Epistemology is the academic discipline that addresses the question, “How do I know what I know?” In other words, it studies how knowledge is established, what makes a belief justified, what constitutes proof, and so on. Often surface-level polemics are in fact representative of deeper epistemological issues. This is certainly the case with debates over the existence of God. Before answering the demand, “Prove to me that God exists,” one must first examine what actually constitutes proof, what needs to be proven, and whether the one requesting proof has a coherent notion of proof to begin with. The present essay extracts and analyzes the common epistemological thread that runs through three seemingly disparate discussions: the problems of philosophical skepticism in the Hellenic and Hellenistic periods in Ancient Greece,[2] the critique of safsaṭah (sophistry) as it relates to philosophical proofs for the existence of God in the writings of the Muslim theologian Ibn Taymīyyah (d. 728 AH/1328 CE), and the core epistemic area of contention in contemporary debates between theists and atheists.
Living in what has been described as an era of doubt or the ‘Age of Atheists,’[3] people are far more skeptical towards religion and view faith derisively as ‘belief without evidence,’ or beliefs lacking justification. Faith’s ultimate justification, however, is encountered through the meaningfulness of its own message and not through the pursuit of philosophical argumentation. The essential idea at the core of this essay is the following: philosophical proof is not required in order to believe in God, nor to justify one’s belief in God.[4] That doesn’t mean that people are not to be persuaded by some sort of explanation or justification, only that the justification offered must primarily focus on Islam’s theocentric message regarding the purpose and meaning of life rather than on syllogistic cosmological, teleological, or ontological arguments. People can entertain doubts about all sorts of things; just as a person does not need philosophical proof to rescue them from the idea that ‘the physical world does not exist’ or that ‘moral values do not exist,’ they do not need philosophical proof to escape atheism. There is a fallacy, then, in thinking that we must necessarily doubt and demand proof for something before it can be established as veritable truth—a fallacy one can term the ‘Pyrrhonian fallacy’ after the radical skepticism of the Ancient Greek philosopher Pyrrho of Elis (d. 270 BCE), who is discussed in detail later in the essay.
The use of philosophical proofs to substantiate doctrines of faith was common in the discipline of kalām,[5] becoming a central feature of the discourse.[6] However, the eminent Ashʿarī theologian Abū Ḥāmid al-Ghazālī (d. 505 AH) explained that it was not the means of securing certitude for many people since this was not its original aim. Rather, according to him, kalām was intended as a discourse for the rational defense of doctrine that demonstrated the logical contradictions of heterodox groups.[7] In his spiritual autobiography, al-Munqidh min al-ḍalāl, al-Ghazālī describes how he overcame his own struggle with Pyrrhonian doubt through spiritual experience and enlightenment rather than philosophical argumentation.[8] 
The most voluminous and vociferous intellectual opposition to the use of philosophical argumentation to establish religious doctrine was to come in the writings of Shaykh al-Islām Ibn Taymīyyah. As numerous academics have noted, Ibn Taymīyyah’s writings demonstrate that he is not an unthinking anti-rational literalist, but rather a deeply analytical and systematic rationalist, intimately familiar with the vast philosophical tradition drawn upon by his opponents.[9] He advocated for a logically coherent epistemology that gave scripture its due reverence rather than what he perceived to be rendering it subservient to fallible man-made ideologies.[10] Perhaps Ibn Taymīyyah’s most salient contribution has been to refocus debates over the interpretation of scripture back to their epistemological roots, namely, the presumption that theological doctrines must be substantiated by philosophical argumentation in order to be regarded as true.
According to the Qur’anic epistemology elaborated by Ibn Taymīyyah and his student Ibn Qayyim al-Jawzīyah (d. 751 AH), a person’s faith in God is fully justified and meaningfully grounded without need for logical deductive argumentation.[11] It is instead justified because it is the only meaningful outlook that emerges naturally from a person’s fiṭrah (innate disposition)—just like belief in the existence of good and evil, causality, numbers, truth, existence itself, and so on.[12] To deny a core pillar of one's fiṭrah leaves a person without a coherent system of interpreting existence in a meaningful way and, if taken to its logical conclusion, one’s beliefs dissolve into endless doubt as in safsaṭah—a term used in the Islamic tradition to designate radical (Pyrrhonian) skepticism. These terms will be further unpacked and explored in the course of this essay.
Three works of Ibn Taymīyyah are of particular significance in noting his views on philosophical justification: the gargantuan ten-volume work entitled Darʾ taʿāruḍ al-ʿaql wa al-naql (Repudiating the Conflict between Reason and Revelation), his work on Aristotelian epistemology entitled al-Radd ʿalá al-manṭiqīyīn (Refutation of the [Greek] Logicians), and his work entitled Naqḍ al-manṭiq (Nullifying [Greek] Logic).[13] Over the course of a sustained epistemological critique, Ibn Taymīyyah traces his interlocutors’ methodology of argumentation back to a philosophy prone to radical skepticism and doubt, in order to advance the case for scripturalist (atharī) theology.[14] He argues that those who took up the path of philosophical argumentation to attain certainty were often the ones most afflicted by uncertainty, confusion, and doubts, and in many cases, they ended up acknowledging a stalemate on arguments.[15] 

Dubiously demanding proof

Skepticism beyond solipsism

The spectrum of skepticism

Proof and the Pyrrhonian precipice

The meaning of safsaṭah

Atheism and safsaṭah

The epistemology of primordiality

Is there any epistemic merit to philosophical proofs?

Ibn Taymīyyah, the fiṭrah, and Agrippa’s trilemma[142]

Pyrrhonian skepticism and the epistemology of disagreement

UFOs, leprechauns, unicorns, the Tooth Fairy, and Flying Spaghetti Monsters: When is skepticism reasonable?

The meaning of meaningfulness