Authored by: isaacf.

An article originally written in July 2009 for the Society Of Christian Apologetic Enthusiasts now Rational Theism at http://philapologia.org

The cosmological argument is one of the oldest arguments for the existence of God. It has its roots in the work of the Greek philosophers Aristotle (384–322 BCE) and Plato (427–347 BCE). Today, we have two popular versions of the argument: theKalam and the Leibnizian arguments. Both attempt to show that there must have been a first cause or sufficient reason for the universe to exit. However, one seldom hears of the original cosmological argument as it was made famous by Thomas Aquinas (1225-1274). Aquinas’s argument is handy if one wants to avoid heavy debates on the philosophy of time and the principal of sufficient reason that other cosmological arguments bring to the table.

The simplest statement one can find of Aquinas’s argument is found in his Summa Contra Gentiles:

We see things in the world that can exist and can also not exist. Now everything that can exist has a cause. But one cannot go on ad infinitum in causes… Therefore one must posit something existing of which is necessary. (Summa Contra Gentiles 15.124)

We can see that this argument, rather than focusing solely on cause and effect as Kalam does, or on sufficient reason as the Leibnizian does, attempts to combine the two by examining causal chains and their modal status. David Beck, a modern day defender of the TCA, gives the example of a train. If we visualize a train being pulled, we ask ourselves “What is the cause of the cart in front of us being pulled?” The answer is of course the cart in front of it, but what is pulling that cart? Well the cart in front of it. The problem is that we see that all the carts are dependent on the one in front of it to move, but this cannot go on forever otherwise the carts would never be in motion. We can break the causal chain by positing a being which depends on nothing for its movement; the engine which by its very nature is able to move. This illustration is clearly an analogy for existence. The contingent beings are the carts, and God is the engine: the thing of which by its very nature exists and does not depend upon another thing for its existence.

We can summarize our reasoning thus far in the following way:

P1. A contingent being exists.
P2. What explains this being’s existence must be in a set that contains either only contingent beings or contains at least one necessary (non-contingent) being.
P3. A set that contains only contingent beings cannot cause this contingent being to exist.
C1. Therefore this set contains at least one necessary being.
C2. Therefore a necessary being exists.

Premises one and two are not at question. The third premise is true due to the fact that if there was ever a time when nothing existed, then nothing currently exists, since contingent beings are finite in temporal duration and cannot cause themselves to exist. It follows then that if even one contingent thing exists, whether it be the universe as a whole, a chair, or my best friend Steve, then there exists a necessary entity.

What then can we deduce about then nature of this necessary entity? Firstly, Occam’s Razor eliminates the possibility of there being more then one necessary being, since positing a plurality of beings does not seem to be necessary for the explanation. From this, we can conclude that monotheism is true. Secondly, since this necessary being is the cause of space and time, the necessary being must transcend space and time, and therefore exist non-temporally and non-spatially (at least without the universe). This necessary being must therefore be changeless. The cause must also be immaterial since something can only be timeless if it is unchanging, and something can only be changeless if it is immaterial. It must also be unimaginably powerful, since it created all of space, matter, and time. Finally and most remarkably, such a transcendent cause must be personal, for how else could a timeless cause give rise to a temporal effect (like the universe)?¹ The only entities that we know of which can be timeless and immaterial are minds and abstract objects (numbers, sets, laws, theories, colors, etc). But abstract objects can’t cause anything. Therefore the being which exists, must be an unembodied mind. If the cause were just a mechanically operating set of necessary and sufficient conditions, then the cause could never exist without the effect. If the cause were timelessly present, the the effect would be timelessly present too. The only way for the effect to be timeless and the effect to be in time would be for the cause to be a personal agent with free choice. Thispersonal agent chooses to create an effect in time without any prior determining conditions.

Thus we are brought not only to a transcendent cause of the universe, but to its creator. So, from the Thomistic cosmological argument alone we can may conclude that a personal creator exists, and is uncaused, necessary², unique, beginningless,changeless, timeless, immaterial, very powerful, and personal. From this, it is reasonable to conclude that God exists.”

1. This deviates from Aquinas’s original presentation of the argument and presumes the past duration of the universe to be finite. Though there are good reasons for believing the past duration of the universe to be finite (The Kalam cosmological argument takes this approach), Aquinas’s goal was more modest: his argument is compatible with a universe whose past duration was infinite. However, I wish to extend the force of Aquinas’s argument, and hence I do not assume the eternality of the universe in this essay. [↩]
2. In the factual sense. [↩]