6. Evidence for God's existence - The Kalam Cosmological Argument

There's a philosophical line of evidence for the beginning of the universe. This line of evidence is so rationally inescapable that some consider it the strongest argument of all. It's called the Kalam (from the Arabic word for "eternal") Cosmological Argument, and it goes like this:

To grasp this argument, see the timeline up next, marked in segments of days. The further left you go, the further back in history you go. Now, assume for a moment that this line extends to the left indefinitely, so that you can't see if or where it begins. But as you look to the right you can see the end of the line because the last segment of the line represents today. Tomorrow isn't here yet, but when it gets here, we'll add one more segment (i.e., a day) to the right end of the line. Now, here's how this proves that time had a beginning: since the line certainly ends on the right, the timeline cannot be infinite because something that is infinite has no end.

Moreover, you can't add anything to something that is infinite, but tomorrow we will add another day to our timeline. So, our timeline is undeniably finite. Let's consider this argument from a different angle. If there were an infinite number of days before today, then today would never have arrived. But here we are! So, there must have been only a finite number of days before today. In other words, even though we may not be able to see, as we look to the left, where the line begins, we know it had to begin at some point because only a finite amount of time could be passed for today to arrive. You can't traverse an infinite number of days. Thus, time must have had a beginning. This can be visualized as a railway train. Each car is being pulled by the car in front of it. The “cause” of movement for any car is the next car ahead. However, if the train were extended forward infinitely, how could it be moving? If the train has an unending succession of cars, then there would be nothing providing force to move the cars. At some point, there must be an engine— something that pulls but is not itself being pulled.

Causes and effects can be imagined the same way: for causality to exist, it must begin, and that requires a single un-caused cause. Some may say that infinite numbers can exist, so why can't infinite days? Because there's a difference between an abstract infinite series and a concrete one. The one is purely theoretical, the other is actual. Mathematically, we can conceive of an infinite number of days, but actually we could never count or live an infinite number of days. You can conceive of an infinite number of mathematical points between two bookends on a shelf, but you could not fit an infinite number of books between them. That's the difference between an abstract and a concrete. Therefore, we conclude with the scientific and philosophical arguments that the universe had a definite beginning and it's first cause is something that itself is outside the time-space constraints. That Eternal first cause is God.