In responding to this question, first the media of understanding must be introduced. The media of understanding are the physical senses, the intellect, and the heart. The external senses merely deal with the appearances and the accidents of things without being able to delve any deeper, and despite the variety and abundance of knowledge they provide to the human being, they are limited by time and space.

The intellect is a special faculty, the major role of which is the comprehension of universal concepts and in this sense possesses many aspects - among them reasoning. But the media of understanding are not restricted to these two. The human being can reach great degrees of knowledge through the medium of the heart. By this way, the human being can spiritually witness [the reality of] what others understand [only theoretically] through reasoning. The gnostics’ endeavour is to comprehend Allah (awj) in this way.[1]

From another perspective, knowledge can be divided into two general categories: conceptual knowledge and presential or immediate knowledge. Conceptual knowledge is obtained through mental concepts and the implementation of rational and philosophic reasoning. Presential knowledge is the knowledge arrived at without the mediation of concepts and mental pictures; that is, the reality of the known object is present within the knower. Presential knowledge is a type of gnostic and intuitive knowledge, in which the external reality [and not the mental concept] of an object is witnessed.

Of course, in the obtainment of rational conceptual knowledge, sensory and empirical premises can be employed. For instance, by reflecting on the signs of Allah (awj) and the existing order in the cosmos, one can achieve an understanding of Allah (awj) that is rendered by a simple reasoning. But in cases where one desires to achieve a greater understanding, purely rational premises are required.

In any case, it must be borne in mind that firstly, Allah (awj) cannot be proven nor refuted by exclusive recourse to laboratory experiments or scientific, empirical principles for the grasp of sensory experimentation is far shorter than to be able to pierce into the supernatural. Therefore, sensory knowledge alone cannot solve the problem, it must be employed in the premises of rational reasoning [if it is to be useful]. Secondly, despite the fact that in Islamic texts, studying the extroversive (afaqi)[2] signs of Allah (awj) has been encouraged,[3] which is in a sense considered a rational method since it involves reasoning, it must not be overlooked that studying the creatures, the signs of Divine creativity and wisdom, only reveals that there is an omnipotent and omniscient being governing the world; but other than that, this method fails to render the attributes of that being; for instance, whether it is self-sufficient.

As for intuitive and immediate comprehension, it can be conceived in three ways: a cause’s immediate knowledge of its effect, an immaterial existent’s immediate knowledge of its own essence, [and finally] an effect’s immediate knowledge of its cause. The creatures’ awareness of Allah (awj) is of the third type. And the human being’s weakness in comprehending Allah (awj) is in proportion to his [existential] weakness. Thus, although that Sacred Essence is proximate to everything, but their proximity to Him depends on their existential degree and limit.

Muhaqqiq Tusi provides a good analogy regarding the degrees of knowledge of Allah (awj). He says one’s knowledge of Allah (awj) resembles one’s knowledge of fire, the most limited form of which is being told the qualities of fire by somebody else who has seen it. A more advanced awareness of fire is when one observes its smoke. The third degree is feeling the heat and witnessing the light it radiates. The final degree of knowledge of fire is being inflamed and burned to ashes.

A point necessary to mention at this stage is that in speaking of knowledge of Allah (awj), we might either be referring to proving His existence or to contemplating His attributes. In both cases we can have recourse to the intellect to employ conceptual knowledge in order to understand intellectually, or we can go through the path of the heart, to embark on immediate intuitive knowledge in order to behold. The former is termed burhan, the latter, ‘irfan. Without question, the method prevalent in philosophic reasoning is not as valuable as gnostic revelations.

In any case, regardless of whether we traverse the path of the intellect or the heart, there are three ways for acquiring knowledge of Allah (awj). In other words, the intellectual or gnostic journey of the philosopher or the spiritual wayfarer [respectively] could fall under one of three categories:

1. The traveller (salik), the path (maslak), and the goal (maslk ‘ilayh) are distinct; such as if one reaches the conclusion [that Allah (awj) exists] by observing and contemplating the order and harmony of the universe, by realizing that all things are needy and so there must be something needless they depend on, hence the Originator. Some Qur`anic verses encourage people to take up this method.[4]

2. The traveller and the path are one and the same; such as if one contemplates the world within himself, addressing questions such as, “Who am I?”; “Where am I from?”; “Why aren’t my inclinations, my allegiances under my control?”; “Why can I not tame my wild mind so as to control what memories it recalls?”  

Imam ‘Ali b. Abi Talib (ع) alludes to this method in the following words: “I came to know Allah by observing the strong wills that trembled, the difficult entanglements that were disentangled, and the decisions that were crushed.”[5] In another instance he says, “Whoever comprehends himself has indeed comprehended his Lord.”[6]

3. The path and the goal are one and the same. That is, the traveller—the philosopher or the spiritual wayfarer—by contemplating the destination discovers the object of his desire (maqsud). This is the most profound way of understanding, for it transcends the levels of extroversive and introversive journeys, thereby realizing, through contemplating the Absolute Witness, that Allah (awj) is the Absolute Witness.

The Qur`an states:

“Is it not sufficient that your Lord is witness to all things?”[7]

First, He is witnessed and comprehended, and then [in His light] all other things, for He is the Light of the Heavens and the Earth. The Essence of Unicity [i.e. Allah (awj)] is the clearest witness to and proof of Himself and as such, renders unnecessary any intermediary for comprehension of Him.[8]

So it is that in addressing His messenger He says,

“You were certainly oblivious of this. We have removed your veil from you, and so your sight is acute today.”[9]

The veil is removed from the individual, not from the reality or from Allah (awj).

In the Supplication of ‘Arafah, Imam Husayn b. ‘Ali (ع) deals with this third method. He says, “O Allah!  Do others possess a light that You lack so that they must shed light upon You? When have You been absent so as to be needy of proof? When have You ever been distant so that Your effects and creatures should move us close to You?”[10] 

The same theme resonates in the following couplet: “You have never distanced Yourself so that I should seek Your presence. You have never been hidden so that I should make You manifest.”

And again in the words of Imam Husayn b. ‘Ali (ع), “Blind be the eye that does not behold You … It is You whom I beseech in seeking union with You, and it is Your own existence that I seek as proof for Your existence.” In this phrase, it is expressed that for the spiritual wayfarer, Allah (awj) is more manifest than the sky, the earth, the leaves of trees, etc.

Imam Ja’far b. Muhammad as-Sadiq (ع) alludes to this point in the following words: “When someone is present and manifest, we first know him through his self, then we get to know his attributes. But in the case of something absent, knowledge of its attributes precedes knowledge of its essence … Just as in the case of Yusuf’s brother, they studied Yusuf himself and recognized it was him. They asked him, ‘Are you really Yusuf?’ They did not formulate their question the other way around[11]; meaning, they reflected on the qualities of the person whom they were confronted with and realized that he was Yusuf. They did not ask others to identify Yusuf for them.”[12]

Based on the aforementioned explanations, it has been concluded that contingent existents are realities whose existence is nothing but their relation to the Necessary Existent. Otherwise, they would be needless in their essences which would in turn mean that they would be necessary by their essences, which is obviously false.

Thus, they are in their entire existence dependent on the Necessary Essence and it is impossible to view the relation [i.e. the creature, for as previously mentioned the contingent existent is nothing but that relation] without the object to which it is related (marbut ‘ilayh). That is, comprehending the effect independent of its cause is impossible. Thus, the comprehension of every thing, even purely material existents, is concomitant with comprehending the Necessary Existent.

Although knowledge is of two types: simple knowledge and compound knowledge, even as ignorance is of both types. Simple knowledge is one’s knowledge of an issue without being aware of the existence of that knowledge. Compound knowledge is when one’s knowledge is realized; that is, when one knows that he knows. We are of the opinion that a knowledge of Allah (awj) exists in all human beings; it could be conceptual or presential and the object of that knowledge could be anything. That is, when one comprehends something, whether through conceptual knowledge or presential knowledge, he has comprehended Allah (awj) along with it.[13] The Qur`an states, “He is known to every one ignorant of Him.”[14] Even the person in doubt comprehends Allah (awj) prior to comprehending his doubt for Allah (awj) is the cause of his doubt and so the doubt is nothing but a relation to Allah (awj). So yes it is true; some are unaware of their knowledge of Allah (awj) and as such are oblivious to this necessary comprehension.

Therefore, when Imam ‘Ali b. Abi Talib (ع) said, “I do not see anything but that I see Allah prior to it” or “I do not worship a Lord I do not see”[15] he was aware of his knowledge. He had grasped the truth of the verse,

“…so whichever way you turn, there is the face of Allah.”[16] The face cannot be beheld without beholding the possessor of the face. He was a gnostic who through voluntary extinguishment witnessed, in this world that other-than-Him is hidden and it is He, the Creator, Who is manifest, and it was because of this that he said, “If the veils were to be lifted, my certainty would not increase.”[17]

Whatever serves as an obstacle tosight or understanding is referred to as a veil. A veil is either of darkness or of light. Regarding the veil of darkness which is the veil of materiality, there are three elements: the subject from whom the matter in question is hidden, the veil, and the veiled [i.e. the object that is hidden]. But regarding the veil of light there are only two elements: the veiled and the subject from whom the matter in question is hidden. Obscurity in the latter case is the result of the intensity of the brightness of the veiled, or more accurately as the result of the weakness of perception on the part of the subject. As an analogy, one is incapable of seeing the sun in some cases, because of an obstacle, such as a wall or dust, or at other times because of the intense brightness of the sun, which is actually the result of the weakness of one’s vision.

A poet has said: “The veil that conceals Your face is Your face, at all times; You are hidden from the world as You are so manifest.”

Between Allah (awj) and His creatures, there are no obstacles except His creatures.[18] If the human being succeeds in removing the veils of darkness, of egocentrism, and of desire, only then can he turn to removing the veils of light.

It is for this that in the Sha’baniyyah Supplication, one pleads to Allah (awj) for the rending of the veils of light.[19] Other than the Prophet (ص) and the Ahlul Bayt (ع) no one is capable of rending all the veils of light. Of course, the core of the Divine Essence and Attributes is impregnable even to them.[20] Therefore, they are themselves veils of light for viewing the Divine Essence and since a contingent being cannot escape being limited, they also gaze at Allah (awj) from the outlook of their own [limited] existences;“‘Unqa[21] is not the game to be ensnared, so remove your net.”

Hence, the knowledge of every knowing being is limited to the framework of its existence and to the extent that it lacerates the veils. Imam ‘Ali b. Abi Talib (ع) in this regard says, “The intellects will never have the capacity to reach to the core and circle of His Attributes. Nevertheless, there is no veil to obstruct anyone in comprehending the necessary level [of knowledge of Allah].”[22] That is, on the one hand, all the existents of the world of contingency are Divine signs and as such serve as mirrors[23]reflecting a true image [of the Divine] but at the same time, they are not separable from the Divine. Basically, they have no other role but to reflect the beauty of the Divine, although “children” [i.e. intellectually and spiritually immature persons] might perceive them as separate entities.

On the other hand, “[those standing at] the apices of [intellectual] resolve cannot comprehend Him, and [those who have] dived in [the depths of] acuity cannot reach Him.”[24] His Essence neither yields to the intellection of the sage[25], neither to the spiritual experience of the gnostic[26], thus they both admit their incapability. This incapability arises because comparing what a contingent being can comprehend of Allah (awj) with what it cannot comprehend is to compare finitude with infinity.

At the end, the point that must be mentioned is that in the Islamic corpus of narrations there is mention of an innate knowledge of Allah (awj). Innate knowledge is of the intuitive, presential knowledge, which was explicated previously.

There are two types of innate qualities in the human being: innate understandings (which every human being possesses prior to any education) and innate inclinations (which are part and parcel of the nature of every human being). The former are referred to as “innate knowledge of Allah (awj)” and the latter as “innate worship of Allah.” But, as mentioned previously, they are not present at a conscious level of the human mind so as to render a rational endeavour [to understand Allah (awj)] unnecessary. Nevertheless, since knowledge of Allah (awj) is innate, the arguments presented in favour of Allah (awj) serve actually as reminders and not real proofs. In the process of proving something, one realizes that he has acquired a knowledge which he formerly lacked. But being reminded is to become aware that one has had something all along, albeit unknowingly. Thus it is that in Qur`anic verses and in narrations, what is always mentioned is the removal of the veils of obliviousness. And what rids one of a state of obliviousness is a reminder not a proof.