Ibn Rushd, shortly after writing his Decisive Treatise, wrote a treatise on the doctrine of God known as Al-Kashf 'an Manahij al-Adilla fi ‘Aqaid al-Milla (the Exposition of the Methods of Proof Concerning the Beliefs of the Community). His goal was to examine the religious doctrines that are held by the public and determine if any of the many doctrines expounded by the different sects were the intention of the "lawgiver".

In particular he identifies four key sects as the targets of his polemic, the Asharites, Mutazilites, the Sufis and the “literalists,” claiming that they all have distorted the scriptures and developed innovative doctrines not compatible with Islam. Ibn Rushd's polemic, then, becomes a clear expression of his doctrine on God. He begins with examining the arguments for the existence of God given by the different sects, dismissing each one as erroneous and harmful to the public. Ibn Rushd contends that there are only two arguments worthy of adherence, both of which are found in the "Precious Book;" for example, surahs 25:61, 78:6-16 and 80:24-33. The first is the argument of “providence,” in which one can observe that everything in the universe serves the purpose of humanity. Ibn Rushd speaks of the sun, the moon, the earth and the weather as examples of how the universe is conditioned for humans. If the universe is, then, so finely-tuned, then it bespeaks of a fine tuner - God. The second is the argument of “invention,” stemming from the observation that everything in the world appears to have been invented. Plants and animals have a construction that appears to have been designed; as such a designer must have been involved, and that is God.

From establishing the existence of God, Ibn Rushd turns to explaining the nature and attributes of God. Beginning with the doctrine of divine unity, Ibn Rushd challenges the Asharite argument that there cannot, by definition, be two gods for any disagreement between them would entail that one or both cannot be God. This, of course, means that, in the case of two gods, at least one's will would be thwarted in some fashion at some time by the other; and such an event would mean that they are not omnipotent, which is a essential trait of deity. Ibn Rushd’s critique turns the apologetic on its head, contending that if there were two gods, there is an equal possibility of both gods working together, which would mean that both of their wills were fulfilled. Furthermore, Ibn Rushd adds, even disagreement would not thwart divine will, for alternatives could occur giving each god its desire. Such arguments lead to absurdity and are not fit for the masses. The simple fact is that reason affirms divine unity, which, by definition, is a confession of God’s existence and the denial of any other deity.

Ibn Rushd maintains, as did most of his theologian contemporaries that there are seven divine attributes, analogous to the human attributes. These attributes are: knowledge, life, power, will, hearing, vision and speech. For the philosopher, the attribute of knowledge occupied much space in his writing on the attributes of God. He contends, especially in his Epistle Dedicatory and his Decisive Treatise that divine knowledge is analogous to human knowledge only in name, human knowledge is the product of effect and divine knowledge is a product of cause. God, being the cause of the universe, has knowledge based on being its cause; while humans have knowledge based on the effects of such causes.

The implication of this distinction is important, since Ibn Rushd believes that philosophers who deny God's knowledge of particulars are in error. God knows particulars because he is the cause of such things. But this raises an important question: does God’s knowledge change with knowledge of particulars? That is, when events or existents move from non-existence to existence, does God’s knowledge change with this motion? Change in divine knowledge would imply divine change, and for medieval thinkers it was absurd to think that God was not immutable.

Ghazzali answered this dilemma by saying that God's knowledge does not change, only his relationship with the object. Just like a person sitting with a glass of water on their left side does not fundamentally change when that same glass is moved to their right side. Ibn Rushd felt that Ghazzali’s answer did not solve the dilemma, stating that a change in relationship is still change. For Ibn Rushd, then, the solution came in his contention that divine knowledge is rooted in God being the eternal prime mover; meaning that God eternally knows every action that will be caused by him. God, therefore, does not know that event when it occurs, as humans would, because he has always known it.

As for the other traits, Ibn Rushd next turns to the attribute of life, simply stating that life necessarily flows from the attribute of knowledge, as evidenced in the world around us. Divine will and power are defined as essential characteristics of God, characteristics that define God as God. This is because the existence of any created being implies the existence of an agent that willed its existence and had the power to do so. (The implication of this, Ibn Rushd notes, is that the Asharite concept that God had eternally willed the existence of the world, but created it at some particular point in time, is illogical.)

In regards to divine speech, Ibn Rushd is aware of the great theological debate in Islam about whether the Qur'an, the embodiment of God’s speech, is temporally created or eternal. Ibn Rushd contends that the attribute of divine speech is affirmed because it necessarily flows from the attributes of knowledge and power, and speech is nothing more than these. Divine speech, Ibn Rushd notes, is expressed through intermediaries, whether the work of the angels or the revelations given to the prophets. As such, "the Qur’an…is eternal but the words denoting it are created by God Almighty, not by men." The Qur’an, therefore, differs from words found elsewhere, in that the words of the Qur’an are directly created by God, while human words are our own work given by God’s permission.

Ibn Rushd concludes by discussing divine hearing and vision, and notes that scripture relates these attributes to God in the sense that he perceives things in existing things that are not apprehended by the intellect. An artisan would know everything in an artifact he had created, and two means of this knowledge would be sight and sound. God, being God, would apprehend all things in creation through all modes of apprehension, and as such would have vision and hearing.