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“Existential Inertia” vs. Almighty God

Materialist philosophers, starting in the fifth century B.C. with Leucippus and Democritus, have claimed that physical reality has simply existed without any temporal beginning, thereby avoiding need for any type of transcendent spiritual creator. With Christianity, though, came belief that the world began in time as well as the concurrent claim that a purely spiritual and utterly transcendent God was needed to explain its creation ex nihilo et utens nihilo.

Since the Christian God was held to have created the world “out of nothing and using nothing,” the metaphysical principle which says that when a cause ceases causing its effect ceases was taken to imply that God not only caused the world to be created from nothing, but also, were he to stop creating it, it would fall back into nothingness. Thus was born the Christian doctrine that God continuously creates (conserves in existence) the entire cosmos – even if it had no beginning in time. This has become a central claim of Christian metaphysicians, including St. Thomas Aquinas (1225-1274).

Responding to this Christian belief, the recent counterclaim, known as “existential inertia,”1 has appeared. In essence, existential inertia provides a theoretical foundation for materialism’s constant stance that the world explains itself and has no need to be sustained by God’s conserving causation.

Like Newton’s law of inertia, which states that a body in motion tends to remain in motion and a body at rest tends to remain at rest, the concept of “existential inertia” maintains that (1) once a concrete object is in existence, it will persist in existence without any continuously concurrent sustaining cause, and (2) it would require new causal action to make it cease to exist. Thus, one of the most central theses of Thomistic metaphysics, namely, that all finite beings need an extrinsic cause to explain why they continue in existence, is replaced with an allegedly rational justification for Leucippus’s and Democritus’s original thesis of an eternal uncreated material world.

The Principle of Sufficient Reason

This fundamental metaphysical debate over how things exist requires examining the even more basic metaphysical principle of sufficient reason, since Christian thinkers insist that God provides to all finite beings their sufficient reason for continued existence. Instead, atheists maintain that concrete objects either (1) are their own sufficient reason for staying in existence, or else, perhaps, (2) since they already are in existence, they need no further reason for continued existence.

The Thomistic principle of sufficient reason states that everything needs a sufficient reason for its being or coming-to-be. “Sufficient reason” means an adequate and necessary objective explanation of something. Elsewhere, I maintain that all human reasoning follows this principle, since everyone knows that every claim anyone makes must somehow be supported:

To say that claims need support means that a statement or proposition must somehow be either (1) immediately evident or (2) that some extrinsic evidence proves it is true. A statement may be immediately evident either (1) because it is self-evident, as when I say every triangle has three angles, or else, (2) because it is immediately-known as when I say that I am presently experiencing some form of change or motion.

Human reason universally demands that what is not immediately evident must be proven through extrinsic evidence, which amounts to saying that reason demands a sufficient reason for everything – either in itself or from some other evidence.

And yet, since claims made in the form of propositions are made about reality, if the laws of reason do not apply equally to reality, reason becomes a useless instrument to know reality. Conversely, if reason is a valid instrument whereby to know the real world, then the principle of sufficient reason must universally apply to reality just as it does within reason itself.

Benignus Gerrity offers one of sufficient reason’s best defenses:

“The intellect, reflecting upon its own nature, sees that it is an appetite and a power for conforming itself to being; and reflecting upon its acts and the relation to these acts to being, it sees that, when it judges with certitude that something is, it does so by reason of compulsion of being itself. The intellect cannot think anything without a reason; whatever it thinks with certitude, it thinks by compulsion of the principle of sufficient reason. When it withholds judgment, it does so because it has no sufficient reason for an assertion. But thought - true thought - is being in the intellect. The intellect is actual as thought only by virtue of some being in it conforming it to what is; whatever the intellect knows as certainly and necessarily known, it knows as the self-assertion of a being in it. This being which compels the intellect to judge does so as a sufficient reason of judgment. Nothing, therefore, is more certainly known than the principle of sufficient reason, because this is the principle of thought itself, without which there can be no thought. But by the same token the intellect knows that the principle of sufficient reason is a principle of being because it is being, asserting itself in thought, which compels thought to conform to this principle.”2

Rejecting analytic philosophers’ attacks on metaphysical claims, philosopher Jacques Maritain, defends metaphysics’ prerogative to investigate the principles of being as such:

“We must beware of a fatal error, confusing metaphysics with logic. This mistake has, in fact, been made by the moderns, many of whom maintain that this being as such is a mere word, a linguistic residuum, or else that it is a universal frame whose value is purely logical, not ontological. According to them the metaphysician has fallen victim to human language, whereas in fact he passes through and beyond language to attain its intellectual source, superior to any uttered word. We must, therefore, understand clearly that the metaphysical intuition of being is sui generis and of powerful efficacy and therefore distinguish carefully being which is the object of metaphysics … from being as studied by logic.3

The Act of Existence and Its Sufficient Reason

Having established the ontological principle that every being must have a reason for being or coming-to-be, the question now is whether a being’s continued existence is adequately explained by “existential inertia.”

“Sufficient reason’s” critical relevance to “existential inertia” becomes clear when one realizes that every being, even one allegedly possessing “existential inertia,” absolutely requires a sufficient reason for its existence or coming-to-be. That something persists in existence still requires a sufficient reason for that persistence.

Whatever other significations metaphysicians give to the term, “existence,” in this essay, I refer primarily to whatever it is in something that actually differentiates it from absolute nothingness. For this reason it is called an “act of existence.” Kant correctly points out that existence is not a predicate in the sense of adding a property to something. Still, existence is that act which differentiates all beings and their properties from non-being.

The act of existence needs a sufficient reason for doing whatever it does to make something be real.

Moreover, existence manifests the meaning of the term, “power,” since power refers to the ability to do or make something – and what existence does is to make something be real, that is to say, to make it to be an actual being.

So, the natural question is how great a power is required to explain that something exists in reality?

Sufficient Reason in Causes and Effects

While every being requires a sufficient reason, a logical distinction arises when we ask just “where” this sufficient reason is to be found. A sufficient reason’s locus for explaining something can logically be divided into three possibilities: (1) a thing may be explained by a sufficient reason entirely extrinsic to itself, (2) a thing may be explained by a sufficient reason entirely intrinsic to itself, or (3) a thing may be explained by reasons that are partially intrinsic and partially extrinsic to itself, with the combination of both intrinsic and extrinsic reasons constituting sufficiency.

By definition, any being whose sufficient reason for being is not totally within or intrinsic to itself is, to that extent, dependent upon another for its sufficient reason, and thus, it is called an “effect.” Conversely, any being which serves as an extrinsic sufficient reason is called, in that precise respect, a “cause.” Finally, anything whose sufficient reason for being is entirely intrinsic to itself is simply its own sufficient reason.

While St. Thomas Aquinas gives no direct argument to prove the power needed for a thing simply to exist, he does offer an argument regarding the power required to make something come into being ex nihilo et utens nihilo, that is, by way of direct creation.

In his Summa Theologiae, while answering an objection that only a finite power is needed to produce a finite creature by creation, St. Thomas proposes the following demonstration to prove that infinite power is required in order to create any being at all:

“It must be said that the power of the maker is measured not only from the substance of the thing made but also from the way of its making; for a greater heat not only heats more, but also heats more swiftly. Thus, although to create some finite effect does not demonstrate infinite power, nevertheless to create it from nothing does demonstrate infinite power.... For, if a greater power is required in the agent insofar as the potency is more removed from the act, it must be that the power of an agent [which produces] from no presupposed potency, such as a creating agent does, would be infinite; because there is no proportion of no potency to some potency, as is presupposed by the power of a natural agent, just as there is [no proportion] of non-being to being.”4

Now one might be tempted to agree with St. Thomas’s conclusion, but for the wrong reason – since it seems intuitive that “thrusting” a thing into being requires transcending a gap between non-being and being that has no middle through which to pass, and hence, requires infinite power to accomplish. But between non-being and being there is no real relation to measure, since all real relations require that both extremes in the relationship be real – and non-being is not real. Hence, this argument fails.

Rather, St. Thomas’s actual argument is cast in terms of potency and act and the principle that greater power is required to produce the act when the potency is more removed [magis remota] from the act. But, potency and act here can be replaced by the more evident concepts of non-being and being. For, something with fewer real properties may be changed into something with more real properties and that change can be measured in terms of the power required, since having certain initial properties can function as a basis against which to measure how many more additional properties are required to produce the thing that comes-to-be.

Thus, changing non-living matter into a cognitive organism requires more power than would be needed to change an already living organism into a cognitive organism, since the living thing already has more of the properties belonging to a cognitive thing. In that manner, the remoteness of the thing to be changed measures the power needed to produce that which comes-to-be in change.

But this way of reckoning does not apply to the creation of being or existence absolutely considered, since what does not exist at all offers no preceding qualities from which to measure the remoteness to that which comes-to-be, namely, something that really exists. For, the act of creation produces existence absolutely, not merely this or that form of existence. As St. Thomas puts it, “Now to produce existence [esse] absolutely, not as this or that [form of existence], belongs to creation.”5

Hence, while it appears possible to measure the remoteness of something with fewer or less perfect qualities of being to something with more or more perfect qualities of being, it is inherently and objectively impossible to measure the remoteness of non-existence to existence absolutely considered, since, as St. Thomas notes, “there is [no proportion] of non-being to being.”6

Since, then, it is impossible to measure the remoteness of non-existence to existence absolutely considered, it is impossible, in the case of producing being itself, to measure the power required for creation. Hence, the power required to create finite being is, by its very nature, immeasurable. But what is immeasurable is infinite. Hence, infinite power is required to create finite being, since there is no pre-existing being from which to produce it.

Now, it might be objected that “remoteness” assumes measurement between two really existing things, whereas, in the case of creation there is not even a real relation of remoteness, since non-being does not exist. But, this only underlines the impossibility of measuring the power required to create, since there is simply no standard of reference against which to measure or judge its limit.

Following a slightly different approach, the prior state of a being provides a limit against which to measure the qualities produced in the succeeding state, and thus, the power needed to produce them. In this way, what exists, but is non-living, provides a limit to the needed power insofar as something already has existence, even though it lacks the property of life compared to a resultant living organism. But non-being, since it does not exist at all, provides no such limit against which to measure the existence of that which comes-to-be after the effect is produced. Therefore, the power needed to produce being from nothing has no limit by which to measure it – meaning it is limitless or infinite power.

Why it Takes Infinite Power for Anything to Exist

While the preceding argument proves that infinite power is required to create being ex nihilo et utens nihilo, it still must be determined whether similar reasoning applies to what is already in existence, that is, why something could not simply continue to exist through existential inertia without the need for anything whatever causing it to be.

Even if one grants that infinite power is needed to cause a finite thing to begin to exist, one could still take the position maintained by materialists, such as Democritus, that no new beings ever come-to-be at all. Rather, matter is eternal and complex things are merely combinations of what already exists from all eternity with no cause of existence of anything being needed. No infinite power is required because nothing new ever comes-to-be from non-being. No power is needed to explain continued existence at all, since things just continue existing through existential inertia.

Of course, the preceding defense of existential inertia applies solely to the new existence of complete substances. Existential inertia has no defense against the coming-to-be of what I call, in another essay, “new existence” in the form of accidental changes, such as motion.

But complete beings or substances do not “just exist” without a sufficient reason, which “does something,” namely, by functioning as an adequate and necessary objective explanation of why they exist. The sufficient reason must have the power to account for this reality.

Since proponents of existential inertia insist that it would take some external cause to destroy a thing already in existence, the being in question must not be being caused to exist by another. That is because what is caused by another to continue existing would receive its sufficient reason for existing from another. Removing that extrinsic sufficient reason would “automatically” make the caused being cease to be, since it would have lost its extrinsic sufficient reason for existing and no intrinsic one was postulated. As St. Thomas puts it, “… with the cessation of the cause, the effect also ceases….”7

Thus, what must still be explained is this logically remaining intrinsic sufficient reason whereby any finite being continues to be actually real as opposed to being nothing at all. A finite existent does not just happen to exist, since it is “doing something,” namely actually existing. This means that it also must have a really existing intrinsic sufficient reason by which it has the power actually to exist.

So, the question remains: “Can the power (intrinsic sufficient reason) by which a finite existent exists be measured or is it immeasurable, that is, infinite?”

The principle of sufficient reason mandates that there must be a reason for something already existing to continue to exist. If continued existence required no sufficient reason, no power would be needed for existential inertia to occur. But since a real sufficient reason must be operative in keeping something in existence, this would mean that the finite being must continually actively account for its own existence.

Aside from the fact that the sufficient reason needed to account for finite existence is intrinsic to the being now under discussion, an argument similar to the earlier one above shows that it still requires infinite power to account for a finite being’s existence.

No matter how distant a given being is from another given being, non-being is more distant from both of them than they are from each other, since there is not even a proportion of non-being to being, as St. Thomas points out.8 This shows that non-being is immeasurably or infinitely removed from being.

It is inherently and objectively impossible to measure the remoteness of non-being to being, since there is not even a proportion of non-being to being. For this reason, it is likewise impossible to measure the power required in order to account for a finite being’s existing as opposed to its not existing at all.

Furthermore, as noted above, even though a being itself is finite, the lack of any real relation between non-being and being only serves to show that there is simply no standard against which to measure the power required to explain any finite being’s existing. As St. Thomas notes, the power required is known, not only from what is made, but also from how it is made – and there is no way to measure the act by which any being – regardless of what it is -- is distinguished from nothingness.9

The power required to explain why anything exists at all, as opposed to not existing, is, by its very nature, immeasurable, that is to say, infinite.

Even regarding a finite being whose existence does not have a beginning, but one where something is causing it to exist from all eternity, similar reasoning prevails. Infinite power is ultimately required to explain why any being whatever exists as opposed to non-being – if not in itself, then in its cause.

Therefore, to say that a finite being is its own sufficient reason for continuing to exist amounts to saying that it is infinitely powerful and essentially creating itself, which is impossible for a mere finite being to be and to do!

Thus, whether something (1) is caused by another or (2) explains its own existence, infinite power is required to explain its existence. But infinite power cannot reside in a finite being or even in a collection of finite beings. Therefore there must exist an Infinite Being, the God of classical theism, who alone can possess and manifest the infinite power required to create and conserve in existence all finite things, including the entire physical world.

“Existential inertia” turns out to be metaphysically impossible. Rather, all finite things are created by God and held in existence by his continued creative causality. Absent God’s conservation of all things in existence, they would all fall back into nothingness.

The bare existence of anything at all necessarily implies the existence of Almighty God as the only being possessing the infinite power needed to account for the existence of anything at all.

“Existential inertia” vs. Almighty God?   Almighty God wins!


  1. Beaudoin, J. The world’s continuance: divine conservation or existential inertia?. Int J Philos Relig 61, 83–98 (2007). https://doi.org/10.1007/s11153-007-9113-1
  2. Benignus Gerrity, Nature, Knowledge, and God (1947), 400-401.
  3. Jacques Maritain, A Preface to Metaphysics (1939), 27.
  4. Summa Theologiae, I, q. 45, a. 5, ad. 3.
  5. Summa Theologiae, I, q. 45, a. 5, c.
  6. Summa Theologiae, I, q. 45, a. 5, ad. 3.
  7. Summa Theologiae I, q. 96, a. 3, ob.3.
  8. Summa Theologiae, I, q. 45, a. 5, ad. 3.
  9. Ibid.
Dr. Dennis Bonnette

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Dr. Dennis Bonnette retired as a Full Professor of Philosophy in 2003 from Niagara University in Lewiston, New York. He taught philosophy there for thirty-six years and served as Chairman of the Philosophy Department from 1992 to 2002. He lives in Youngstown, New York, with his wife, Lois. They have seven adult children and twenty-five grandchildren. He received his doctorate in philosophy from the University of Notre Dame in 1970. Dr. Bonnette taught philosophy at the college level for 40 years, and is now teaching free courses at the Aquinas School of Philosophy in Lewiston, New York. He is the author of two books, Aquinas' Proofs for God's Existence (The Hague: Martinus-Nijhoff, 1972) and Origin of the Human Species (Ave Maria, FL: Sapientia Press, third edition, 2014), and many scholarly articles.

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