That is because God alone is the Absolutely Real, and what they call upon other than Him is unreal, and God alone is the Sublime, the Exalted.

Qur’an 31:30

The most truthful statement a poet ever uttered is the statement of Labīd: “Verily, everything other than God is unreal.”

Prophet Muĥammad ﷺ, Śaĥīĥ al-Bukhārī

Monotheism is to singularize the Eternal and to regard Him as absolutely distinct from everything temporal.

Imam al-Junayd (d. 298/911), Muslim scholar and mystic

The German philosopher Immanuel Kant (d. 1804) famously divided arguments for the existence of God into three main types: ontological, cosmological, and teleological. The latter two categories begin with a premise known as a posteriori—that is, based on experience or empirical data. Ontological arguments seek to demonstrate the existence of God using a priori deduction, or deduction from a purely conceptual analysis without recourse to any empirical observation. A valid ontological argument would be akin to sound mathematics and hence rationally undeniable. In the history of Western philosophy, arguments of this kind were attempted by figures such as Anselm of Canterbury (d. 1109) and René Descartes (d. 1650), although their arguments were received with much criticism and to this day remain highly contentious. Their ontological arguments begin with a certain conception of God and, from that conception, conclude that God exists. In the Arabic philosophical tradition, the Proof of the Truthful by Avicenna (Ibn Sīnā, d. 428/1037) is regarded by some contemporary philosophers as an ontological argument for the existence of God, while others do not consider his argument as purely ontological, because of his premise that something exists, which is known empirically.1 Moreover, the conception of divinity in his conclusion was rejected by orthodox Islam as both rationally incoherent and scripturally untenable.2 Nevertheless, the tradition of Sunni scholastic theology (kalam) benefited from Avicennian metaphysics and appropriated from it certain conceptual tools and methods, such as the modal categories in logic and the related term the necessarily existent.

This essay offers an attempt at an ontological argument that employs many conceptual tools of the kalam tradition and thus reflects contributions of Avicenna and of scholars such as Abū al-Ĥasan al-Ash¢arī (d. 324/936), Abū Manśūr al-Māturīdī (d. 333/944), Abū Ĥāmid al-Ghazālī (d. 505/1111), Fakhr al-Dīn al-Rāzī (d. 606/1210), and others. The classical kalam argument begins with the empirical premise that the world exists, and it is therefore a cosmological argument. While much of the argument presented here resembles the kalam cosmological argument (KCA), it has no empirical premises and thus can be termed a kalam ontological argument. The KCA is a sound demonstrative proof, meaning its premises are known with certainty, its syllogistic form is valid, and it therefore yields a conclusion known with certainty. As such, the argument presented here is not offered due to any deficiency in the cosmological version. But a sound ontological argument would show that even without human experience of the world, pure reason itself necessarily arrives at the existence of God. And, unlike most ontological arguments in Western philosophy, which begin with some specific conception of God, the point of departure for this argument is the concept of reality, and its conclusion is that reality cannot exclude the divine. Hence, God is real. In that way it resembles Avicenna’s point of departure with existence itself and, critically, avoids the common objection against the arguments of Anselm and Descartes that they are begging the question (or more crudely, that they are trying to “define God into existence”).3 Yet, unlike Avicenna’s argument, this argument concludes with the same conception of the divine as deduced in the KCA and presented in classical Sunni doctrine. Moreover, while this argument employs no premises taken from scripture, it can be seen as a conceptual unpacking of the Arabic divine name al-Ĥaqq (the Real) revealed in the holy Qur’an.4

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Reality connotes extra-mental existence (what actually exists), and conceptually, existence can be either metaphysically necessary or possible. Possible existence refers to the existence of something contingent and conditional—that is, the essence of which does not entail its extra-mental existence. In contrast, necessary existence is by definition absolute and not dependent on anything; something necessarily existent must exist, by its very essence, by definition. The remainder of this argument will demonstrate the coherence of the concept of “necessary existence.” The argument does not assume its coherence by begging the question; rather, it demonstrates by reductio ad absurdum that there is no logical alternative to affirming a necessarily existent entity, as otherwise some metaphysical impossibility is affirmed.

For any possible existent, a number of metaphysical possibilities can be attributed to it as its properties or conditions. For example, humans, cows, and trees are metaphysical possibilities, and each of these can be either living or not living, in a particular place or not, of a particular size or not, etc. If one reflects on any possible property of a metaphysical possibility, it can be either present or absent, yet both its presence and absence cannot simultaneously be true. Otherwise, a contradiction is affirmed, which is conceptually and metaphysically impossible. Thus, the only way a metaphysical possibility can actually have any properties or qualities—which it must have if it is to exist—is for it to exist within a temporal nexus, for only time allows for the presence and the absence of any property, without contradiction. That is, a possible existent can be of a certain size and then not be of that size, it can be in a certain place and then not be in that place, or it can be living and then dead or vice versa. Thus, any possible existent must by definition be changeable5 and must by definition be temporal, bound as it is to the temporal categories of past, present, and future. Inherent to the very essence of any possible existent is time, which limits and conditions its existence.

In light of its temporality, a possible existent must necessarily have a beginning, for the notion of an infinite past entails an analytic contradiction. Conceptually, the infinite6 is that which has no end, yet the past of anything has been completed and ends with the present moment. So, an infinite past would entail the ending of the never-ending or the completion of what cannot be completed. Hence, any possible existent necessarily had a beginning: it was originally nonexistent and only entered into existence.

Now, anything that has a beginning necessarily had a cause of its existence. This cause cannot be the effect itself, because the notion of “self-causation” is inconceivable: the act of causing presupposes the existence of a cause. This causal principle itself is not discovered a posteriori but rather known a priori, for it is a necessary first principle of reasoning itself. Denial of the causal principle is incoherent, because denial of anything requires causality in its very aim of convincing the interlocutor in a dialectic: premises lead to a conclusion only through causality, and sound conclusions convince other people only through causality. Arguments against the causal principle are effectively rendered mute, since causality has been either removed altogether or reduced from a necessary first principle to an indefinite probability. Lastly, appealing to “brute facticity” (to say that a possible world is simply a brute fact or “just there”) is not an application of reason but rather an attempt to escape its unequivocal conclusions.7

The cause of a possible existent can conceivably be either metaphysically necessary or metaphysically possible. If the cause itself is merely possible, then it too needs a cause, which would be either necessary or possible. But an infinite regress of possible causes is metaphysically impossible, because, as discussed above, the notion of completing or achieving an infinity is self-contradictory and therefore rationally inadmissible. Hence, the causal series must originate from a cause that is metaphysically necessary—that is, the essence of which entails its existence. The existence of this ultimate cause must therefore be absolute, without any conditions or limits. Its essence must be pure being, independent of time, space, or any mere metaphysical possibility.

To say that something besides God is real is in essence to say that it is an act of God: were it not for the divine act of causing its existence, a metaphysical possibility could never exist.

Consequently, based on the rational impossibility of infinite past time or an infinite regress of possible causes, and based also on the rational necessity of the principle of causality, the very concept of reality ends at an entity whose existence is metaphysically necessary and absolute, independent and self-sufficient, and transcendent above any temporal nexus of past, present, or future. This entity cannot be confined to moments of time or any other limits, cannot have a beginning or conceivable end, and is therefore eternal. Hence, it cannot change or actually resemble anything possible and temporal. Such a conception is essential to what the term the divine signifies in classical Sunni theology. 8Reality, therefore, by definition cannot exclude the divine being.



Now, if no possible existent actually existed, then it would seem that the above conception of the divine is the extent that a priori reasoning could conclude with. (One could, perhaps, assert that a priori reasoning is itself a temporal process and is metaphysically merely possible, and then proceed with what follows below. But this argument will avoid self-referential premises, as they might render the argument “not fully ontological.”) But if a metaphysical possibility existed,9 additional necessary divine attributes could be deduced a priori from the existence of that possibility. Anything possible could actually exist only if the necessarily existent divine entity possessed the attributes of (1) power, to cause the existence of the possibility; (2) will, to select its existence and any of its conceivable accidents (e.g., qualities, traits); (3) knowledge, because selection is not conceivable without knowledge; and (4) life, given that only a living entity can possess knowledge and choice. These four attributes must be eternal qualities of the divine entity and must be distinct attributes that are neither identical to the entity nor separable from it, given that the eternal is by definition unchangeable, for no temporality obtains with its being. Only something bound by time and existing sequentially within moments of time can change.

Moreover, the divine attributes of knowledge, will, and power cannot conceivably be limited in any way, for only something temporal and possible can be limited. Thus, anything that can conceivably be known must be known to Him, and anything metaphysically possible must be within the scope of His divine will and power. His knowledge is therefore omniscience, and His will and power omnipotent. As such, His entity must necessarily be one and unique, without any duality or partnership in His divinity. Were there a second eternal deity (or second person in divinity), either or both deities would necessarily be limited in will and in power, which contradicts the omnipotence entailed by eternality and thus the very eternality and necessary existence of divinity. Because plurality entails limits of each member, and because only what is temporal can be limited, there can be no category of “divine entities” with members or persons. The absolute plenitude of eternality contradicts restriction or limitation, and it therefore contradicts sharing or partnership. The eternal can only be one.