Where should a case for God’s existence begin? Admittedly many if not all of the arguments can appear intimidating for those who are unfamiliar. Even the “contingency argument” just sounds complicated. When in fact the argument from contingency is quite possibly the simplest argument for God’s existence; and, in my view, it is appropriately where Christian apologists should begin their case for the existence of God. Let me remind the reader that arguments for the existence of God are cumulative—that is, a diversity of arguments strengthen the conclusion that God exists, and the conclusion does not rest or fall on any individual argument.
Do you think something can come from nothing? By “nothing” I do not mean how many contemporary scientists define it, which is in fact something, but the more obvious notion of the absence of anything. 18th century Christian philosopher, Gottfried Wilhelm Leibniz, certainly believed that something cannot come from nothing. Accordingly, he asked a question that serves as the foundation for his so-called contingency argument: “Why is there something rather than nothing?”
The contingency argument belongs to a family of what are called cosmological arguments, which seek to provide a Sufficient Reason or First Cause of the universe.[1] So one may also refer to this argument as the Leibnizian cosmological argument. The argument sets out to show that everything requires an explanation of its existence. For everything that exists, there is a reason for why it exists. Nothing can be more fundamentally basic in apologetic arguments.
You may be wondering, if everything has an explanation for its existence, then what about God? Leibniz discovered that there are two ways something can exist: Either necessarily or contingently. To exist necessarily is to exist in every possible world; it exists because it has to exist; and it could not have been otherwise! To exist contingently simply means that it is not necessary; it could have not existed. Because it did not have to exist, there must be an external cause of its existence.
The universe exists, so what explains why it exists? Almost no scholar, including skeptical scientists, believe the universe exists necessarily (and those who do believe such posit some non-evidenced theory). The universe therefore must exist contingently. But if it exists contingently, what is its cause? The answer cannot be found within the universe itself, for everything within the universe is also contingent. And it will not suffice to say that the explanation for the universe is found in some prior physical cause, because then we might ask what explains that phenomenon, and onto an infinite regress. Even if there were an infinity of past physical states, the question still remains why there are such physical states at all.[2] Leibniz argued that the only plausible explanation for why the universe exists is that there must be a transcendent, necessary being who brought the universe into existence, called God.
Since God is a necessary being, he does not require a cause. The explanation for why God exists is just simply that he exists necessarily. Skeptics may think this is special pleading. On the contrary, there are a number of things philosophers would argue are also necessary. These would be things like laws of logic or mathematical certainties.
That is the contingency argument in a nutshell. Everything that exists has an explanation for why it exists, either by a necessity of its own nature or in some external cause. And the best explanation for why the universe exists (contingently) is God.[3]
Let me know if anyone needs help understanding the difference between existing necessarily and existing contingently - Christian