Does God exist? This is one of life’s most central questions. Atheists respond with a clear and resounding “No.” Agnostics assert the answer is more ambiguous, claiming it is better to say, “I don’t know,” than give a simple “Yes” or “No” response.

Throughout history, a number of important arguments have been proposed to provide evidence for God’s existence, including moral arguments, ontological arguments, experiential/existential arguments, and cosmological arguments, just to name a few. Although intellectually challenging, I believe one of the best cosmological arguments is the Kalam Cosmological Argument.

The Universe: Does something exist?

The argument begins by recognizing that the universe exists, and that it does so in real space and time. Claiming something, rather than nothing, exists seems reasonable, for if an individual can claim that there is nothing, by the very nature of his or her claim, there must be something in order for the concept of nothing to be contemplated at all. To say nothing exists requires that one claiming non‑existence actually exists to make the claim in the first place. We therefore conclude that we exist and that consequently something really does exist.

The Universe: Did it have a beginning or not?

The next logical question concerning the universe must be, did the universe have a beginning or not? This has been a hotly debated issue during the last few years, especially among the scientific community. The discovery of the stellar “red shift” made it clear that the galaxies were moving away from each other. It was logically extrapolated back that there was a point where all the motion of the galaxies originated in a “big bang,” if you will. All the astronomical data coming in at this point confirms this type of origin for the universe, but most scientists have been extremely evasive about and uncomfortable with the implications of these observations. Why? It flies in the face of a universe without a beginning. It comes dangerously close to the precipice of needing some sort of definite and finite origin for the universe. It must have had a beginning!

Actual and Potential Infinites

For the argument to work, we must now distinguish between the mathematical concepts of actual infinites and potential infinites. Now, stay with me, because this can get very difficult to grasp.

Actual infinites are just that, actually infinite sets of events or numbers. For example, if I have an actually infinite set of whole numbers, the even numbers in the set are equal to the total number of numbers (odd or even) in the set. In addition, actual infinite sets have no beginning or end. If you really think about it, this is illogical and impossible. How, for example, can all the even numbers in the set be equal to all the numbers—both odd and even—in the set? Logically, all even numbers should contain only half the set of numbers, but in actually infinite sets, all the even numbers are equal to the total number of numbers in the set. It is a logical impossibility. That is why actually infinite sets are only mathematical concepts. They may be “useful fictions” in mathematical models and theories, but they do not and cannot exist in our space‑time reality, for they represent illogical unreal and ideas.

Potential infinites, on the other hand, all have a starting point. They are potentially infinite because they can go on indefinitely, but they can never become actually infinite because an actual infinite set by its very nature is not real and has no past events or future events that could occur in the space-time continuum. With an actually infinite set, all the possible events that could occur would have already happened, so to speak. Yet we see in our own universe, that both historical and future events have occurred and will continue to occur. Therefore, the universe we live in could not possibly be actually infinite. It is only potentially infinite.

It does not matter to this argument if the universe has several “beginnings” because there cannot be an actually infinite number of beginnings to go back through. This situation cannot exist in reality, and we know that the universe does exist and that it does have a past and an unfolding future, both features that only exist in a potentially infinite universe that has a definite beginning point. And as was stated above, a potentially infinite universe can never become an actually infinite universe in the space‑time continuum.

Therefore, it seems most reasonable to conclude that, like all potentially infinite sets, the universe had a beginning. Once we get to this point (and understand it!) the rest of the Kalam argument is relatively simple.

Was the beginning caused or uncaused?

To move from a universe that has a beginning, we must then determine if that beginning was caused or uncaused. Everything we know about life and the cosmos suggests that existence and change have causes.

Quantum and chaos theoretical physics has recently sought to find uncaused causes in subatomic theory, but all they have demonstrated is that not every subatomic event has a measurable or predictable cause due to uncertainty. While interpretations of quantum physics is still very much in debate, even if events are apparently uncaused, this does not mean that they are actually uncaused. It merely means we do not know their causes because we do not have the technical ability to properly measure or observe them.

With all of this said, every sound observation of the real world we live in yields the same conclusion: events in space and time have causes. Therefore, it is most reasonable to conclude that the beginning of the universe, as a space-time event, was a caused event, and that this event was caused by something that in and of itself is uncaused. As Thomas Aquinas put it, it is the uncaused (NOT the self‑caused, which is a contradiction) cause of all subsequent contingent events.

Was the cause personal or impersonal?

The next question is this, “Was the cause of the universe a personal cause—a being with intentions and the ability to make choices, or an impersonal cause?” To claim the cause was impersonal is a very difficult premise to defend because it assumes that somehow in the state ontologically prior (for without space‑time, it cannot be temporally prior as we understand time) to the beginning of the universe, certain elements for the creation of the universe somehow existed and then converged at a point where conditions resulted in and caused a created order to emerge.

Such a situation is illogical because outside of space‑time, no events or changes can possibly occur without an initiation of some sort, without some sort of purposeful choice. Something or someone had to bring about the necessary conditions to produce a new reality. It is clearly more reasonable to conclude that the event of creation was personal, made by a being with a will and intentions who could choose at a specific point ontologically prior to the beginning of the universe when time, space, and all of creation would come into being. Otherwise, no basic change in the state of eternality could take place to cause a creation to occur.

Who is this personal being?

It is important to note here that while we have reached the point of saying that the universe exists and had a personally caused beginning by a powerful uncaused “causer,” we have still not found the God of the Bible. We can say some additional things about the character of this uncaused cause, like, for example, that it must be infinite as well as extremely intelligent. But this still does not bring us to the triune God of Christianity. What is needed is some type of sensible, reliable revelatory information about this Creator. I believe this is provided for us through the words and ministry of Jesus Christ, the Word made flesh, as well as the Spirit-inspired word of God, the Bible. Here we have the clearest and most reliable guide for discovering how to know and interact to this infinite, intelligent, powerful, and personal Creator.

Does God exist? He not only exists, He offers a relationship with all who passionately seek to find Him. As God promises in Jeremiah 29:13, “You will seek me and find me, when you seek me with all your heart.” That’s a passion worth pursuing with all passion!