Much has been discussed about the horizontal cosmological argument, also known as the Kalaam Argument. Perhaps its most widely known modern proponent is William Lane Craig. In summary, it says that way back in the beginning, the universe had to have had a first cause. However, the vertical argument is perhaps even more powerful, and is the only one that can defeat strong pantheism.
However, the vertical cosmological argument suffers from an acute case of abstractness, so that its difficult to get a clear, concise explanation of it. Indeed, the argument often takes very different forms when explained by different authors. Here I will attempt an easily understood example.
Let’s say you have found an antique clock. You notice that the hands on the clock are moving. You say to yourself, “Self, I wonder how those hands have come to be moving?” You look closer, and notice a little door on the back of the clock. Upon opening the door, you notice that the hands are attached to a gear. “Aha, I know what is making the hands move. It’s this gear.” But the problem is not solved, for what is making the gear move? You look closer, and notice that the gear is attached to a second gear which is moving the first one. But again, this does not solve the problem, for what is making the second gear move? You keep looking, and discover a lot of gears, each one causing the next one to move. The further you look, the more gears you find, and there are so many, you can’t find the end of them.
Now in this particular clock, you now have a problem, for you can’t find the source of the movement. You might conclude, “I don’t need a first cause of the movement, because I have an infinite number of gears in the chain.” But this can’t work, because an infinite number of gears cannot explain the cause of the movement……pushing back the source of the movement to infinity merely compounds the problem. We must have a current, ongoing cause of the movement. An infinite number of gears that are being moved by another does not provide a source of movement.
It also does no good to say that the movement is not caused, for then you’d have an effect with no cause, which is absurd. There must be a first mover, and this first mover must be anchored, and not being moved by something else (for this would again not answer our problem). The mover must be different than the series of gears. Hence, the unmoved mover, or uncaused cause.
The vertical argument says that there must be a current cause of existence, a current cause of active being. And merely inserting an infinite series of causes does not account for the present cause of active being. There must be a first cause, and that first cause must be uncaused. This is supported biblically in Colossians 1:17, “And He is before all things, and in Him all things consist.” (or have being; are being caused)
Thomas Aquinas presented several variations of the argument, both within his Five Ways and in other places in his Summa Theologica (1.3.4). Part of the reason the Five Ways can be so easily dismissed by modern critics is that they do not grasp Thomas’ perspective on vertical causality, and the critics’ only perspective is a horizontal causality. Other authors that deal with the argument include George Klubertanz in his Introduction to the Philosophy of Being, which has a thorough explanation (p.196), and a much more readable version by Norman Geisler in Christian Apologetics.