Leibniz’ Contingency Argument

Why does the universe exist rather than an empty void? Gottfried Leibniz wrote, “The first question which should rightly be asked is: Why is there something rather than nothing?” Thus, he articulated the argument known as Leibniz’ Contingency (or Cosmological) Argument.

This blog is only meant to give a general overview of the argument rather than provide a detailed account of the wealth of material surrounding Leibniz’ claim. The argument is modified from the original source, but it is as follows:

  1. Everything that exists has an explanation of its existence, either in the necessity of its nature or in an external cause (a version of the Principle of Sufficient Reason).
  2. If the universe has an explanation of its existence, that explanation is in a necessary being.
  3. The universe exists.
  4. Therefore, the universe has an explanation of its existence (from 1 and 3).
  5. Therefore, the explanation of the universe’s existence is in a necessary being (from 2 and 4).
  6. Conclusion, a necessary being (God) exists.

The logic here is sound. If the premises are true, then the conclusion necessarily follows since this argument is deductive, but are the premises true?

Premise 1: Everything that exists has an explanation of its existence, either in the necessity of its nature or in an external cause (a version of the Principle of Sufficient Reason).

According to Leibniz in his treatise The Monadology, “no fact can be real or existent, no statement true, unless there be a sufficient reason why it is so and not otherwise….” Leibniz believed his question as to why something exists rather than nothing must have an answer. For Leibniz, the idea that the universe (or even God) could exist as a mere brute fact was unfathomable. This statement came to be known as the Principle of Sufficient Reason (PSR). In fact, for many persons, this contention seems almost obvious. As William Lane Craig has submitted, imagine that there exists a ball that you come across while hiking one day. Naturally, you would suppose there was an origin or reason for the existence of this ball. How would you react then if one of your friends contended that there was no explanation for the ball? It just existed! Obviously, you would not take that claim seriously. Even if the ball was larger (as large as the universe itself), the size of the entity in question would do nothing to constitute believing it existed without sufficient reason.

Despite this common understanding, many atheists have held that the universe does exist inexplicably. It has been their argument that, “…the universe is just there, and that’s all” (Bertrand Russell). Of course, such a statement is a clear negation of the first premise. This rebuttal holds that things can exist inexplicably, and therefore, the principle of sufficient reason is not true. The problem with this belief is that it undermines the entire enterprise of scientific thought. Once a person admits that contingent things (like the universe) can just exist inexplicably, there becomes no reason to explain anything, and there exists no reason to trust the senses or reason itself. Things can merely exist without explanation.

David Hume stated, “If I ask why you believe any particular matter of fact, which you relate, you must tell me some reason; and this reason will be some other fact, connected with it. But as you cannot proceed after this matter, in infinitum, you must at least terminate in some fact, which is present to your memory or senses; or must allow that your belief is entirely without foundation” (An Enquiry Concerning Human Understanding).

Based upon these arguments, it seems it is reasonable to admit that everything which exists has an explanation, but what could these explanations be?

Per this version of the argument, things can either exist for one of two reasons: it exists by the necessity of its nature, or it is from an external cause. Things which fall into the latter category are known as contingent. Philosophically, if something is contingent, then it is not necessarily true or necessarily false. It could be, but it could also fail to be. Examples of things which are contingent are part of the everyday human experience. These things include animals, food, plants, minerals, and even humans themselves. These things do not have to exist but they do. Also, this category includes non-existent entities like unicorns, leprechauns, and Santa Claus (sorry, kids). These things could exist (at least, there exists nothing logically incoherent about these things), but they do not.

Things which fall into the former category are a bit harder to grasp mentally, but these things are that which cannot fail to be. Examples would include numbers. The number “5” cannot be anything other than “5.” Another example would include necessary and absolute truths like, “A triangle has 3 sides.” A triangle cannot cease to have 3 sides, because without this exact number of sides, it would cease to be a triangle.

Although not relevant to the current argument at hand, could there exist things which must fail to exist? Yes, and these things are known as impossible. Examples include logical incoherencies like a married bachelor, a square circle, the shape of the color purple, or the smell of a mathematical equation. These things cannot exist because they are in essence meaningless statements and in some cases blatant contradictions. They are logically incoherent.

Outside of these two alternatives, it is odd to admit anything could exist any other way. As I have argued, things cannot begin to exist while being uncaused (1), and a thing cannot bring itself into existence as I have also argued (2). Therefore, it seems the first premise is substantiated.

Premise 2: If the universe has an explanation of its existence, that explanation is in a necessary being.

Why believe the explanation of the universe lies in a necessary being? Why not contend as David Hume did, “Why may not the material universe be the necessarily existent being?” He goes on to argue, “How can anything, that exists from eternity, have a cause, since that relation implies a priority in time and a beginning of existence?” (Dialogues Concerning Natural Religion, part 9). What is important to remember is that in order for something to exist necessarily it must be both of two things: eternal (it must always have been) and changeless (it cannot be another way).

The eternality of the universe was a long held belief by many scientists until the 20th century when Einstein’s General Theory of Relativity suggested the universe had a beginning. Then, in the 1920’s, Alexander Friedman and George Lemaitre used Einstein’s equations to predict the universe is expanding. Then, in 1929, Edwin Hubble noticed a red shift in the light from stars in distant galaxies, which provided cosmologists the first empirical evidence that the universe is expanding. Since this phenomenon demonstrates that the wavelength of light is being stretched, the conclusion is that the universe itself is expanding or else such an event would not transpire. Next, in the 1960’s, scientists Arno Penzias and Robert Wilson discovered cosmic background radiation which is thermal radiation left over from an event like the Big Bang which suggests such an event did occur. Finally, the Borde-Guth-Vilenkin (BGV) Theorem was presented in 2003, and this theorem for many was the final nail in the coffin of an infinite universe. This theorem suggests that a period of inflation has to have a beginning. Therefore, any expanding universe (like the actual universe) cannot be infinite in the past. This applies independent of quantum theory models of the universe and even applies to the multiverse (if such a thing exists).

Alexander Vilenkin (of the BGV Theorem) has stated, “All the evidence we have says that the universe had a beginning.” But, if the universe did indeed have a beginning, it would be a contingent entity.

Further, there exists no reason to believe the universe is changeless. At the very least, a person could conceive of a possible world in which the subatomic particles of the universe are arranged in a different way. A person’s intuition holds to this belief. As William Lane Craig and J.P. Moreland have argued, “We have, we think we can safely say, a strong intuition of the universe’s contingency. A possible world in which no concrete objects exist certainly seems conceivable. We generally trust our modal intuitions on other matters; if we are to do otherwise with respect to the universe’s contingency, then atheists need to provide some reason for such skepticism…” (Philosophical Foundations for a Christian Worldview, 467-8). If the universe is changeless, then hard determinism follows. Everything is determined, and there would exist no freedom. Human intuition and experience holds otherwise. What is needed is a legitimate reason to accept such a radical claim and yet no philosopher has been able to provide one. If the universe is not changeless, it would be a contingent entity.

What about the second part of the second premise? Why must the explanation of the universe be founded in something necessary? If the explanation is contingent, then that explanation would need an explanation, and this list of contingent things must end in a necessary thing or continue to infinity. The problem with the latter option is that actual infinites lead to logical absurdities. On this view, for every event which transpires, there is always an event before to infinity. An example which helps communicate actual infinites are impossible is Hilbert’s Grand Hotel paradox. Imagine a hotel with an infinite number of rooms that are all full. The rooms are numbered from 1 to infinity. If all the rooms are booked, then no more guests can stay in the hotel, right? Not necessarily, because if a new guest arrives, then all the hotel manager must do is move the guest in room 1 to room 2, the guest in room 2 to room 3, and so on. The guest in room n will be moved to room n+1. After this process takes place, all the rooms are full, but what if another guest arrives? Then the process is repeated. This paradox helps explain the absurdity of an actually infinite number of past events.

As David Hilbert put it, “The infinite is nowhere to be found in reality. It neither exists in nature nor provides a legitimate basis for rational thought…  The role that remains for the infinite to play is solely that of an idea.”

There must exist something necessary from which the universe finds its origins. Why must it be a necessary being? Why not a necessary substance? Back in the middle ages, medieval Muslim theologians wrestled with the idea of whether or not a finite effect could come from an eternal cause. If the explanation of the universe is simply a set of sufficient conditions, or an impersonal substance, and if the explanation is necessary and eternal, then the effect ought to be eternal. If the cause is there, the effect should be there. The effect should be simultaneous with the cause, so if the cause of the universe is eternal, why is not the universe eternal as well? It seems the only way to get around this problem is to deposit that the necessarily existing thing possesses freedom of the will. This idea is simply that despite being eternal, the necessarily existing thing can arbitrarily choose to create. For example, a man sitting down from eternity can freely choose to stand up so long as he has the ability. This reconciliation leads away from the idea of a necessarily existing substance, because impersonal substances do not have freedom of the will.

Therefore, since the universe is not eternal or changeless, an infinite regress is logically absurd, and a necessary substance is insufficient to explain the universe given the universe’s finite nature, what follows is that the explanation of the universe is in a necessarily existing being. Further, by the very nature of the case, this cause would also need to have the power to create, and the intelligence to create a universe, especially if it is fine-tuned for the very existence of said universe (which is a topic for a future blog post).

Premise 3: The universe exists.

I would certainly hope this premise is not controversial.

Premise 4: Therefore, the universe has an explanation of its existence (from 1 and 3).

Based upon premises 1 and 3, it is reasonable to conclude that the universe does have an explanation. As I have already stated, it would be odd to contend that things can exist inexplicably. There exists no justification for this claim. Even more so, it is odd to say that things do have explanations of their existence, but the universe does not. This case is obviously special pleading.

Premise 5: Therefore, the explanation of the universe’s existence is in a necessary being (from 2 and 4).

Based upon premises 2 and 4, the universe does indeed have an explanation of its existence, and that explanation is in a necessary being.

Conclusion: A necessary being (God) exists.

If the universe is indeed founded in a necessary being, then the necessary being must exist in the first place. Therefore, Leibniz’ Contingency Argument gets the reasoner to the conclusion of the existence of God, a being who is uncaused, eternal, changeless, intelligent, powerful, and personal.

“For everything was created by Him, in heaven and on earth, the visible and the invisible, whether thrones or dominions or rulers or authorities– all things have been created through Him and for Him.” – Colossians 1:16


(1): Link here; https://theresidenttheologianblog.wordpress.com/2016/03/02/on-the-existence-of-god-the-kalam-cosmological-argument/

(2): Link here; https://theresidenttheologianblog.wordpress.com/2016/03/15/objections-to-the-kalam-cosmological-argument/

One thought on “Leibniz’ Contingency Argument

  1. Pingback: God vs Science: Understanding Causes – The Resident Theologian

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