A common (abject) objection against theism is that it begs the question. This is especially true of cosmological arguments, as the atheist will argue that it accommodates God into a “set of things that do not begin to exist” without any reason for why we should attribute such a property to Him. In many ways, such an argument does not understand the nature of God in the way it ought to. We tend to think of God as a being among other beings, with the exception that He contains properties like omnipotence and omniscience that are said to be exclusive to Himself. This exclusion is often times not understood by theists themselves, as there’s no reason in their mind for why another being could not posses omniscience while lacking in omnipotence. For some, that is not a concern for so long as that being is not a “maximally great being”, it cannot be God and would necessarily be contingent. There’s truth to this but it concedes too much. It conceives of God as a mere conjunction of properties into one being and often times, merely treats God as comparable to a human person but without our limitations. This is known as theistic personalism, which is flawed for many reasons. For my purposes, I will only focus on one of those reasons.
It is important to recognize that this is not an attack on the ontological argument. If there is a proper metaphysical basis in which to understand those properties, then it can be appropriate to invoke them. However, once one denies Thomism and its notion of divine simplicity, it leave us open to all kinds of misconceptions about God, some of which are unknowingly communicated by atheists themselves. Take, for example, their criticism that it begs the question to argue that God did not begin to exist. While a theistic personalist could technically supply an answer to this, it is nowhere near as effective as a thomistic response. Since the theistic personalist conceives of God as a being composed of distinct properties like omnipotence, omniscience and omnipresence, their intellect is capable of grasping its essence without knowing from its essence whether it is in principle identical to existence or not. While a God with such distinct properties is posited as necessary, it does not explain how those properties entail its necessity. Its necessity is just included in the concept, which to be fair, is proved through arguments like the LCA but if we’re investigating how we define God to be, then it is a good idea to understand why He’d be necessary in principle without subjecting ourselves to contingent proofs like the universe.
This should not be confused with defining God into existence. Instead, we’re seeking to grasp the essence of God in an appropriate manner so as to avoid errors in our understanding of what He would be like if He did exist. The classical theist will assert that the essence of God does not simply happen to be necessary because some contingent fact needs to be explained but instead asserts that He must be metaphysically ultimate as Pure Actuality. The former is substantiated by a matter of fact whereas the latter is substantiated by a proper metaphysical understanding of reality. For something to be pure act, it must have no potential in its being to be anything other than what it is. This stands in sharp contrast with everything else because everything else must be compounded with potency and act either in its composition as form and matter and/or in its composition as essence and existence. If one can grasp a thing’s essence without knowing its existence from that essence, then it must’ve been compounded with existence by something else. If matter is always conjoined with a form, then it is not matter itself that subsists but the form in conjunction with that matter. Thus, matter as such must always have the potential to take on a different form.
In principle, pure act cannot be compounded with such potencies. This entails some interesting conclusions about its nature. First of all, pure act cannot be compounded with existence or it would have the potential to fail to exist. Instead, its essence must be identical to existence in such a way that by merely being as such, it must exist as it is. Second, it cannot be a material substance because it would need to be compounded with form and matter, which is itself subject to potency as explained earlier. Third, it cannot be composed of parts for no individual part is identical to its essence or its existence and therefore, no composition of such parts will explain its existence. For example, if all parts are red and the whole is blue, how can the parts explain its blueness? Therefore, pure act must be simple. Lastly, it cannot be multiplied as this requires an addition to differentiate between Pure Act Y and Pure Act X. Any addition must either be included in its essence or is accidental to its essence. If it is included in the essence, then the addition that differentiates them could remain identical to existence in both cases. However, this entails us to think that Y can become X (and vice versa) once Y actualizes X’s addition. It’s a contradiction for Y to become X and remain identical to existence if Y is no longer in existence because that entails potency. Nor can it be accidental to its essence for that which is accidental may potentially not be. Therefore, there can only be one Pure Act.
This can be taken even further. For Thomism, goodness is convertible with being in the sense that the good is determined by a thing’s nature. Whatever is good has being and whatever is bad is a privation of being. Pure Act is Being itself as it has no potential to be other than what it is and must therefore be goodness itself. No other being is as perfect in goodness, for they are all composed of act and potency. To summarize, we have one immutable, eternal, necessary, immaterial, ultimate, simple, and perfectly good being. This is what we call God and that is only scratching the surface, as much more can be said if one uses the Five Ways and various other theistic arguments to understand His essence. Notice, however, just how much was derived from a simple concept like Pure Act. Anything that is uncaused must be devoid of any potentiality and from this idea, we can arrive at a single being that holds these exclusive properties. While one could reject the metaphysic in which this argument depends on, it is difficult to do so without engaging in nonsense. It should be clear, however, that to ask “What caused God?” is as ridiculous as asking “What actualized Pure Actuality’s potency to exist?”. If such a being does exist, as I think He does, then this is precisely what He ought to be by nature.