One of the things that thinkers have used to separate God from everything else is the fact that He is what you would call a necessary being. He is the necessary start to a chain of events that we see in existence today. Physicist Stephen Hawking describes an exchange that underlines why a beginning point is important in his book A Brief History of Time:
A well-known scientist (some say it was Bertrand Russell) once gave a public lecture on astronomy. He described how the earth orbits around the sun and how the sun, in turn, orbits around the center of a vast collection of stars called our galaxy. At the end of the lecture, a little old lady at the back of the room got up and said: "What you have told us is rubbish. The world is really a flat plate supported on the back of a giant tortoise." The scientist gave a superior smile before replying, "What is the tortoise standing on?" "You're very clever, young man, very clever", said the old lady. "But it's turtles all the way down!"1As you can see, the little old lady never really gave an answer that would explain anything. The line of turtles must stop somewhere, since they need to sit atop something to be held up themselves. Another example is the idea of origins. If I were to ask how it was that you came to be, you might respond by explaining how your parents met, were married and conceived you. " But," I may continue, " That’s just one link tin the chain. They had to come from somewhere — where did THEY come from?" " From their parents," you counter. "But what about them?" You can see how this quickly devolves into meaninglessness. Such responses to questions about the universe (and our own existence) are known as an infinite regress. When you try to explain the origin of something by adding one more link to the end, it doesn't help much, since you've merely moved the question back to "but where did that come from?"
We somehow need a necessary condition to begin our understanding of everything. We need a floor for our turtles to start piling up on, if you will.2 This is what we mean when we talk of a necessary being. If there is a God, we would find that He is the beginning of the effects which we see around us. If there is not a God, then something else must be the initial condition — the start of this whole universe and its attributes. Whatever the initial condition is, it must have some very specific qualities. That means that whatever answer someone offers, they must show that such an answer is capable of meeting these conditions.
Below is a short video where I note that the beginning of the universe must be either caused by God or by nothing at all. Of the two, I think God makes infinitely more sense.
2. I use this phrase only for its illustrative purposes. If there is a floor, it is of course obvious that the turtles in the above example are unnecessary. To extend the analogy, the Earth could merely be resting on the floor with no turtles or possibly one turtle walking across that floor giving it movement. The main idea is that since a floor is required in all cases, the turtles can be removed and none of the explanatory power is lost, which demonstrates how the stack of turtles really are no help in explaining anything.
Image courtesy Design Alex Mittelmann, Coldcreation. Licensed under CC BY-SA 3.0 via Wikimedia Commons.