The argument from contingency

0. Introduction

The ‘argument from contingency’ is a version of the cosmological argument. It has various forms, and historians of philosophy trace it as far back as Avicenna in the 10th century. It is one of Aquinas’ five proofs, and is part of the repertoire of the classical apologetical method. I have an objection that I will explain here. It is probably not new (as it is such an old argument), but I like it, so I want to spell it out.

1. The argument

There are various ways to phrase the argument, and there will doubtless be ways to spell it out that avoid my particular objection, but this is a classic way of presenting the argument.

The driving idea is that the universe, if its existence is contingent (i.e. if its existence is neither necessary nor impossible), requires an explanation. Contingent things cannot just exist with no reason for them. Take this pillow. Its existence is contingent, in that it could have not existed. The fact that it does exist is a fact which can be explained (at least in principle); there is some answer to the question ‘why does this pillow exist?’. One way of thinking about the explanation for its existence is in terms of the causal conditions that brought it into existence. So perhaps it was made in a factory, by some Chinese pillow-manufacturer or whatever. There is some causal story we could tell which would explain why this pillow exists. Not only that, but it has to have some story or other like this which explains its existence. If it wasn’t made in a Chinese factory, then it was made somehow, somewhere. It couldn’t be that it just was. A thing which is contingent, whose existence is neither necessary nor impossible, but which just existed for no reason, is (so the argument goes) itself impossible. Contingent things, like pillows, porcupines, pineapples, or people, etc, are contingent, and they all have explanations for their existence. Sometimes, this principle is called the ‘principle of sufficient reason’.

But consider something whose existence is necessary; something which couldn’t not exist.  Let’s say that the number 9 exists (it doesn’t matter if you don’t like this example, just plug in your own favourite example of something which necessarily exists). If the number 9 exists, its existence is not the sort of thing that could have failed to be the case. No matter what happens in the world, no matter the coming or goings of physical things, the existence of the number 9 is completely independent of it. Thus, there could be no causal explanation for the number 9, as it exists over and above the causal chains that contingent things exist within the world. It doesn’t make sense to explain why something exists, if it couldn’t not exist. Unlike contingent things, like me or my pillow, there is no answer to the question: ‘why does the number 9 exist?’.

Given this distinction between contingent things, whose existence requires explanation, and necessary things, whose existence doesn’t require explanation, we seem to be faced with a trilemma. That is, there seem to be only three possible options. The options seem to be:

1. Each contingent thing has as its explanation another contingent thing. So my pillow was made by a person, who was made by another person, and ultimately life was created by contingent physical processes, which themselves were contingent outcomes of contingent events. The chain of contingent things stretches back forever, with each contingent thing having a contingent explanatory thing that it depends on for its existence.
2. Most contingent things have as their explanation other contingent things, but the chain of dependency doesn’t go backwards forever; rather, it terminates at some point. The point at which the chain terminates is itself a contingently existing thing. Perhaps there was a burst of energy at the big bang, which was itself a contingently existing thing, but (contra the principle of sufficient reason) the existence of this thing has no explanation whatsoever. It just happened for no reason.
3. Most contingent things have as their explanation other contingent things, but the chain of dependency doesn’t go backwards forever; rather, it terminates at some point. The point at which the chain terminates is itself a necessarily existing thing. This necessarily existing thing is the ultimate cause and explanation for the existence of all of the contingently existing things. Let’s call this first mover, this necessarily exiting thing, ‘God’.

It seems that these are the only possible options, and so all one has to do to prove that God exists is to rule out the first two options. Here, the principle of sufficient reason does most of the heavy lifting. Take option 2. The idea of something contingent just happening for no reason is supposed to be impossible. Contingent things don’t just happen. Imagine you came across a pattern in the sand while walking along the beach that read ‘Hello’. This is obviously the sort of thing that could have not existed, and so it is a contingently existing thing. It is also the sort of thing that it would make sense to ask ‘why does this exist?’, and there will be an answer to this question. Someone probably drew the lines in the  sand with a stick. It may have happened by some very unlikely process of the wind working in just the right way so as to make the letters appear in the sand. However it happened though, there is some explanation for it. It couldn’t be that it exists but without an explanation. It would be like thinking that each domino fell because the previous one fell into it, but that at some point a domino just falls over without anything falling into it, for no reason.

Similar reasoning applies to option 1. Obviously, in this case (unlike in option 2) there is no contingently existing thing that has no explanation for its existence; each contingently existing thing has a contingently existing thing as the explanation for its existence. So on this picture, each thing has an explanation. However, there is no explanation for why the whole sequence of contingent things exists. Where did it come from, ultimately? As the infinite chain of contingent things recedes off into the distance, one is left with the feeling that this infinite bunch of contingency is just as strange as the brute contingent fact that we found so strange in option 2. If the dominos each fall because the previous one fell into it, and this goes on forever without a starting point, it is ultimately a complete mystery why any of them started to fall over at all.

The last option then is the only one that could have any hope of offering any explanation for the contingency of the world. On this option, the necessarily existing starting point caused the first contingent thing to exist; it pushed the first cosmic domino over. As it is not a contingently existing thing, it doesn’t require an explanation for it’s own existence, so the termination point of the chain is not arbitrary, as on option 2. Thus we seem to have found the only option that is acceptable, according to the principle of sufficient reason. There are contingently existing things in the world (like pillows), so there must have been a necessarily existing thing that caused them to come into being.

2. Some Responses 

So how should someone respond to this argument? One could of course reject the idea that contingently existing things need an explanation. This would allow one to embrace option 2. The problem with this is supposed to be that the idea that contingently existing things require explanations is a fundamental assumption to science, and to any rational understanding of the world. If things could just exist without explanation, then there would be no way of knowing with any given contingent thing whether it was one of those things. One would always have to wrestle with the option that the given phenomenon, such as the spread of the disease across the population, or the fact that the bowling ball falls to the earth with such and such velocity, could just be a brute fact with no explanation. Science, it seems, requires that option 2 is false.

One could accept the idea that contingently existing things require an explanation, but reject the idea that there are contingently existing things at all. Maybe there is just the appearance of contingency, whereas in reality everything is necessary. The cost of this view is that it seems intuitively very obvious that most things are only contingently existing. Most of them could not exist. It is obviously possible that I could have not existed. In fact, if you consider how many contingent things are required for my existence, my parents meeting, their parents meeting, their parents meeting, etc, my existence should be almost impossibly unlikely. I quite obviously do not exist necessarily. Saying that everything which exists does so necessarily seems very hard to maintain.

Lastly, one could try to opt for option 1, where each domino falls because of the previous one, in a never ending sequence back into infinity. Here, the well-rehersed absurdities resultant from infinite sequences come into play. Imagine someone who was counting up from minus-infinity. As you come across him you hear him saying ‘…minus 3, minus 2, minus 1, 0 …’. The idea that he has come to 0 at the precise moment that you come across him seems to have no explanation. Why had he not arrived at this point before? Why does he not come to this point tomorrow instead? After all, it must have taken him an infinite amount of time for him to get here, whether he got here yesterday, today or tomorrow. There can be no explanation for one over the other. Thus, we seem to be back in the boat of option 2.

3. My response

My response is not to take any of these options. I do not really offer a solution to the problem as such. My tactic is to point out that option 3 is no better off than options 1 or 2. Here is how I see the problem. On this option it is God, the necessarily existing thing, that set the contingent sequence of things off. But when he did so, what was the nature of the choice? Specifically, was there something in virtue of which God made the choice to create this sequence of contingent things rather than another sequence, or rather than no sequence at all? There seem to be two options here:

i) Yes, there was something in virtue of which God made this choice.

ii) No, there was nothing in virtue of which God made this choice.

Note, that we are not asking whether there is something that explains God’s existence. We do not need to say that God is not necessary, or that necessary things require explanations. Rather, we are asking whether God’s choice is the sort of thing that has an explanation.

Let’s explore option i). On this view, God made his choice because of something; there is something which explains his choice. Familiar candidates for such a thing might include his nature (perhaps he is by nature something which wants to be in a loving relationship with certain contingent things), or God’s nature plus the nature of this world (perhaps God always wants the best thing, and perhaps this is the best of all possible worlds). On any view like this, it seems that God’s choice is not completely free. In some sense he has to make this choice, as a result of his nature. If that is right, then the existence of the world, and all the apparently contingent things in it, is in fact necessary; they had to happen, and couldn’t have not happened. The existence of the world is as necessary as the existence of the first mover. Neither could happen without the other.

Let’s look at option ii). On this view, there is nothing in virtue of which God made the world. He chose to make this world completely free of any determining factor. He wasn’t dictated by his nature, or by the nature of the world. He could have made any world just as easily as this. On this view, there is nothing which explains why he made this world rather than another, or rather than none at all. On this world, the existence of the universe is indeed contingent, but also without explanation, which violates the principle of sufficient reason after all.

4. Conclusion

Thus, it seems that the third option in our original trilemma really has nothing to offer over and above the first two. If the chain of contingent things terminates in a necessarily existing thing, then either the existence of the world is itself necessary and thus requiring no explanation, or contingent but itself without an explanation.