A Proof for God’s Existence

by Travis Fentiman

Sept. 2024

A Proof for God’s Existence

Can God be Proven?

Can God be proven to exist?¹ The Bible says God is “upholding all things by the word of his power” (Heb. 1:3) and “in Him we live, and move, and have our being.” (Acts 17:28) If this be true, as Christians believe, then it should be for all created things that their existence and continuance has no adequate or sufficient explanation or grounding in the things themselves, that is, in their own nature, but only because God wills them to exist.

¹ Francis Turretin (d. 1687), a pillar of Reformed Orthodoxy said, speaking for the Reformed: “Can the existence of God be irrefutably demonstrated against atheists? We affirm.” Institutes, vol. 1, 3rd topic, question 1, p. 169. Gisbert Voet (d. 1676), likewise: “Whether God is able to be proved and demonstrated from the light of nature? It is affirmed against the Socinians.” Syllabus of Theological Problems (Utrecht, 1643), pt. 1, sect. 1, tract 2, I. ‘Of God’, 1. ‘Whether there may be a God?’.

If this be the case: (1) this should be able to be seen from examining the nature of things themselves and how they are caused, that is, by the light of nature (without Scripture), and, (2) from the characteristics of nature or its laws, God must be the only sufficient explanation, both in the orders of knowing and being,† for the existence and continuance at every moment for all created things.

† That is with respect to epistemology and ontology (or metaphysics).

This must be qualified just a little. One would not expect from only certain properties of nature to be able to derive everything about God. However, if such necessary derivations can be made, that which will be known of God will be distinctive to Him, showing that it is God one is considering, this being in accord with Rom. 1:20: “the invisible things of Him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead.” This understanding consists with the Westminster Confession (1646).¹

¹ WCF ch. 21.1, “The light of nature showeth that there is a God, who hath lordship and sovereignty over all; is good, and doeth good unto all;”
ch. 1.1, “the light of nature, and the works of creation and providence, do so far manifest the goodness, wisdom, and power of God, as to leave men inexcusable…”

About this Proof

No originality is claimed for the substance of this proof. The general tenor of it derives from Aristotle, through Aquinas and most lately through Edward Feser.² I have adapted it in my own style. The Dutch reformed theolgian Peter van Mastricht (d. 1706) used a very similar proof.³

² Feser (b. 1968) is a professor of philosophy and an analytical Thomist. Feser, Five Proofs of the Existence of God Pre (Ignatius Press, 2017), ch. 1, ‘The Aristotelian Proof’, pp. 17-68
³ Mastricht, Theoretical-Practical Theology (RHB, 2019), vol. 2, bk. 2, ch. 2,sect. 2, pp. 45-46.

You can call this proof of God, “The Aristotelian Proof from Change,” though, it does not hang on Aristotle, Aquinas, Mastricht, Feser or myself. It derives from nature itself, necessarily, and is able to be understood by any rational creature in any place at any time. It is a universal testimony to God’s existence. (Ps. 19:1-4)

The proof proceeds by the way of causality, one of the three ways the Christian tradition has taught God may be generally known by through acquired knowledge.º It does not start with things more fundamental and absolute in their being than God, and then derive from these God, who must be consequently lesser. Rather, it starts with things less absolute and fundamental than God and works backwards, so to speak, by their necessary connection to Him, to show that an absolute God must be. That is, the way of knowing need not always follow the priority or ultimacy of being.

º See ‘On the Three General Ways God is Known by Acquired Knowledge: the Way of Causality, Negation & of Eminence’. This is not to exclude an innate knowledge of God: ‘On Innate Knowledge of God in distinction from Acquired’.

It ought not to be thought this proof is the only way God’s existence may be demonstrated, as other aspects of being and creation, by their distinctive traits, may be expected to show further things about the character of our God.

First, 1. Preliminaries to the proof will be given, then 2. the proof will be proven, then 3. it will be shown that many more attributes of God may be derived from what has been proved, showing that it is God we are dealing with. 4. Two objections will be resolved, and lastly, 5. we will close.

1. Preliminaries to the Proof

1.1 Change

Change occurs. Besides that we acknowledge and assume this in our daily actions (such as in reading this proof), and couldn’t live without doing so, to rationally deny change occurs, one would have to think of a reason for this, possibly another, and conclude that change does not occur. This involves change. That change occurs is undeniable; therefore it is true.

Change necessarily involves the actualization of a potential, that something has a potential for something, and that potential thing comes into being or is made actual. That is, change cannot be sufficiently explained or justified apart from potentiality and actuality. Potentiality and actuality must lie beneath all change, though these metaphysical concepts cannot be seen of themselves.

Change occurs, therefore potentiality and actuality exist, functioning in relation to each other.

1.2 Train Cars

A flatbed train car has much potential. Given its axles and wheels it can roll down the railway. It can also hold many heavy things on it off the ground. Yet there are many things a train car has no potential for. If you see bunny rabbits hopping around the car and hear violin music, you would look around for their cause because you know train cars can’t, by their nature, turn into bunnies or produce bunnies or violin music. A metal train car doesn’t have those potentials, due to its unique nature in being a train car.

One may think perhaps: the train car could be melted down and turned into a metalic violin with metalic strings and produce violin music. Perhaps it may, but then it wouldn’t be a train car with axles and wheels that could hold heavy things off the ground and roll down the rail. You also wouldn’t be seeing a flatbed and hear violin music at the same time. If something is a train car, it can’t produce things beyond what its nature has the potential for.

If the car sits on a flat railway, how long will it sit there till it moves down the railroad? Of course not until something else comes and pulls it along. The flatbed has no ability or potential to move itself or to activate its own potentials. Something else has to do that.

1.3 The Law of Causality

Say two train cars sit on the railroad next to each other. Both have the potential to move. Yet the potential of the one never moves the other. Why? Because the one flatbed’s potential to move is not actual; it is not actually moving, and that is what it would take to move the second flatbed, to activate its potential to move.

That one thing must be moved by another is not only a common observation all around us, it must be true for everything that has potential, precisely because something not actual cannot do anything. A possibility does not exist as anything but a possibility. These thngs must be true by the distinct natures of what potentiality and actuality must be. The principle is called the Law of Causality:

Something potential can only be made actual by something actual.

This is not only universally true by empirical experience, but it must be true by definition from the laws that constitute nature, given change. If change occurs, it must be done by something actual. Something must bump into or pull the train car before it will move, because it has no nature or potential to move itself.

1.4 Ordered Series of Dependent Causes

In a train of many cars going down the railroad there is an ordered series of dependent causes: each car’s potential is being activated to move by the actual car in front of it in a series where one car is dependent on all those in front of it. The train engine at the front is pulling all the cars after it; it is doing all the work in one respect, through the nature of those cars and their causal relations.

Of course we are not actually interested in train cars. Each car stands for something that changes, namely any and everything we see around us. Ordered series of various causes surround us, and we are part of them.

The issue we are getting to is not dependent on time, nor concerns change through time. Take the series of train cars in a moment of time. Each one still depends by way of causation and dependence on those in front.

Take a case where there is no movement or change through time: You may be sitting on a chair, which is keeping you off the floor. The chair is being held up by the floor, the floor by the building supports, which are resting on the foundation, which is being held up by the ground. The ground has more ground underneath it, and further factors are causing that ground to be the way it is, such as gravity and various forces science is concerned with. Go as far along in that series as you can. Here is a hierarchical series of ordered, dependent causes, always existing in our universe.

2. The Proof

2.1 The Problem

You see a clearing in the trees with flatbed train cars rushing through. Seeing as a flatbed has no ability by its nature to move itself, what is moving each one? You might say, “Well, the train car in front of it is pulling it.” Well that is true, but that flatbed also has no power to move itself; what is pulling that one?

You look a little more around the edge of the trees and see several more train cars ahead in the line. What is pulling those? Each further car activating the potential of the one behind it still needs its own potential activated by another.¹

¹ If you don’t agree, try denying the Law of Causality above and see how that works out in daily life. See Feser defend the principle in Five Proofs, ch. 1, ‘Common Misunderstandings’, pp. 38-68.

Clearly no finite number of flatbeds in the series is going to resolve the issue. If there are 100 flatbeds, you will then need 101, then 102, 103, 104, etc. You may think, “If no finite number of flatbeds will help, there must be an infinite number in this series, each further flatbed pulling the other.” Yet if no flatbed by its nature has inbuilt power to move itself, neither does an infinite number or series of flatbeds.

Some may claim this commits the fallacy of composition, that the qualities of parts are not necessarily those of the combined whole: if each lego piece weighs one ounce, a wall of them does not weigh the same. Yet not every composition of qualities functions the same. If each lego is red, the whole wall of them is red. What’s the only color of an infinite wall of red legos?

What kind of quality and composition then are we concerned with? If each flatbed has potential and therefore can’t move itself, and an infinite line of them is moving and changing, and thus has potential, it can’t move itself either.

Well, perhaps the infinite series of train cars is going in a circle. That’s not going to work, for the same reasons. The conglomerate of an infinite number of things that cannot move themselves still does not have a nature to be able to move itself, even in a circle. So the flatbeds’ moving is left unexplained, as their natures, even strung together infinitely in whatever shape you desire, cannot account for it.º

º Turretin in addressing that a thing cannot be the cause for its own existence, which we will get to: “such a circle is impossible; for suppose it were true, it would follow that the same thing was made by itself and was the cause (mediately at least) of itself.” Institutes 1:170

But perhaps it’s a whirlpool, like the whirpool of secondary causes all around us. What moves the infinite, whirpool of dependent causes (grant its existence for the sake of argument), if the whirlpool has nothing in it able to move itself and, as the whirlpool’s potential (which it must have, as it changes) must be activated by something outside itself? Adding another whirpool, universe, dimension, finding of science, big bang, etc. is not going to help.

Now you look and see flatbed train cars rushing through the clearing in the trees with bunnies hopping around and you hear violin music playing. If the bunnies and violin music can’t come from the flatbeds (whether from one, many or infinite of them), but must have another cause, so must the rushing motion of the flatbeds, whether the series is infinite or not. If violin music can’t produce bunnies, an infinite amount of violin music isn’t going to produce bunnies. If an infinite line of flatbeds can’t produce bunnies, it can’t produce its own motion.

So far there is no sufficient warrant, justification or power for the train of dependent causes, or a whirlpool of them, to be moving.

2.2 The Only Sufficient Grounds

The only way to (1) stop the infinite regress and (2) sufficiently account for the movement or change is if one has something like a train engine: something able to move everything else without needing to be moved.

By definition that thing must have no potential needing to be made actual by another. If it had any potential at all, it would need another to actualize it and hence it would not be first (which continues the series and the problem). Nothing cannot move things as it has no nature to do so. That something needed to explain the inescapable movement of everything else must be actual and must be purely actual.¹

¹ See ‘On God as Pure Act’.

If that thing is purely actual with no potential, it has no potential to change. It must be unchangeable. As it is completely actual, it must exist. As it is unchangeable, it cannot have come into existence. As such its existence is necessary: it could not not exist. As things change and move, it only can be the fullest and ultimate cause of those things moving and changing. Therefore it is moving and causing all things, through their natures and through their causal relations.² It is the first mover, which is unmoved.

² On concurrence, contra Occasionalism, see ‘On Occasionalism, Secondary Causes & Concurrence’.

Note the principles we are concerned with do not hinge on time. The issue is not that a long time ago some first cause had to have tipped the first domino of the series over. That puts the issue historically before our time, and such a mover may not be needed after the chain reacton gets going. Rather, if change occurs at all, right now, if hierarchical series of dependent causes exist at all, right now or ever, there is an unmoved mover that is pure act, unchangeable, necessary in its being, therefore eternal, needing no cause, which is the fundamental cause of all things with potential or that have the ability to change.

2.3 From Change to being Upheld in Existence

If something with potential changes, its potential being made actual, being brought into at least a mode of existence it was not before, it also possibly losing a mode or part of its previous existence (just as in life we don’t remain in every way the same from conception through all life’s stages to death, gaining and losing existent features and potentials with time), so if a thing or person’s existence is constantly changing, coming into being and going out of being, the thing or person not having power to sustain itself whole and intact (that is, unchanging), and if a thing or person is fundamentally one (and not another, or two, or both), then we do not have grounds in our nature to uphold our own existence, nor does any other changing thing.

Thus if something changes (which implies it has parts at some level, it remaining in part and losing a part) and cannot hold part of itself in existence (due to the potential to being acted upon by other things), then it can’t hold its whole existence, or its existence per se, in being or actuality. If it can’t do the lesser, it can’t do the greater.

The actualized part of every changeable thing must be a potential being actualized. If so, then that actualized part could be not actualized and only be potential, making the whole thing actually nothing, only potential. Hence not only a thing’s change, but the thing’s very existence as something actual must be dependent on the unmoved mover.¹

¹ Turretin: “nothing can be the cause of itself (for then it would be before and after itself), it is also certain that we must grant some first and unproduced being from whom all things are, but who is himself from no one.” Institutes 1:170

To evaluate how much this conclusion applies to, consider for a moment: How much of the universe doesn’t change?

This first cause, the unmoved mover, we call “God”. If change occurs, God exists. If anything changeable exists, that is, anything with parts or variation of any kind, it not being utterly simple, its existence must be contingent on or dependent upon God. Thus God exists.

3. The Unmoved Mover is God:
further Attributes

Some may not be used to thinking of God as an unmoved mover. Yet is not the first cause of all things God? If God is anything He is that. But many more attributes may be derived from the unmoved mover being pure act,ª which will show that we are dealing with God.

ª This is not accidental. Just as (1) the attributes of a thing derive from its kind of existence, so (2) if God’s existence or being may be established and that it is of itself, or from itself (aseity), (3) its absoluteness, independence and primacy being herein established, (4) and everything else must flow out of this first principle and (5) must be systematically related to it, it ought to be expected that many attributes of the first principle may be further drawn out. See the footnote below on classic reformed theology and Mastricht.

There can only be one unmoved mover. If there were two, if they were the same in every respect, they would be the same and only be one, not two. If one differs from the other it must have some property the other does not. Hence the other would have a potential not actualized. Yet this being must be pure act and cannot have potential. Hence there can only be one unmoved mover.

All matter, existing in space, must therein have extension. If something has extension it can logically be distinguished into parts. If something has parts one part is not the same as the other part (else there would be no parts). As one part must be a different potential actualized than the other part, so potential must exist in every material thing, and hence all material things are changeable. But the unmoved mover is fully actual, cannot have parts and must be immaterial or incorporeal and absolutely simple.

If space and time have extension and/or parts in some respect, and change, the first cause must be the cause of them. But space is extended, one part of it is not the same as another part; and one part of time, having extension, like the past, is not the same as another part, like the present or future. Hence the first cause must be outside space and time. But this is to be effectively omnipresent and infinite beyond any infinity space or time may be capable of.

The cause that brings all things outside of itself to pass has power. This cause, being pure actuality without limitation, has infinite power.

As evil is a deficiency from what is good, so evil can only exist (1) as a relation to what is good, and (2) in something that is otherwise (in some measure) good.¹ Hence absolute evil is impossible. As good is a transcendental, existing in all being, is more foundational than evil, and as the first mover’s being has no deficiency or potential and is pure act, fully fulfilling its own nature, it must be infinitely good. If so, the unmoved mover must also be wholly righteous, and hence just.

¹ Rom. 3:23, “For all have sinned, and come short of the glory of God.” See also, ‘On the Negative & Positive Aspects of the Nature of Evil’, ‘That Created-Being, even in Evil-Workers is Good & is Willed & Loved of God as a Good’, ‘What Makes an Act Sinful?’, ‘What is ‘Good’?’.

All that is in an effect must be (in some way) in its total cause (or else the total cause could not produce the effect) in a way consistent with the total cause’s nature.² Thus the first cause must have in it, in some way consistent with its nature, the perfections of all that is created.³ As all possibilities are grounded upon the nature of something actual, so that which is pure actuality is the ground of all possibilities.† Hence the first cause is that infinitely perfect being of which none greater can be conceivedª (not that human conception limits the first cause of human conception).

² This is called the Principle of Proportionate Causality. See Feser illustrate and defend it in Five Proofs, ch. 1, ‘Informal Statement of the Argument: Stage 2’, pp. 32-33 and throughout.

³ This principle uses the Way of Negation in excluding all that which is imperfect or inconsistent with God’s nature, and the Way of Eminence, in attributing unto God, the cause of our perfections, all that is good and perfect. Stephen Charnock: God “Must be infinitely perfect. Since man knows he is an imperfect being, he must suppose the perfections he wants [lacks] are seated in some other being, which has limited him, and upon which he depends. Whatsover we conceive of excellency or perfection must be in God; for we can conceive no perfection but what God has given us a power to conceive. And He that gave us power to conceive a transcendent perfection above whatsoever we saw or heard of, has much more in Himself, or else He could not give us such a conception.” The Existence & Attributes of God, ‘On the Existence of God’ in Works (Edinburgh: Nichol, 1864), p. 151 See also ‘On Divine Perfection & Perfect Being Theology’.

† See especially Samuel Rutherford at ‘On Possibilities & Hypotheticals’.

ª See ‘On Divine Perfection & Perfect Being Theology’.

While we could go on for some time deriving many of the attributes of the unmoved mover from nature’s light, such an exercise in natural theology is unnecessary here.° It is clear we are dealing with God.

° While classic reformed theology during the Post-Reformation varied with how far God’s attributes might be derived from nature’s light alone, especially with regard to epistemology after the Fall (in distinction from metaphysics from pure-nature), yet there is good reason, said Mastricht, to think “all the attributes of God are established in this primacy” of God’s being. All attributes of things depend upon and flow out of the characteristic being of the thing. If one establishes the greater, one establishes (at least theoretically) all the lesser. Thus if God’s “aseity [from Himself-ness], independence and primacy” (which things inhere from being pure act) are proved, from this may be deduced, according to Mastricht, God’s unity, immutability, infinity, simplicity, life, intellect, will, omnipotence and “the virtues of the intellect and will—wisdom, goodness, grace, holiness, and others…” Theoretical-Practical Theology, vol. 2, bk. 2, ch. 3, sect. 16, pp. 84-85 In most of the subsequent chapters on God’s attributes Mastricht has a specific section on how each attribute may be derived “from reasons”.

To summarize, the unmoved mover must be: the fundamental cause of all things that have the ability to change, be pure act, unchangeable, necessary being, needing no cause, nor capable of it, be singular, eternal, immaterial, having no parts, simple, infinite, omnipresent, omnipotent, all-good, all-righteous, all-just and perfect in every way possible. This is God.

4. Two Objections

To resolve an objection or doubt: It may seem if God has many attributes, then God has parts and cannot be utterly simple, and therefore must be contingent, have potential and even be caused, and hence not be God.

The attributes of God appear to us, and must appear to us as manifold, as the finite cannot contain the infinite. Yet as white light when refracted through a prism spreads out into all the colors of the rainbow, so all God’s attributes flow from the character of his one, absolute being, He being a being that is just all-powerful, good, righteous, just, etc.

If one cannot fully and perfectly conceive of God’s infinite, absolute, simple being, then necessarily God must be understood by finite, extended, temporal creatures with parts through the manifold rays of his harmonious attributes revealed and dispersed through the variegated finite realm, over time.ª

ª For more on this, see ‘On the Manifold Attributes of God in Relation to his One Being & Will’.

Second objection: You have started with and argued from metaphysics and the laws of logic for God; hence those things must be greater and more absolute than your God.

The conclusion is false and does not follow. The laws of metaphysics and logic are necessarily grounded on the absolute being of God,† that He is (“I am”, Ex. 3:14; εγω ειμι, Jn. 18:5-6), and therefore He is what He is, and not another (“I Am That I Am”, Ex. 3:14). God cannot be that which He is not, and that not simply by logic, but by his Being.

† See especially Samuel Rutherford at ‘On Possibilities & Hypotheticals’.

Without God the laws of metaphysics and logic would not exist, nor could. Because God is, the laws of metaphysics and logic, just like his manifold attributes, hold. If the laws of metaphysics and logic exist (to deny this is self-contradictory), having being, and they are plural and have variation and parts in some respect, not being absolutely infinite, then God must uphold them; and God exists.

If the laws of metaphysics and logic tell us something about the structure of reality and necessity (respecting being and thought respectively, the former being more fundamental), it is because God is ultimate, necessary reality. Those laws’ perfections reflect by God’s communication and their participation something of his Being.†

† See on, ‘On the Communicable Attributes & Participation’.

Given that metaphysical and logical laws are secondary to God, one can reason by them unto God-Absolute, just as one can epistemologically start with contingent creation, recognizing it (as such is in our capacity), and see by reason and the connection of things God must be the absolute foundation for these secondary things, as we have so done in this proof.

5. Close

To summarize the proof: If change occurs, God exists. If anything exists, God must exist, and be upholding all else in existence. God cannot not exist. This can be known by nature’s light, as it is seen from looking into nature that nature does not have sufficient grounds within itself for its own change or existence, this confirming Heb. 1:3, that God is “upholding all things by the word of his power,” and Acts 17:28, “in Him we live, and move, and have our being.”

For a further, more detailed demonstration of this proof from change, which also answers further objections to it, see Feser’s excellent Five Proofs of the Existence of God, ch. 1, ‘The Aristotelian Proof’, pp. 17-68.

After all this we can see how in a natural way God “puts no trust in His holy ones, and the heavens are not pure in His sight.” (Job 15:15, MEV) Yet how much more must it be true morally to us who are so far from perfect, who fall so far short of God’s glory and who have transgressed his goodness all around us so often and constantly. How shall we ever show our face before our ever present, righteous God?

If we cannot escape Him, let us flee unto Him, under the provision He tread out Himself for us. He first came to us (Jn. 1:11) as Jesus of Nazareth (1 Tim. 3:16), the Righteous One (1 Jn. 2:1), taking on our flesh (Rom. 8:3), suffering and dying unjustly (Isa. 53:1-9), not for Himself (Isa. 53:4-6, 8), to make an eternal satisfaction for sinners (Isa. 53:10-11), rising again from the dead the third day (1 Cor. 15:4), as none has power over Him (Jn. 10:18).

The Almighty uses the weakest means (1 Cor. 1:24-29), even a message of events in the Scriptures (1 Cor. 1:17-31), credible at every point (Lk. 1:1-4), though unseen to us (Jn. 20:29), to spread the knowledge of Jesus the Christ (Isa. 53:11), the Almighty Savior (Acts 5:31), who saves all that come unto Him (Jn. 6:37) by his own righteousness (Rom. 3:22). “The gospel of Christ… is the power of God unto salvation to every one that believes.” (Rom. 1:16) In coming to the Lord through the covering of Christ’s blood we are brought into eternal peace with Him and into all the fruit of his communion and highest loves. (Rom. 5:1-2)

God’s ways must be higher than ours (Isa. 55:8-9). If this be so in the natural realm (Isa. 55:10-11), how much more in God’s free, gracious choice and way to save sinners (1 Tim. 1:15), springing purely from his good pleasure (Eph. 1:4-12)? The Biblical Scriptures and saving Christian Gospel find all men condemned of themselves (Rom. 2:1-3), tell us to cease from man (Isa. 2:22), yet bear God’s extraordinary grace and love to the undeserving (Rom. 5:6-8) and have the breathings of divinity all over them (2 Tim. 3:16-17): the Scriptures and the Christian good news, by their very nature, cannot have been produced by man (Jn. 6:60-69).

There is a reason this message and what it speaks of resonates with and is the only thing that can fulfill the inmost depths of our being (1 Cor. 14:25), because it is from our Creator (Isa. 43:1). His living, Holy Spirit confirms it. (Jn. 16:7-8; Rom. 8:9)

If God be perfect and every rational action has a purpose, can God make man except God’s ultimate purpose in doing so, and man’s also, be for the highest good, namely for God Himself? (Rev. 4:11) If man’s chief and highest end, or the meaning of life, therefore is to glorify God and enjoy Him forever, one cannot find or fulfill their own flourishing or satisfaction except in fully living unto the Lord (Mt. 22:37-38) and being full of Him through our Savior Jesus Christ. (Jn. 14:21-23; Eph. 1:22-23) If He be our reward in this life (Gen. 15:1), He will surely be our reward in the next. (Ps. 16:10-11)

“Jesus Christ, whom having not seen, ye love; in whom, though now ye see Him not, yet believing, ye rejoice with joy unspeakable and full of glory: receiving the end of your faith, even the salvation of your souls.”

1 Pet. 1:7-9

Related Pages

Light of Nature

Natural Theology

On the Three General Ways God is Known: Way of Causality, Negation & Eminence

On Divine Perfection & Perfect Being Theology

Of God, the Knowledge of God & of his Attributes

Simplicity of God