that an object has the tendency to continue with constant straight-line momentum unless acted on by an external force. Existential inertia states that an object has the inherent tendency to continue to exist unless destroyed by an external agent. Divine conservation, on the other hand, states that the tendency to continue to exist, for most things, including everything made out of matter, is generated by something external to the being. It only exists because there is something outside it making it exist. If that something gets bored with the tedium of keeping things in existence, or diverts its attention for a moment, then everything it sustains will suddenly cease to exist. The key attributes of a being which are said to imply the need of an external cause to keep it in existence are contingency and compositeness.

So one view the tendency to continue existing is internal. On the other it is external. That is what the debate is over.

Now, before I consider why this debate is important, there are two further brief questions we should ask.

First question: are we setting up a false dichotomy? At first it seems like internal against external are mutually exclusive and complete, but there are a few other possibilities. The first is that the tendency to continue existing comes partly from an internal impetus and partly from an external power. This possibility doesn't interest me that much. If it is in part due to an external power, then if that power is withdrawn and nothing like it put in its place, will the object continue to exist or cease to exist? If the first, then we have collapsed into existential inertia. If the second, then we have collapsed into divine conservation. And if it is sometimes one and sometimes the other, then either there is a reason behind that choice, and we are faced with the internal and external dilemma again, or we collapse into irrationality. There is also the possibility that we live in a Heraclitian universe, in which there is no constancy at all. Everything is in flux; constantly changing and in a process of being and ceasing to be. If this were true, then neither divine conservation nor existential inertia would be correct. I don't know of any logical inconsistencies in Heraclitus' thought, but his opinion does have the strong practical objection that things certainly give the appearance of continued existence. It might of course be that they constantly destroyed and then recreated in exactly the same configuration. But, if that were so, we would be posed with a question: is the constant destruction and recreation due to an internal tendency of the object, or due to something external to it? And once we ask that question, we are back to where we started. Existential inertia or divine conservation?

All these possibilities are assuming that we have a single universe. If the Everett multiple world interpretation of quantum physics is correct, then a single particle would lead to multiple existent particles, each in its own universe, as new universes constantly branch off each other with every possible quantum event. I don't accept the multiple world interpretation, but even if we do we can still ask whether this behaviour is intrinsic to the matter or extrinsic to it. And we are left with the same choice.

So is the choice between existential inertia and divine conservation a false dichotomy? If you are really pedantic and insist on a very precise definition of existential inertia and divine conservation, then maybe. But it strikes me that all the alternatives still lead you to have to choose between something that has distinct similarities with existential inertia and something that has distinct similarities with divine conservation; and for practical purposes I don't think there is too much difference about whether we adopt the Mechanical version of existential inertia or the Heraclitian version of it. So I will leave the pedants to one side, and assume that these are the only two options in front of us.

The second question is why is it called divine conservation? Wouldn't any external cause suffice? The problem is that if you posit an external cause of continuing existence, then eventually you get back to God. The argument is straight-forward, and will be familiar. If a being is held in existence by the act of an external cause, then that external cause must also continue to exist, because nothing can act unless it exists. That cause in turn must either exist because of some internal tendency to exist, or because of some external cause. And if it is an external cause, then we just repeat the question again. This sequence cannot continue to infinity, because it is an essentially ordered series. If there was no termination of the series, then we would just have a long chain of things which which themselves cannot generate existence but which nonetheless exist. So the sequence must terminate with something whose existence is inherent to its nature, or more than one such thing. We then ask what the attributes of such a being would be, and we find that it must be unchanging, immaterial, single, intellectual, simple, and so on, and after a bit of work recover all the usual divine attributes. So those who advocate an external cause of continued existence do not claim that there is nothing out there that does not continue to exist due its inherent nature rather than something external to it. But they claim that there is, and can be, only one such thing, namely God. So ultimately the conserving is done by God, albeit possibly through a number of intermediaries, and that is why it is called divine conservation.

So why is this important? The most obvious place is in arguments over the existence of God. If divine conservation is correct, then God exists. One doesn't have to invoke divine conservation to have a cosmological argument. I personally usually fall back on arguments related to the tendency towards a state of equilibrium in a complex system, which can be shown from basic physical principles. And I think that my argument works, and it is more accessible to scientists who don't want to get into a long debate about whether or not there is divine conservation. But if divine conservation is true, then the rest of the cosmological argument drops out immediately. Of course, existential inertia isn't in contradiction to the existence of God. But a pure, mechanical vision of existential inertia does lead us towards a more deist rather than theist outlook. Atheism and deism, if they are to be internally self consistent, must assume existential inertia. So this issue is at the heart of the discussion between theism and atheism. Of course, one might have other good reasons for accepting theism, which would then provide good evidence that divine conservation is correct. Or one might have other good reasons for accepting atheism, which would imply that existential inertia is correct. But my focus here will be on whether there are any good direct arguments for one or other of the beliefs.

A second reason that this debate is important is that Roman Catholic dogma asserts divine conservation. (I am using Edward Feser as my source here; if anyone disagrees with this statement then please direct your complaints to him.) This might only seem like a small matter, but it is a dogma that has been affirmed by a council of the Church. That means that if you prove it to be false, you also call into doubt the infallibility of the magisterium. If it could be wrong on one point, it could be wrong on any point. To the Roman Catholic (as I understand it as an outsider), the authority of the Church is a key part of the basis underlying everything else. Prove existential inertia to be true, and you banish popery and all that goes with it into oblivion.

The book of wisdom puts it clearly,

How would anything have endured if you had not willed it?

In the New Testament, we read

He is the radiance of the glory of God and the exact imprint of his nature, and he upholds the universe by the word of his power.

And he is before all things, and in him all things hold together.

The doctrine of divine conservation has been upheld by numerous doctors of the Church, including the big guns of Augustine and Aquinas, and was affirmed by the council of Trent.

Now, I am a protestant rather than a Roman Catholic (much as I respect many aspects of Roman Catholic theology). As such, I believe that the Council of Trent was mistaken about a great many things. To the protestant, the ultimate authority is Christ alone, and that authority only extends to the prophets who wrote of Him, and the apostles who wrote in His name. Subsequent generations of Christians mixed truth and error; considerably more truth than error, but everything is in question unless backed up by clear Biblical testimony, or what can be logically deduced from clear Biblical testimony. The Old Testament should be restricted to just the Hebrew canon which Jesus affirmed, and the book of wisdom ought to be excluded. Augustine and Aquinas were great authorities, but still human authorities: they weren't infallible. And of the Biblical texts cited, only the deutero-canonical one is clear-cut in supporting divine conservation: the New Testament ones have some interpretive room. So proving existential inertia wouldn't be enough to cast classical evangelicalism into the pit of oblivion to the same extent as it does for Roman Catholicism.

But it would still make us classical evangelicals uncomfortable. While the Church Fathers such as Augustine and the texts of the apocrypha lack Biblical authority, they still command greater authority than myself or the Bishops and theologians of this age. You need very good reasons to go against them. And while the New Testament texts might not imply the strictest form of divine conservation, one would have to stretch them a long way to make them agree with existential inertia, especially the simplest mechanistic variant of that doctrine. So, while my creed might not depend on divine conservation, it does strongly prefer it to the alternative. And the voice of the Church needs to be listened to, especially when the doctrine in question can be shown to go back to the earliest days.

So that is what is at stake: orthodox Christianity. Perhaps theological liberals and the neo-orthodox protestants could survive this battle (although they would lose others); but for those of us who never felt tempted to jump on the enlightenment bandwagon (with all its irrationalities), this is a crucial debate. If divine conservation is true, then we are right, and, with victory complete, we can dissolve our uncomfortable alliance against the secularists, and return to our traditional pastimes of burning each other at the stake. If it is false, then we would be wrong, and would deserve the same lack of intellectual respect that is traditionally rendered towards circus fortune tellers and Episcopalians.

So, yes, this discussion is more important than it might at first seem.

What can physics say?

So, we have two options. As a physicist, I am interested in the theoretical basis only inasmuch as it leads to practical consequences. If we have two different theories, then we search for some experiment where the two theories make different predictions, perform that experiment, and thus select one over the other. If there is no experiment that can distinguish between them (either because we can't achieve the required precision, or because they give identical predictions in every circumstance), then we keep an open mind. We say that we simply don't have evidence to judge between the two options. Or maybe someone will write a paper to show that the two theories are formally equivalent: both theories say the same thing, just expressed in a different notation. Of course, in practice, matters are never this simple. There might be seemingly conflicting experimental results. There is the matter of interpreting experiment and accounting for all the systematic errors. Drawing out predictions from theories is rarely easy, and can often rely on additional assumptions. There is often some flexibility in theories allowing for a range of predictions. And so on. But despite all these caveats, the underlying principle remains sound.

Just as for physical theories, the same principle would apply to metaphysical ideas. Metaphysics is the ground of theoretical physics; just as theoretical physics underlies practical physics. So we ask how the metaphysical concept would constrain physical theories. And then we move from theory to experiment, and search for practical differences between the two approaches.

But in this case, we have a problem.

Suppose, in the first instance, that it is found that the fundamental particles of physics are described as being as indestructible by theory. This is the case in Newtonian physics. They always continue from one moment to another. This is obviously consistent with existential inertia, which states that beings have the inherent tendency to continue in existence, unless acted on by an outside force. In this case, there would be no need to call on an outside force, and existential inertia would clearly be compatible with the observations as explained by the theory. But, on the other hand, the circumstance would also be consistent with divine conservation. God is, after all, timeless and immutable in His purposes. He could choose to annihilate any particular lump of matter, or create something new. But He doesn't have to. He could just choose to always preserve matter in existence. Obviously, this creates various deep theological implications, but theism is big enough to handle that.

On the other hand, if, as quantum physics suggests, matter is not indestructible, but one particle can be annihilated and another created from its ashes, then this is clearly compatible with divine conservation. We would have to postulate a God who sometimes chooses to maintain matter in its current state, and sometimes chooses to destroy it and create something new. Again, this demands a God with a free will, who is not constrained to act in exactly the same way in every identical circumstance. We would have to choose a different model of theism than if Newtonian physics were correct, but it would still be theism. But then, the advocate of existential inertia would also be content. Existential inertia (if the analogy with Newton's first law holds) states that things inherently continue in existence unless acted on by an external force. In this universe, we would merely have external forces capable of transforming matter. This obviously has implications for which particular model of existential inertia we choose; but it would still be existential inertia.

So it might seem that physics has nothing to contribute to this debate. Both sides can be shaped to make identical predictions about the physical world. True, the doctrine of existential inertia is more comfortable in a Newtonian world, and the doctrine of divine conservation more comfortable in a quantum world, but ultimately it looks like both ideas are consistent with all the possible physical theories. After all, physics describes what happens, but has less to say on why it happens that way.

But I'm not so sure that we can dismiss the science that quickly.

Where existential inertia might have problems is if there is the spontaneous annihilation and corruption of particles. For example, if we have two particles collide, and as a result of that collision they get annihilated and something else created in their place, then that's easy to explain. The outside force that causes the destruction of one particle is the other one. But we could also have events where there is a change in state without any collision to trigger it. An electron emitting a photon, for example. Or a photon decaying into an electron/positron pair. In this case there is no external physical cause behind the change. It can't be the original particle itself which leads to this decay, because under existential inertia particles only have the inherent tendency to continue to exist. If proponents of existential inertia were to propose that a particle has more than one inherent tendency, either the tendency to exist or to cease to exist, then the question becomes why it selects one over the other at any given moment in time. This reason cannot be internal to the particle; since then one or other of the options would be forced. Neither could it be external to the particle without denying existential inertia. The only option remaining is that there is no reason, and that the universe is fundamentally irrational; an proposition that I think all scientists would find objectionable. I think the defender of existential inertia has a problem here. Perhaps not an insurmountable problem, though, since I can think of various approaches they might take to avoid it.

Of these workarounds, only the third strikes me as reasonable. You could, adopting a field ontology, suppose that all electrons in the universe are simply different states of the same underlying thing. And maybe you could suppose some unified theory, where all the different Fermions get merged together into this great unified blob. But Bosons and Fermions are fundamentally different. I can't see how you can have a unified Boson/Fermion field which would allow you to take this path out of the problem. For the second option, all known physical interactions involve the transference of energy and momentum. The fundamental theory would have to have interactions which don't do this, where a particle can interact with others without transferring energy. But then it would still reduce to (either by taking a particular limit or some sort of averaging process, which is how we get from one layer of physics to the next) a theory in which every interaction has to involve the transference of energy and momentum. Again, I find this difficult to believe; I also don't like speculating about unknown physical theories to try to solve a problem with current theories which can be solved more simply by other means. And finally, if you posit irrationalities in one aspect of physics, you still have to explain why the universe is otherwise rational. A wholly irrational universe, where there is no logical foundation or cause and effect, I can imagine. A wholly rational universe I can also understand. But something that mixes the two demands an explanation of how we determine which phenomena are rational and which irrational.

The third of these possibilities, which posits an external, non-physical cause for the spontaneous decays, strikes me as being functionally equivalent to divine conservation. There are differences, of course, at the deepest level. In divine conservation, God directly chooses to preserve the substance from moment to moment. In this version of existential inertia, God only does so indirectly, as a consequence of his decision to not institute some spontaneous decay at that moment in time. For all practical purposes, though, I don't think that these two theories can be distinguished, and arguments which use divine conservation as a premise will have equivalent arguments based on this form of existential inertia. So this isn't an option for the committed atheist.

I should also mention the big bang here. Is this relevant to the question? It does seem to indicate creation of the universe out of nothing. This is the opposite question to existential inertia. Existential inertia states that things have the inherent tendency to continue to exist; while the big bang seems to suggest that this tendency didn't stretch forever backwards in time. Why should we then expect it to stretch forever forwards in time? There are, of course, various which suppose something before the big bang out of which our own space time emerged (for example bubble universes). But in this case, there is again a spontaneous change. Something came into existence when it wasn't previously existing, or there was a change of state. But models of the big bang are still very uncertain and rather messy; and existential inertia doesn't preclude things from coming into or out of existence; only that they need an external cause to do so.

So in the Newtonian world in which existential inertia was first popularised and many philosophers seem to live, physics can't be used to distinguish between existential inertia and divine conservation. However, if you choose divine conservation, it seems to put limits on God's freedom to act. But that world is irrelevant, since its not the one we live in. In a quantum world, then existential inertia seems to a have problem, while divine conservation is fully consistent with it. One cannot postulate that things have an inherent tendency to continue to exist in the same state when they don't always continue to exist in the same state, even when there is no physical interaction. There are, however, various ways in which the advocate of existential inertia might try to avoid this. The only one that seems plausible to me (that there is an external non-physical cause for the change) is functionally equivalent to divine conservation. But maybe there is another way around this I didn't think of, or one of options I rejected is stronger than I believe it to be.

The case for divine conservation

So what is the philosophical argument for divine conservation? One argument is that most substances we see around only exist contingently. That is to say that they are the union between their essence (which by itself doesn't imply existence) and an act of existence.

God is obviously seen as an exception to this; God is a being that exists essentially. This isn't a cop out: we infer from the presence of contingent substances that there must also be something that exists essentially, and we define this to be God. And if someone quibbles that this is committing the fallacy of equivocation -- we are using the word God in a different sense than is customarily used in the monotheistic religions -- we would go on to show that the notion of something that exists essentially, plus the argument linking it to contingent beings, implies all the usual divine attributes. But that has been dealt with elsewhere, both by myself and by others more qualified than I.

If things only exist contingently, and they do in fact exist, then there must be a reason why they exist. (That's ultimately the definition of contingent: the truth of a statement, such as X exists, is conditional on some other statement being true.) This reason cannot be internal to them -- they cause themselves to exist -- because nothing can be its own cause. Therefore it must be something external to them.

As I read Feser's account in his essay on existential inertia, his main argument was that the composite nature of the being is also crucial to the argument for divine conservation (everything composite is dependent on its parts being united together, and is therefore contingent). While it is quite possible that I have misunderstood his argument, it strikes me that this is not quite all that needs to be said. He is quite correct to say that the creation of something composite (for example a union of form and matter) requires something outside itself to bring it into being. Form cannot by itself initiate the union with matter; matter by itself cannot take on a particular form. If it were true that either part could do that by itself, then one would not be able to distinguish the parts. Something else must bind them together. His argument was that neither form alone nor matter alone are capable of generating existence. This is quite correct. So if a being is the union of form and matter, then there is nothing in it which can explain its existence. The union must require something external to it to bring it about; and (and this next part of Feser's claim is where it gets controversial) to keep it in existence. But we are not discussing the creation of a being, but its continued persistence. A composite being can have properties that its parts lack. For example, water has the property of being a liquid at room temperature and standard pressure, while its parts, hydrogen and oxygen, are gases. Nothing can give what it lacks; and neither form or matter alone have the ability to provide existence. But the union between form and matter does possess the attribute of existence, and therefore could perhaps provide it to something else. Thus it might be that existential inertia arises from neither part of the substance, but from the bond that unites them, or, more specifically, the union between the parts and the bond.

We need to show that the reason for the being's existence can't solely be the same being, X(t) in the same state but at the previous moment in time. It is not a matter of it causing itself -- that would be X(t) causing X(t), which is clear nonsense. What we are discussing is the possibility that X(t) causes X(t + δ t). I'm not sure that the presentist needs worry about this objection (since only things at the current instant in time exist), and since Feser is a presentist perhaps that is why he doesn't discuss it. But those of us who aren't presentists need to worry. So I will give it a go; if anyone can improve on this argument I would be delighted to hear it. I will assume that X doesn't interact with any other physical particles between the time of its creation and time t. If existential inertia is correct, then there must be for at least some beings some time t for which this applies.

The first question is how we define persistence in time. There are several ideas here consistent with the four dimensional view.

This causal model of persistence does not by itself distinguish between existential inertia and divine conservation. The tendency towards the end still has to be actualised. If the actualisation of the tendency to produce an effect identical to X is even partially actualised by something external to the being, then we are back at divine conservation. If it is wholly internal to the being, then we have existential inertia.

But the problem is that X doesn't just have a single inherent tendency to continue as it is. It can change. This is guaranteed by its composite and contingent nature. Thus it has several inherent tendencies. This is a problem if its ability to actualise the tendency is solely internal to the particle. Which option will it choose? There is no reason why it should prefer one over the other. If we are discussing an external agent as the actualisation of the change, especially if that external agent is God, then it has the ability to choose one option over another. But, if the being actualises its own tendency, then it can only ever choose one of them (in the absence of any interaction with an external force or particle). We are supposing that X(t) and X(t + δ t) are identical in every relevant way except that they are at different moments in time. That means that whatever it is about X(t) that leads it to become X(t + δ t) over any other options will also be present in X(t + δ t). The being will never change (or constantly change in the same way), until it interacts with something external to it. And when it does interact with something external to it, assuming that that other being is another physical particle subject to the same considerations, then whatever results from their interaction will just depend on the precise circumstances of their collision. There would be only be one possible outcome of the interaction.

What if particles were born with an internal clock (unknown to current physical theory, but maybe a hidden parameter accessible to a future theory) which gradually ticks down until it is time for the particle to decay? Most of the time the particle moves from one state to another in a predictable way, which is allowed according to the argument above. But then we have a problem: is the initial value of the clock random, or is it caused by the particular conjunction of events that led to the creation of the particle? If it is determined by the conjunction that created the particle, then we have either a deterministic physics, or some there is some external non-physical cause (which would again lead to God, and ultimately a form of divine conservation) which sets the clock. If it is random, with no reason why it was set that way, then we are left with an irrational universe again. And whatever model we adopt for this clock needs to be made consistent with quantum physics, which will not be easy (I haven't any proof of this, but I suspect that there would be a Bell-like theorem coming into play). Finally, if a particle does have an internal clock counting down to when it decays, that does seem to contradict the notion that beings have the inherent tendency to persist in existence unless acted on by an external force.

This is as far as I have been able to go. I haven't been able to come up with a purely philosophical argument that rules out existential inertia. But what I think I have shown (unless there is something I have missed) is that existential inertia specifically requires that the universe is:

Even then it would still not be inconsistent with divine conservation. But the universe we live in is not deterministic. (The only Bohmian interpretations of QFT I know of have to still introduce spontaneous jumps for each particle creation or annihilation event; existential inertia assumes a single universe which rules out the Everett multi-world interpretation.) Thus, given my premises, existential inertia is false.

What are these premises? Firstly, I accept that there is spontaneous corruption of substances. Obviously, in a mechanical world view, this might be explained for complex substances while being consistent with existential inertia. They corrupt because their parts are rearranged -- and it is those parts which are subject to existential inertia. However, mechanistic world view is false. Complex objects are not merely the sum of their parts. And even fundamental particles can spontaneously decay. So here I have clear experimental evidence on my side, and, where available, that is the final word in any dispute. Secondly, I am presupposing a hylomorphic view of matter. I have defended that elsewhere, and do not want to reiterate that argument again. Thirdly, I have supposed that material particles are contingent rather than necessary beings (using my own definitions of those terms). Given that necessity implies immutability and indestructibility, neither of which apply to material particles, this seems clear enough.

The case for existential inertia

So what of the case for existential inertia? The first thing we must bear in mind is that there is no experimental test which can prove existential inertia over divine conservation. (However, existential inertia does imply that things, once created, will not cease to exist unless acted on by an external force; so the combination of existential inertia and the idea that everything in existence can be captured by a scientific investigation can be falsified through experiment.) Therefore any argument for existential inertia can only be philosophical, not scientific. However, we should also note that atheism and deism presuppose existential inertia. Thus if there was a good argument for atheism, then that would imply that existential inertia is correct. However, such an approach is circular: most atheists accept atheism because of a perceived lack of evidence for theism; but if existential inertia is false then there is good evidence for theism. This discussion should determine whether we become an atheist or deist on one hand, or a theist on the other; not the other way round.

The strongest modern argument for existential inertia is reputed to be that by Beaudoin, which unfortunately I don't have access to. Professor Feser responds to a number of arguments in support of existential inertia in his essay, and the topic is also discussed in an article by Paul Aldi, who concludes that the question is undecided. These are some of the arguments I have seen presented for existential inertia. If there is a good one I have missed, then please let me know.

  1. Existential inertia is a simpler doctrine. It is more simpler to believe that complex beings disintegrate simply when their parts fly apart. They are only superficially contingent, and not the radical contingency that would disprove existential inertia. This objection relies on a disproved mechanical view of matter, and is therefore false.
  2. No form of causation is in general required to ensure persistence in being. This is begging the question.
  3. I agree that some explanation is required to explain the persistence of contingent beings, but existential inertia is sufficient to explain it. Existential inertia is no more an incoherent claim than the idea that God endures for ever. According to Feser, this is Beaudoin's main argument. The analogy with God is clearly false, since the argument for divine conservation rests on being's contingency and compositeness; while God is taken to be necessary and simple. The arguments clearly don't apply to God. (Indeed, this serves as an argument for the simplicity of God; if God is defined as the termination of the chain of explanation, and every composite being needs an explanation outside itself, then God must be simple.) Feser criticises Beaudoin's argument that his vision of existential inertia offers no explanation for persistence. He has just observed persistence, and slapped a name on it, and no more than that. That is no different from observing that things fall down, say "that's because of gravity," but make no attempt to explain what gravity is and why it is aside from it being the tendency of things to fall down. Having not read Beaudoin's paper, I can't judge whether this criticism is fair. But if Feser's characterisation of his argument is correct, then the criticism is reasonable.
  4. The conservation of energy entails existential inertia. Firstly, this statement is wrong: the conservation of energy ensures that something material persists over time, but not that substances persist over time, which is the question of interest. One type of particle can decay into another. Secondly, the conservation of energy is a description, not an explanation. It tells us that something called energy -- which is a label used to distinguish states, not a physical being in itself -- has the same value over time. It does not explain why that is the case: both existential inertia and divine conservation are consistent with the fact.
  5. The second law of thermodynamics says that the entropy of an isolated system never decreases. (This is taken from Aldi's article.) I struggle to see what the objection is here. The question is why substances persist over time. Entropy is not a substance, so its persistence is an irrelevance.
  6. Ceasing to exist is a change. Every change requires a cause. Therefore ceasing to exist requires a cause. Nothing can cause itself to cease to exist. Therefore nothing will cease to exist unless something else causes it. This argument relies on event causality, which in terms of the physical universe alone is dubious (as opposed to substance causality, which is secure). Equally, in divine conservation there is a cause for something ceasing to exist, namely God. The difference between divine conservation and existential inertia is not over whether ceasing to exist requires a cause -- both of them agree on that (existential inertia demands that it does, usually another physical object or perhaps God; divine conservation would say that the cause is God, perhaps alongside another physical being). The question is whether persistence requires an external cause.
  7. 1) There is no distinction between a region of space-time and what is in it. 2) So there is no such thing as an object’s vanishing from its location. 3) Ceasing to exist would be vanishing from a location. 4) Nothing can cease to exist. 1) is false.


On summary, I would say that the balance of the evidence supports divine conservation over existential inertia. I am not quite sure that the medieval argument for divine conservation (as articulated by Professor Feser) is completely secure, unless one also presupposes presentism. However, I have tried to extend that argument into a four dimensional view of time. If my analysis was correct (and I make no firm claims that it is), if the advocate of existential inertia took this route, it would lead him down a road towards a deterministic universe; with all alternatives to that path ultimately leading back to divine conservation, or something which for all practical purposes can be considered as equivalent to it. Since the universe is not deterministic, I think that the advocate of existential inertia has a problem. Central to this problem is the fact of spontaneous decay.

But, as mentioned, I am no expert on this topic, so I would welcome corrections and criticism.

Is God a failed Hypothesis? Part 1: Introduction

Reader Comments:

1. John Not Real Name
Posted at 10:35:54 Friday June 26 2020

Bohmian Mechanics?

Can David Bohm be considered a proponent of a more Classical approach to Quantum Mechanics? Non-locality and Essences not deconstructed to the sum of it's parts are there so any bite? Thank You for your consideration.

2. Nigel Cundy
Posted at 21:35:23 Sunday June 28 2020

Bohmian mechanics

Bohemian mechanics is certainly closer to the classical view than most other interpretations of QM (the Everett Multi-world interpretation is also vaguely classical). However, it is difficult to reconcile it to relativistic field theory. There have been a few attempts to do so, but none of them are particularly convincing.

3. Matthew
Posted at 00:20:00 Wednesday July 1 2020

Your resident pilot-wave proponent strikes again

I'll grant you that Bohmian mechanics is difficult to reconcile to relativistic field theory, though I think it can be done. (I've constructed toy models in finite 1D and 2D universes with a momentum cutoff - the argument is that either it is somehow possible to take the limit of infinite field modes, or that it is able to reproduce all empirical phenomenon with a high enough cutoff.)

The claim that none of the attempts is particularly convincing is a subjective one, however. :)

4. Nigel Cundy
Posted at 11:58:39 Sunday July 5 2020

Bohmian mechanics

Thanks Matthew for your comment (perhaps I should have referenced your views and earlier comments in my text). I stand by my claim that I haven't seen a convincing Bohmian interpretation of QFT that doesn't still rely on spontaneous jumps from one configuration of fixed particle to another (and thanks for pointing out that paper to me), which is all I need for the argument above. But obviously, if you have an alternative, then it would be good to hear it (even though it would be a bit annoying, because I would have to come up with another version of the argument in this post).

5. Dominik Kowalski
Posted at 08:02:36 Monday July 6 2020

Physical Simples

Hello Dr. Cundy!

As the premises for the cosmological arguments become weaker, I see that the existence of fundamental “physical simples“ proposed as naturalistic candidates for a necessary being (if we don't want to follow Jonathan Schaffer and propose the universe as one whole necessary substance it seems like its the only candidate). Leaving out now the issue of being composites of essence and existence and the absurdity of getting quantifiable properties as absolutely necessary facts (not even speaking of that this will probably lead to Spinozism), I would like to know if physics itself has anything to say on the issue? Would strings be such simples? Does its proposal presuppose a mechanistic worldview or could they also be on a more (though not fullfleshed) aristotelian ontology? If physicists like Paul Davies or Stephen Barr write that quantum mechanics refutes materialism, do the conclusion they draw affect the idea of physical simples at all?

That are all the questions to that topic I can come up with at the moment, but everything that could be added would be in the same ballpark. Thank you for your posts, they are highly informative.

6. Dominik Kowalski
Posted at 08:22:36 Monday July 6 2020

Addendum: Is the debate over “Atomism vs Gunk“ relevant to that topic?

7. Nigel Cundy
Posted at 21:01:20 Monday July 6 2020

Physical Simples

Dear Dominik,

Thanks for your comment.

I personally don't like treating the universe as the necessary being for the simple reason that the universe isn't a being.

Secondly, you ask whether a physical substance can be the necessary being. Regardless of the composition between form and matter, I think the answer here again is no. All physical beings have the capacity for change. You mention strings. I'm personally not a big fan of string theory. While there is some beautiful mathematics there, there is too much there which strikes me as contrived: it is difficult to make predictions from it; difficult to reach the standard model, and its dependence on applying the result that the Reinmann zeta function of -1 is -1/12. (I understand the mathematics, but it relies on a particular form of analytic continuation which I am not sure is applicable to the physical case.) The failure to find supersymmetry at the LHC is also a blow against string theory. I could of course, be wrong here; but we should pay more attention to string theory's alternatives.

But even strings have excited states. That means that a string has more than one potentia: it is actually in this state, but could be in that state. However, cosmological argument must terminate with something unchangeable. Otherwise we end up with the question of why that particular state happened to be first (the "What caused God?" argument, which fails if the termination of the series is necessary and unchangeable, but needs to be answered otherwise).

And this is the ultimate reason why the termination of the cosmological argument can't be something physical. We can deduce the attributes of that being (see the first part of the Summa Theologica, or Feser's five proofs, Augros' book, or almost any classical theist text which gives anything more than a superficial rendering of the argument). Whatever the first cause is, it can't fit any physical or material substance.

8. Matthew
Posted at 15:37:22 Tuesday July 7 2020

Pilot-wave theory

An alternative to the quantum jump model (a pilot wave theory that uses particle positions as the primitive ontology) would be one that has a field configuration as the primitive ontology, like Bohm's pilot-wave model of the electromagnetic field (this was the first such model) or others that have been put forward since then (Struyve's review article "Pilot-wave approaches to quantum field theory" reviews a number of them; Holland's book "The Quantum Theory of Motion" contains a section outlining the approach that I currently think shows the most promise). These models postulate a continuously-evolving field configuration as the fundamental beable, rather than particle trajectories with indeterministic annihilation and creation events. On my website (here: or here: I have a couple of models showing what those could look like.

Of course, this doesn't necessarily mean you need to rework your argument in this post, because the fundamental ontology postulated by a physical theory might not be all there is to the physical world. For example, the field configuration might not include distinct particles, but the quantum state guiding the field configuration in these models does have discrete excitations. A hylemorphic view could see the quantum state as a partial representation of the forms of things that actually exist above the level of the fundamental field, including particles, atoms, molecules, or what have you. In which case there is still particle creation and annihilation, as well as the generation and corruption of higher-order substances made up of particles.

I will admit that I also am not entirely satisfied by the extant models, mainly because the guidance equations for the fermionic field modes are horrendously complicated, and only get worse in the limit of infinite field modes. Nevertheless, I think there are very good reasons (basically, stemming from scientific realism and the need to resolve the measurement problem and the lack of a clear ontology for quantum theory) for thinking that something like pilot-wave theory is correct.

9. Priscilla
Posted at 17:52:54 Friday July 10 2020

Hello Mr Cundy, this isn't related, but mind if I ask your opinion on Top Down-causation?

10. Nigel Cundy
Posted at 16:37:54 Sunday July 12 2020

Pilot wave theory

Matthew, thanks for the links you sent me. They are helpful. I've glanced through your own work, and have a few questions about it, but it is a bit too much to take in without doing a proper line by line reading, so (assuming I find time to do that during the week) I'll reserve my main comments until then. Two questions to get started: Why did you propose a 2+1 dimensional model of QED rather than a 3+1 dimensional model (which would be easier to compare against experiment). It doesn't strike me that a 3+1 dimensional model would be that much more complex. Secondly, I am a bit nervous about your Lagrangian, and in particular your mass term mixing particles and anti-particles. That's not part of the usual standard model.

I'm afraid I can't comment on Holland's book, since I don't have access to it (and its price is beyond my book budget).

Struyve's review article, to my reading, confirms my feeling. None of the models it considers actually work, or at least they all need more work. The statement in section 3.1, "The theories that we will consider are not Lorentz invariant at the fundamental level," is particularly troubling for me. Granted it argues that the appearance of Lorentz invariance will re-emerge when you calculate variables. But then, if Lorentz invariance is not present at the fundamental level, why choose a model which implies it at the level of observations? \bar{psi} \Lamba_\mu (\partial^\mu - ieA^\mu) psi, where \Lambda_\mu is some fixed vector is a perfectly good Lagrangian density, which other than breaking Lorentz symmetry leads to a self consistent QFT. If Lorentz symmetry is not fundamental, then why isn't that Lagrangian, or the standard non-relativistic Lagrangian, the true model of nature?

Bohm's field-theoretic approach is not applicable to Fermions, so that can't be right.

The Euler angle approach of Holland is difficult to accept because it can't lead to empirical predictions, or express key variables in a location basis. The lattice alternative also seems troubling. One of the difficulties in Lattice Gauge Field theory is defining the continuum limit (in which Lorentz invariance re-emerges). In practice, this is performed by considering a renormalisation group flow towards a trivial ultra violet fixed points (i.e. the renormalisation group transformation that reduces the length scale leaves the parameters of the system unchanged at a zero coupling). This is actually problematic in pure QED, since there is no such trivial fixed point in that theory; one has to combine QED with a strong interaction. A key premise of the argument to define the continuum limit is that the underlying theory should be local (defined in a particular way). The violation of locality in these theories would seem to me to imply that we can't use a lattice formulation (either in physical or momentum space).

The Grassmann field approach leaves an undefined measure.

Then we have the particle ontologies. Bell's approach has no Bosons. Duerr's approach requires stochastic jumps, which leaves us in the same position as other local interpretations of QFT. The Dirac sea approach requires the conservation of Fermion number, which is violated in the standard model. (I also can't see how it can cope with flavour changing weak interactions; but I haven't looked into that much depth.

In other words, I stand by my claim that none of the Pilot wave approaches to QFT have been shown to be compatible with the standard model. The problem is that advocates for these models need to demonstrate that their models can lead to empirical predictions which are equal to (or better than) those of the standard model. If you can do that, then great. If not, you still have work to do.

11. Nigel Cundy
Posted at 16:59:55 Sunday July 12 2020

Top down causation


Thanks for your question.

I understand top-down causation to mean an analysis where you start with the macroscopic properties of something, and work from that down to the microscopic properties. So the microscopic elements are in some way orientated towards the needs of the macroscopic structure. Bottom up is the opposite: you start in terms of the most fundamental microscopic particles, and from knowledge of their properties work your way up to uncover the properties of microscopic systems.

I'm a particle physicist by training, so I live in a world of quarks and gluons. This gives me a natural prejudice towards bottom-up causation. I look at quarks and gluons, and then derive from that their bound states (pions, protons, neutrons). Then the nuclear physicist will take what I finish it, and use that to build up a model of the nucleus, and from that we go onto the atom, and so on. So I do think that bottom-up approach is sufficient to explain physics.

However, that doesn't mean that the top-down approach is also wrong. Obviously, historically, we have started from the top and gradually worked our way down. And there is a sense in which the higher layers are present inside the lower layers, in that (for example) quarks have the tendency to form the bound state of the proton or neutron. So one could say (in a certain manner of speaking, not restricting ourselves to the modern definition of the word 'purpose' but also allowing ourselves natural purposes) that the purpose of the quarks is to form the proton. The proton is also a substance in its own right, and not reducible to merely its parts, although its properties and nature can be deduced from knowledge of its parts.

So I don't personally have much of a view about top down causation. It is not an approach that I have used in my own scientific work. My philosophical work suggests that is there in the background. If I had to say something, it would be that there is room for both the top down and bottom up approaches. When both fully worked out, they would be functionally equivalent to each other (i.e. ultimately say the same things about nature, and make the same predictions), although looking at things from one angle might give us insights which are less obvious when looking at things the other way.

12. Matthew
Posted at 17:09:17 Monday July 13 2020

Models of pilot-wave QFT

Hi Dr. Cundy,

I greatly appreciate you taking the time to look at what I've written up on these pilot-wave QFT models. These were never really intended to be more than toy models - I chose a lower dimensional space (initially 1+1, and then 2+1) because it would be easier to create an actual, visualizable simulation of such a model. It's more of a proof-of-concept than anything else. You are right that it should be possible to extend the 2+1 model to a 3+1 model, but handling the extra modes of the spinor and vector fields that are introduced in that move is more than I had time to deal with. (I'm just layman who plays around with these things in my spare time, not an actual physicist!)

The split between particle and anti-particle terms is, essentially, just a quirky way of writing the usual QED Lagrangian - it is just collecting the positive frequency modes under the label "particle" and the negative frequency modes under the label "anti-particle". In 3+1 dimensions there would be four sub-fields: spin-up and spin-down for the "particle" and "anti-particle", respective. See Sebens, "Putting Positrons into Classical Dirac Field Theory" ( (Which, despite the title, discusses quantization of the Dirac field as well.)

I understand that "this theory is not Lorentz-invariant at a fundamental level" makes you, and most physicists, nervous! I simply don't believe that it should. The reason that we have for believing in Lorentz-invariance comes down to the empirical evidence, and a pilot-wave theory can reproduce that (or so I claim). The Standard Model QFT is already non-local: it violates Bell's locality criterion (and that is true without having to use any probability axioms to prove the full Bell's theorem). Pilot-wave theories only make that non-locality more explicit, because they specify a precise ontology in space-time (the local beables, using Bell's terminology) which orthodox QM fails to do. I consider a precise specification of the ontology to be a key requirement of scientific realism. If the only models that satisfy that requirment are non-local, and Bell's theorem is a strong argument that this is the case, so much the worse for fundamental Lorentz-invariance or locality. (I hope you'll forgive me for saying I remain intrigued but unpersuaded by your rejection of the standard probability axioms.)

Why choose a Lorentz-invariant Lagrangian to quantize, if Lorentz-invariance is not fundamental? Because quantizing a Lorentz-invariant Lagrangian produces Lorentz-invariance at the level of observations if not at the fundamental level of ontology, which matches the empirical data! Why is the quantization of a Lorentz-invariant Lagrangian the true model of nature, rather than something else? One could also ask why a quantum theory of any kind is the true model of nature, rather than some classical theory. At some point, you have to say "that's just what God decided". Newton recognized that the observational evidence supported Galilean-invariance but nonetheless saw no problem with postulating an absolute space. This is similar.

Holland neglected to flesh out his Euler angle approach with an appropriate ontology for the local beables, but it is possible to do so, and that's the approach I took in my 2+1 QED toy model. It is similar to what Struyve proposes on page 13 of his "A minimalist pilot-wave model for quantum electrodynamics" (, only it depends on the configuration for the fermionic field modes (the Euler angles) in addition to the bosonic field configuration. So when properly amended, Holland's model can express the key variables in the location basis. Your concern about the discretization of the momentum space in these approaches may or may not be justified; I am not sure. When you say "A key premise of the argument to define the continuum limit is that the underlying theory should be local (defined in a particular way)"; it depends on just what that locality amounts to. In some sense, the "underlying theory" of these pilot-wave models is local, i.e., they are quantizations of a local classical field theory. And in some sense, the Standard Model QFT is non-local, because it violates Bell's locality criterion.

(I might also note that if the universe really were spatially finite, then the momentum space for a field theory like this would have to be discretized, whether there were an infinite number of field modes or no.)

But I completely agree with you that more work needs to be done to bring these pilot-wave theories up to the level of orhtodox QFT. I just think that work is worth persuing by the physics community, whereas too many physicists, in my opinion, unjustifiably see it as worthless.

14. Mark
Posted at 10:38:27 Sunday October 18 2020

An New Article on Existential Inertia

Hello Dr.Cundy, thank you very much for all your works, they are very enlightening and helpful for me a philosophy student who loves Aquinas who also tries to understand contemporary physics. I love what you said about existential inertia, and here is a link to perhaps the latest article on this topic. Could you comment on this paper? Thank you very much.

15. Augstine Fung
Posted at 00:59:50 Friday January 15 2021

This blog is exactly what I have been looking for. I was reading Ed Feser's Five Proofs of God, and the only part I do not understand about the Aristotelian proof is why the potential of existence of things needs to be actualized. In other words, why can't this coffee I am drinking exists just because a sequence of events since the big bang had lead to the quarks organized into this coffee I am drinking (hence Deism). Now I understand I had preassumed existential inertia. I might have to read this post multiple times to understand your argument. My institute actually has access to the Beaudoin paper you referred to. Maybe I could send it to you?

16. The Local Papist
Posted at 03:11:56 Sunday January 17 2021

I think it is very strange to say the OT canon should be what Jesus explicitly endorses, as this presents a couple of problems.

1) Who has decided this criterion, and on what authority?

2) How does one come to the knowledge of what Jesus explicitly endorsed? If you mean to do this by using the New Testament, then this presents further issues.

A) The problem of determining the New Testament canon, which would then be used to determine the OT canon

B) I really don't think that fairly doing this will actually result in the OT protestants use

To me the issue seems to be whether God will allow the Church to fall into binding error, despite having the mission to teach to the world He who is Truth. "Gates of Hell," etc. The early fidelity to authoritative declarations of the Church...I would be terrified the idea of His Bride being able to err in such manners would be a mere tradition of men, used to excuse breaking with the Church which God, as the ultimate and only source of authority, has endowed with authority and capacity to teach and feed the sheep of Christ. But I digress...

"But Jesus answered them: My Father worketh until now; and I work." God upholds Creation. I think the natural feeling of man would be toward Divine Conservation, as it is clear that things exist for a time and then are no more. Things fall apart. If there is some sort of existential inertia, it would appear to the natural man to be fairly weak. So at that level of simple appearance, it would seem natural to accept a Divine Conservation. Indeed, even the pagan religions would accept the Unknown God, an ultimate Source. God has allotted even some truth to the pagans, though mixed with so much error and, often, superstition. God bless us.

17. Alica Tanaka
Posted at 19:20:56 Monday March 8 2021

Has your view on existential inertia evolved compared to your post ( from two years ago?

18. Nigel Cundy
Posted at 18:00:28 Tuesday March 9 2021

Existential Inertia and my views on it

My view on existential inertia has almost certainly evolved a bit over time, as I have read more, but only (I think) in minor details.

I mentioned it in passing in that previous post, and re-reading it I don't see anything I disagree with. In particular, there is this statement here:

But, in any case, the idea of existential inertia is not something we should blindly accept, because the process of spontaneous emission shows that things don't have existential inertia. They don't naturally remain in the same state if they are left alone.

This seems to be a good summary of my position. Obviously, in this post I go into a lot more detail, since I am discussing the topic directly. As such I consider some counter-arguments, and have to be a bit more careful in my definitions and bit more nuanced in places. And, obviously, thinking through the topic to prepare for this post, and doing the research, also affected my ideas on the subject.

But the statement I highlighted above is still at the center of my argument; and I still reject existenial inertia for those reasons. So I think that is still a good one sentence summary of where I stand.

21. Chao Feng
Posted at 22:25:44 Thursday June 17 2021

I used to worry about this because I read Feser's Five proof of God before I read his other stuff and in that book, it seems to me that he presented the Aristotelian proof as dependent on existential inertia to be false without even mentioning the term "existential inertia" (which is super annoying and I have problems with all the proofs he presented in that book). But now that I have read Aquinas's First Way as presented in Summa contra Gentiles and Feser's Aquinas, I don't think the "argument from motion" depends on existential inertia to be false at all. I am only about 1/3 through your book "What is Physics?" One objection I could think of against the "argument from motion" is that maybe something could have a natural tendency to actualize certain potential (i.e., moves) without needing a mover. But intuitively that cannot explain the order of the reality (e.g., the stone moves when sth pushes it rather than move on its own). Are your "arguments related to the tendency towards a state of equilibrium in a complex system" similar to this? That if there is no unmoved mover then according to the second law of thermodynamics the whole world would just be a soup in equilibrium rather than the actually exciting reality we live in.

Hope what I said makes sense LOL.

22. Nigel Cundy
Posted at 17:52:54 Friday June 18 2021

The first Way

Dear Chao,

Thanks for your comment. I do make use of the tendency towards equilibrium in my version of the cosmological argument, mainly because it was relatively easy shortcut. I think that the argument can be presented without that just using the dependency of one cause on the other to show that it is an instrumental series, but it is a bit harder.

With regards to your question

One objection I could think of against the "argument from motion" is that maybe something could have a natural tendency to actualize certain potential (i.e., moves) without needing a mover

The point of the cosmological argument is, I think, to demonstrate that there must be at least one such thing: something which can move others without having being moved itself (with moved meaning a more general sense of change rather than just locomotion). Are you asking whether there could be something which eternally moves itself (and perhaps also moves others) without having been moved by something outside itself?

We need to be a bit careful here to distinguish between beings and states (or potentia). At least as I frame the argument, each link in the chain of causes is a particular state. So you can have a situation where the being existing in that state is caused by the same being in a different (previously actualised) state. This would be natural motion. The argument from motion attempts to show, however, that this state of affairs can't continue forever (just as we can't have a sequence of solely instrumental movers that are different beings); there must be something which exists that can move without having been moved itself. That "without having been moved" includes any purely internal changes in the being where it has a natural motion to change from one state to another.

23. Chao Feng
Posted at 20:57:12 Friday June 18 2021

Dear Dr. Cundy,

Thank you very much for your answer. I am converting to Catholicism from atheism so these (and your book) are very helpful for me on a personal level. You are quite right, I was mixing up a particular potentia with being. I think this clears my understanding. This could be the day I can start to call myself a theist (although I still need to clear my understanding of the Devine attributes.)

Thank you!



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