We live in an amazing universe. Have you ever wondered why it exists? Why does anything at all exist? Gottfried Leibniz wrote, "The first question which should rightly be asked is: Why is there something rather than nothing?" He came to the conclusion that the explanation is found in God. But is this reasonable? Everything that exists has an explanation of its existence. If the universe has an explanation of its existence, that explanation is God. The universe exists. From these it follows logically that the explanation of the universe's existence is God. The logic of this argument is airtight. If the three premises are true, the conclusion is unavoidable. But are they more plausibly true than false? The third premise is undeniable for anyone seeking truth. But what about the first premise? Why not say, "The universe is just there, and that's all"? No explanation needed! End of discussion! Imagine you and a friend are hiking in the woods and come across a shiny sphere lying on the ground. You would naturally wonder how it came to be there. And you'd think it odd if your friend said, "There's no reason or explanation for it. Stop wondering. It just IS!" And if the ball were larger it would still require an explanation. In fact, if the ball were the size of the universe, the change in its size wouldn't remove the need for an explanation. Indeed, curiosity about the existence of the universe seems scientific - and intuitive! Someone might say: "If everything that exists needs an explanation, what about God? Doesn't he need an explanation? And if God doesn't need an explanation, then why does the universe need an explanation? To address this, Leibniz makes a key distinction between things that exist NECESSARILY and things that exist CONTINGENTLY. Things that exist NECESSARILY exist by necessity of their own nature. It's impossible for them NOT to exist. Many mathematicians think that abstract objects like numbers and sets exist like this. They're not caused to exist by something else; they just exist by necessity of their own nature. Things that exist CONTINGENTLY are caused to exist by something else. Most of the things we're familiar with exist contingently. They don't HAVE to exist. They only exist because something else caused them to exist. If your parents had never met, you wouldn't exist! There's no reason to think the world around us HAD to exist. If the universe had developed differently, there might have been no stars or planets. It's logically possible that the whole universe might not have existed. It doesn't exist necessarily, it exists contingently. If the universe might NOT have existed, why DOES it exist? The only adequate explanation for the existence of a contingent universe is that its existence rests on a non-contingent being - something that cannot not exist, because of the necessity of its own nature. It would exist no matter what! So "Everything that exists has an explanation of its existence"..."either in the necessity of its own nature, or in an external cause." But what about our second premise? Is it reasonable to call the explanation of the universe...God? Well, what is the universe? It's all of space-time reality, including all matter and energy. It follows that if the universe has a cause of its existence, that cause cannot be part of the universe - it must be non-physical and immaterial - beyond space and time. The list of entities that could possibly fit this description is fairly short - and abstract objects cannot cause anything. Leibniz' Contingency Argument shows that the explanation for the existence of the universe can be found only in the existence of God. Or, if you prefer not to use the term "God," you may simply call him: "The Extremely Powerful, Uncaused, Necessarily Existing, Non-Contingent, Non-Physical, Immaterial, Eternal Being Who Created the Entire Universe...And Everything In It."