Unlike the Kalam cosmological argument that requires you to hold that the universe had a beginning to reach the conclusion that God exists, the argument for contingency claims to prove the existence of God even if the universe is infinitely old; instead of arguing from the need for a first-cause for the universe, it argues from the need for an explanation for why the universe even exists.
Before going into the argument, however, it is important that I define a couple of terms that are essential to it. We will then go over the argument itself, before examining it premise-by-premise to
- Contingent thing: A contingent thing is something that exists, but does not have to exist. It is possible to conceive of the thing as not existing, and/or another thing existing in its place.
- Necessary thing: A necessary thing is something that must exist. It is not possible to conceive of the thing as not existing, and/or another thing existing in its place.
A form of the argument can be stated as follows:
- Everything that exists is either necessary or contingent.
- There is an explanation for the existence of every thing, either provided by its own nature or by some other thing.
- The existence of a contingent thing cannot be explained by its own nature.
- The existence of a contingent thing must be explained by some other thing. (from 2 and 3)
- The collection of all contingent things is itself contingent.
- The existence of the collection of all contingent things must be explained by some other thing. (from 4,5)
- The thing that explains the existence of the collection of all contingent things cannot be a contingent thing.
- The thing that explains the existence of the collection of all contingent things must be a necessary thing. (from 1 and 7)
- Any contingent thing or set of contingent things within the collection of all contingent things is ultimately explained by a necessary thing.
- The universe is a set of contingent things.
- The universe is ultimately explained by a necessary thing. (from 9,10)
- This necessary thing must be spaceless, timeless, and non-material. (from 11)
- This necessary thing must be God. (from 12)
- God exists.
The Premises Examined
Premise 1: Everything that exists is either necessary or contingent.
This premise is generally taken to be self-evident. We can know for certain that there are things that exist, but could possibly have not existed, and the only alternative to this would be to have a set of things that exist, and could not have not existed in any possible world. While you might not be able to think of a case of the latter off the top of your head, this argument is meant to show you that there must be at least one such thing.
Premise 2: There is an explanation for the existence of every thing, either provided by its own nature or by some other thing.
Better known as the Principle of Sufficient Reason (PSR), this is the most controversial premise of the argument. We shall consider objections against it at a later point in the article, but for now, let us consider how one could make a positive case for it.
By stating that everything that exists must have a reason or explanation for its existence, the proponent of the PSR is asserting that there is no such thing as a brute fact (or a fact that has no explanation but just is). While there is no deductive proof that can conclusively demonstrate the truth of the PSR, its proponents can argue that we have no good reason to reject it and every reason to hold that it is true because it is indispensable to every other arena of our life. As a matter of fact, the very word ‘why’, the use of which is considered good practice in the sciences and in other fields of study concerned with pursuing the truth of the matter, is an affirmation of the truth of the PSR. The atheist or agnostic would be committing the fallacy of special pleading by affirming the PSR’s truth in every other aspect of their life but denying it without good reason in the case of the universe’s existence.
That said, a few atheists think they have good reason to reject the PSR for the universe’s existence. I will outline their view in the section dealing with objections to the argument. If their objection succeeds, Premise 2 will have been shown to be false in the case of the universe, rendering the argument unsound.
Premise 3: The existence of a contingent thing cannot be explained by its own nature.
The very definition of a contingent thing is that it exists, but does not have to exist; it could be conceived of as not existing. Therefore, it is not within the nature of a contingent thing to exist. Hence, the existence of a contingent thing cannot be explained by its own nature.
Premise 4: The existence of a contingent thing must be explained by some other thing.
This follows from Premise 2 and Premise 3. If a contingent thing’s nature does not explain its existence, some other thing must explain why it exists, given that everything that exists must have an explanation.
Premise 5: The collection of all contingent things is itself contingent.
This is the second-most controversial premise in the argument, and we shall consider a serious objection against this premise when we discuss the objections against this argument. For now, let us consider a positive case for this premise.
Say we have a thing ‘A’ that is contingent, and thus it must be explained by some other thing (Premise 4). Let’s say A is explained by ‘B’, which is also a contingent thing. And B is explained by ‘C’, which also happens to be a contingent thing, and so on. Assume we follow this chain of explanations down to the last contingent thing that exists, so that we can say that we’ve gone through the entire set of all contingent things. Each of the things that exist within this set do not have to exist; all of them could be conceived of as not existing, so that the set itself could possibly not exist. Hence, the set or collection of all contingent things is itself contingent.
A very serious objection that can be raised against this premise is that it commits the fallacy of composition. We shall examine this in a later part of this article.
Premise 6: The existence of the collection of all contingent things must be explained by some other thing.
Once again, if one accepts all the previous premises, this premise follows. The collection of all contingent things is itself contingent, therefore its existence cannot be explained by its own nature. Thus, its existence must be explained by some other thing.
Premise 7: The thing that explains the existence of the collection of all contingent things cannot be a contingent thing.
From the previous premise, we know that the existence of the collection of all contingent things must be explained by some other thing because it cannot explain its own existence. But this ‘other thing’ cannot be a contingent thing, because if it were, it would become part of the collection of all contingent things, and it does not really provide an explanation for why the collection exists.
Thus, the existence of the collection of all contingent things cannot be explained by yet another contingent thing.
Premise 8: The thing that explains the existence of the collection of all contingent things must be a necessary thing.
If everything that exists is necessary or contingent, and if the explanation of the existence of the collection of all contingent things cannot itself be contingent, then it must be necessary.
Premise 9: Any contingent thing or set of contingent things within the collection of all contingent things is ultimately explained by a necessary thing.
I alluded to this in Premise 5. Remember, if the existence of every contingent thing within the collection of contingent things was explained by another contingent thing within that collection, we do not have a real explanation or an ultimate explanation. We have merely pushed the problem one step further. Instead, if we do find an explanation for the existence of the collection of all contingent things, this explanation will be the ultimate explanation of the individual contingent things or sets of contingent things within the entire collection, regardless of how many intermediate contingent explanations might be involved.
Premise 10: The universe is a set of contingent things within the collection of all contingent things.
We know that objects within the universe are contingent; they exist, but could possibly not exist. With what we know about the universe itself, we know that it could possibly have not existed. Therefore, the universe is a contingent thing or at least a set of contingent things within the collection of all contingent things.
Note that while some might go so far as to say that the universe is the collection of all contingent things, I’m not suggesting that. It’s possible to leave open the possibility of other contingent things existing outside the universe (such as other universes) without it affecting the argument in any way.
Premise 11: The universe is ultimately explained by a necessary thing.
This follows from premises 9 and 10.
Premise 12: This necessary thing must be spaceless, timeless, and non-material.
A not-so-controversial premise, it states that if this necessary thing that explains the universe is outside the universe and outside the collection of all contingent things, then it must not be made of space, time, and matter, the things that our universe is made of.
Premise 13: This necessary thing must be God.
This is yet another controversial premise. Thomist philosophers like Edward Feser argue that for this thing to be necessary, it must not have any potentialities and thus must be pure actuality; otherwise it would be contingent on something having to actualize these potentialities. Similarly, for it to be necessary, it must be simple and without parts, because otherwise it would be contingent on something having to combine these parts and continue keeping them together. Furthermore, it is timeless (premise 12) and therefore changeless (or immutable), immaterial (premise 12) and therefore disembodied, and spaceless (premise 12). These are attributes that only the being described by the classical conception of God in the Abrahamic faiths possesses, hence the advocate of this argument concludes that this necessary being must be God.
From these premises, the advocate of this argument infers that God exists.
1. The Fallacy of Composition
The fallacy of composition involves taking one or more characteristics of the constituent parts of a whole and inferring that because the parts possess this characteristic, necessarily the whole must also have this characteristic. An example would involve me saying the following, “This laptop is made up of microscopic atoms. Therefore, this laptop is microscopic.”
Critics of the contingency argument often attack the premise that says that the set of all contingent things is itself contingent commits the fallacy of composition. Advocates will point out that the fallacy of composition does not apply across the board; there are cases where inferring from the part to the whole is legitimate. For example, if every brick on the outside of my house is red, it is safe to conclude that the outside of my house is red. As I explained in Premise 5, we are inferring that the set of all contingent things is itself contingent because even after considering every object in that set as being explained by another object within it, we still have no ultimate explanation for that chain of contingent explanations that we have created, explaining why it exists when it was entirely possible for it not to exist or to exist differently.
2. A Necessary Universe?
This is a very good objection that an atheist can raise. They might ask, why can’t the universe exist in a manner that is necessary. One response to this would be the one that philosopher William Lane Craig gave to this objection, which is to say that the universe cannot be necessary because it is very easy to conceive of a totally different set of things existing as the ‘universe’ rather than the ones that are in it now; this goes to show that the universe isn’t the way it is out of necessity, or it doesn’t have to exist the way that it does.
And you might think, “But I can easily conceive of a world in which God doesn’t exist. Did I just make God contingent?” Not at all, because the way we’ve defined God, He is a necessary thing. Sure, if you think of God as some kind of cosmic Santa Claus (as some Christians and most atheists happen to think of Him), yes, He would be contingent. But if you think of Him as being the purely actual, simple, non-composite, spaceless, timeless, immaterial explanation for why there is something rather than nothing, it’s impossible to conceive of Him as not existing.
3. Only One Necessary Thing?
But why should there be only one necessary thing? Why can’t there be two or more necessary things that serve as the joint explanation for the universe’s existence?
Imagine that there are two necessary beings, NB1 and NB2, both having all the characteristics we spoke of above, including being pure actuality. To consider them as two distinct things, there must be something, either perfection or privation, that distinguishes them. But a pure actuality is one that has no privations, so both of them cannot be necessary beings. And since a necessary thing must be a pure actuality, we must conclude that there is only one necessary being.
The atheist could, however, find a way to deny the Aristotelian act-potency distinction. I’m not aware of any such way, but would love to hear if you know of any in the comments below.
4. Against the Principle of Sufficient Reason
Several arguments have been raised against the PSR. One can argue that the truth of the Principle of Sufficient Reason cannot be demonstrated through an argument, neither is it analytic. Others point out that we can conceive of things just popping into existence by chance and so on, hence the PSR is not necessarily true.
For a more thorough argument against PSR, take a look at this essay by William Rowe.
In response, theist philosophers or proponents of the PSR can said that the fact that it cannot be proved is not necessarily because it is questionable; it may very well because it’s obvious, just like the laws of logic are obvious. They further argue that one can prove the truth of the PSR via a reductio ad absurdum, for its denial implies all sorts of skepticism that deniers of the PSR do not hold to be true.
All in all, the PSR is arguably the most controversial premise in the argument. On a more personal level, I think it is up to the atheist to explain why they generally treat the PSR as true except when it comes to the universe and so on, and I’ll be glad to hear from you in the comments if you think that I’m misrepresenting your views in any form.
5. Explanation for God?
If everything that exists must have an explanation, you might ask, why doesn’t God have an explanation for His existence?
The argument does not say that God does not have an explanation for His existence. Rather, it argues that the explanation of God’s existence is the very fact that He must exist because contingent things exist and need a necessary thing to explain their existence. In other words, the explanation for God’s existence is in His very nature. I’ve seen this make many atheists uncomfortable and respond with, “But you’re just defining God into existence!” But am I? We’ve didn’t start from saying that a necessary being exists and therefore a God exists. We started from the existence of contingent things, from which we inferred the need for a necessary thing, and we showed how that necessary thing must have the characteristics that happen to be identical to those of what classical theists call ‘God’.
6. Not Necessarily the Judeo-Christian God/Most Christians Believe in a Cosmic Santa Claus, Not the God of This Argument
Let me consider the second possible objection first. Whether or not most Christians believe in the God described by the contingency argument is irrelevant; all the Christians in the world could believe in a cosmic Santa Claus, but the necessary God of the contingency argument would exist nonetheless. Secondly, a whole set of Christians and Jews and Muslims, generally called ‘classical theists’, believe in exactly this sort of God with exactly these attributes. There are debates within Christianity between classical theism and another school called theistic personalism, but personalism is a far more recent phenomenon in philosophy.
Moving to the first part of the objection, yes, it is true that this argument does not describe all the attributes of the Judeo-Christian God as described in the Bible, such as His being a Trinity or something else, but the argument is rarely used for that purpose. It is generally used to demonstrate that theism is true or at least rational, and that atheism is incapable of explaining the existence of contingent things without falling into an infinite regress. It leaves you open to at least three religions, namely Christianity, Judaism, and Islam, and you have to test the claims of each of these religions to see which one of them got the other aspects of reality right; for instance, you will have to independently test the credibility of the Prophet Muhammad and his prophecies, or investigate whether or not there is any evidence for Jesus existing and doing the sorts of things that are attributed to Him.
That concludes our discussion of the argument from contingency. Keep an eye out for my next post.