“Epistemological wall” as selection criterion: An Alternative Abrahamic trio to Averroes, Maimonides, and Aquinas
Conf: Trespassing Walls: Jews, Christians, and Muslims around their Texts and Traditions
Research attempting to bring down the walls between the three Abrahamic faiths rightly draw on their shared historical and philosophical developments within Aristotelianism and Classical Theism. These attempts frequently present a paragon thinker from each faith, or at least the most renowned, namely: Averroes (d. 1198), Moses Maimonides (d. 1204), and Thomas Aquinas (d. 1274). Since Averroes may have influenced Maimonides and both Averroes and Maimonides clearly influenced Aquinas, this trio allows for the tracing of philosophical ideas across time and faith. However, other than historical precedent, the selection criterion used to arrive at these three thinkers is not readily apparent, or at worst, reflects an Orientalist mentality beginning with Aquinas and moving to the non-Christian thinkers he relied on. Since Aquinas, Maimonides, and Averroes hold differing methods to certain knowledge which result in very different philosophical schemas, I argue for an alternative selection criterion based on a key epistemological limit to group likeminded thinkers across the three Abrahamic traditions.
The selection criterion I propose is what I term the “epistemological wall” or the end of reason. Thinkers who allow divine testimony to go beyond reason’s limits fall into one camp I am calling “limited rationalism” while the alternative camp of “strong rationalism” refers to thinkers who perceive reason as the sole path to knowledge either by rationally demystifying divine prophecy or allowing no room for supernatural guidance. In what follows, I will elaborate on the distinction between the “strong” vs. “limited rationalism” epistemological methodologies. Afterwards, I will show that the traditional trio of Averroes, Maimonides, and Aquinas draws from both methodologies while overlooking the difference. Then I will propose alternative sets of thinkers based on the selection criterion of the “epistemological wall”, focusing mainly on limited rationalists who allow divine testimony to trespass this epistemic wall to obtain certain knowledge, namely Saadya Gaon, al-Ghazali, and Thomas Aquinas.
Strong vs. Limited Rationalism
In distinguishing the difference between what I am referring to as strong and limited rationalism, the “epistemic wall” should become apparent. “Strong rationalism” refers to the idea that Aristotelian science (“reason”), as outlined in Posterior Analytics 1.2, is the sole path to certain knowledge. While recent Aristotle scholars have suggested that Aristotle likely had in mind a weaker notion such as “understanding”, here I refer to the Aristotelian tradition following al-Kindi’s goal to develop a philosophy that could rival the certainty of mathematics, a hard episteme in which knowledge is certain. The method to obtain certainty is thus based on Aristotle’s metaphysics, in which a validly formed demonstrative syllogism built on true premises necessarily yield true conclusions. When demonstrative knowledge contradicts revealed religious knowledge, the apparent sense of the religious law must be reinterpreted to fit the demonstrative conclusion or accord with double-truth (i.e., holding to two contradictory truths, one taught by philosophy and one commanded by faith). Since Aristotelian demonstrative knowledge is the strongest and most certain form of knowledge, any claim unproveable by reason cannot obtain certainty, and if certainty equals knowledge, then such claims are effectively unknowable. This limit or end of reason is the “epistemic wall.”
“Limited rationalism” refers to epistemological methods that accept the strength of Aristotelian scienc but trespass the “epistemic wall” by asserting that knowledge beyond demonstration is possible by another means, typically labeled “faith”. The end of reason is not the end of knowledge since demonstration is not the only way to certain knowledge. Such extra-demonstrable knowledge typically comes through God’s testimony (assertions from an omniscient and trustworthy being) in the form of revelation or religious law making it “certain” knowledge which compliments natural reason. While some knowledge is only obtainable via one method or the other, faith and reason are not mutually exclusive and can reach the same conclusions. Hence, allowing the methods to complement one another provides the most expansive epistemological picture. Strong rationalists often took issue with such “faith”-based approaches by accusing speculative theologians, such as the Mutakallimun, of incorporating revelatory premises unproven by natural causes or reason into their demonstrations or using reason post hoc to explain presupposed religious opinions. The fear is the methods of limited rationalism render reason subservient to revelation, not its complement.
Alternative Trios based on the Epistemological Wall
Alternative Strong Rationalist Trio: Maimonides, Averroes, and Siger Brabant
Using the “epistemic wall” as the selection criterion, we can see that Maimonides and Averroes fit comfortably in strong rationalism (and as we shall see, Aquinas does not). A telling example is their explanations of prophecy, the primary medieval understanding of how God communicated non-demonstrable certainty. In brief, for Maimonides prophecy is a rational process, an emanation of an intelligible form from God via the causality of the Agent Intellect. Prophets require the necessary rational faculties to receive the intense degree of the intellectual emanation and the necessary imaginative faculties to concretely represent what they received intellectually. Averroes likewise describes a true prophet not as revealing knowledge beyond the limits of reason but making knowledge and laws known that “are in accordance with the truth and which bring about acts that will determine the happiness of the totality of mankind.” As such, Religious Law must yield to philosophical demonstration when conflicts arise such that the apparent meaning must be reinterpreted in light of an “inner-meaning.” For strong rationalists, prophecy is merely another form of rational knowledge using the same epistemology as science and metaphysics.
So what Christian thinker could round out a trio of Abrahamic strong rationalists? I propose Siger Brabant (d. 1281) or his colleague Boetius of Dacia (d. 1284), professors of philosophy at the University of Paris. Both were contemporaries of Aquinas and they too were influenced by Maimonides and Averroes. These thinkers separated truths into two mutually exclusive modes: revealed truths known via a faculty of faith and rational truths known via Aristotelian logic. Boetius of Dacia even expressed the sentiment: “when someone puts aside rational arguments, he immediately ceases to be a philosopher; philosophy does not rest on revelations and miracles”. Consequently, both Siger Brabant and Boetius of Dacia were swept up the 1277 Paris Condemnations of “Latin Averroism” for holding to double-truth. This reveals how strong rationalist epistemologies often ran afoul of religious orthodoxy. A point confirmed by Kenneth Seeskin’s Stanford Encyclopedia of Philosophy entry regarding Maimonides which asks: “Is this the religion of the prophets or a philosophically sanitized religion concocted by a medieval thinker under the sway of Aristotle?” Seeskin’s answer: “Maimonides would reply that there is no difference.”
Alternative Limited Rationalist Trio: Thomas Aquinas, Saadya Gaon, and al-Ghazali
In his Summa Contra Gentiles, Aquinas famously outlines a “twofold mode of truth” (duplex veritatis modus), between knowledge obtainable by philosophical principles vs. divine testimony commonly differentiated as “preambles of faith” and “articles of faith” respectively (not to be confused with “double-truth”). In asserting that certain truths, such that God is triune, cannot be obtained by human reason but must be obtained by prophets acting as God’s instruments, Aquinas’s epistemology contains an “epistemic wall” placing him comfortably in limited rationalism. So what Jewish and Islamic thinker share a similar twofold approach to certainty that would round out a trio of Abrahamic limited rationalists? I propose Saadya Gaon and al-Ghazali.
Saadya was a Jewish Gaonim (the Gaonim were directors of Jewish academies and spiritual leaders of the Jewish communities from 589-1038CE). Colette Sirat in his History of Jewish philosophy in the middle ages describes Saadya as being convinced that “Torah and science spring from the same branch; they cannot contradict each other in any way”. Like Aquinas three centuries later, Saadya taught two acceptable approaches to knowledge: “laws of reason” (al-shari’a al-‘aqliyyât, or “rational/intellectual laws”) and the “laws of revelation” (al-shari’a al-sam‘iyyât, or “heard laws”), which together allowed for the dispelling of doubt. “Laws of reason” apply to what any rational agent can deduce by drawing on the first three “roots of knowledge”: sense perception (eye-witness), reason (intuition of the intellect), and inference (logical necessity). For Saadya, reason needs revelation because of the epistemic wall. Hence, the “laws of revelation” apply to the fourth “root of knowledge” gained from the Torah or oral teachings, both referred to as “the trustworthy report” (al-khibar al-sadiq), which is frequently translated as “Authentic Tradition.” The fourth root of knowledge is thus literally the “hearing” of “trustworthy reports” from God. Saayda thereby provides a perceptual account of prophecy that avoids anthropomorphizing God without falling into allegorism and psychologism but still maintains that the prophets really see and hear God via his Created Glory (kavod nibra) a “second air” which pervades the entire world and acts as a substrate or medium.
Al-Ghazali was a Nizamiyya in Baghdad (the most prestigious and challenging professorial position appointed by the vizier). He likewise held to two methods of obtaining certain knowledge. The “highest” form immune to error comes from a form of religious experience known as dhawq (literally a “tasting” of the divine comparable to mushahada--“actual seeing and handling”). Dhawq is thus the most desired state since it allows one to personally verify what one knows. This subjective personal verification, or “perfection” (istikmal) is the only real difference between knowledge received through dhawq and achieved through apodictic proofs. Demonstration (burhan) also obtains certain knowledge (ilm), but is subject to doubt due to error. Thus, his portrayal of an “epistemic wall” is probably best seen in his infamous Incoherence of the Philosophers. However, the rarity of dhawq makes philosophical methods invaluable. Finally, those not capable of burhan can rely on belief or faith, the “favorable acceptance” based on “hearsay and experience of others” (taqlīd). Interestingly, knowledge obtained by testimony is the least certain for al-Ghazali and even prophets can only be trusted when their claims are verified by theoretical knowledge even going so far as to claim in al-Qistas al-Mustaqim that the Qur’an can be trusted since it provides syllogisms which conform to reason. Thus, alGhazali claims that he “gives credence to the veracity of Muhammad and of Moses” not on account of their miraculous signs and wonders, but in the same way as one’s doubts about mathematics are dispelled by their teacher in arithmetic.
Like the trio with Maimonides and Averroes, these three thinkers were successive and represent medieval thought across the three Abrahamic faiths through three centuries (9th/10th Century – Saadya; 11/12th Century – al-Ghazali; 13th Century – Aquinas). Plus, their works were either available to or known to have been read and influenced one another (such as Aquinas’s use of al-Ghazali’s Maqasid in Latin translation). As shown above, these thinkers are also uniquely related in that they valued both reason and revelation, such that they desired to have sound rational explanations or arguments while maintaining orthodox formulations of the faith. As limited rationalist, they attempted to establish a middle ground between more heterodox philosophically or reason driven accounts embraced by thinkers such as Maimonides, Avicenna, and the “Latin Averroists” on one side, and more hardline faith-based approaches embraced by groups such as the Karaites, the Kalaamists, and the Augustinians on the other side. This is most clearly seen in their historical understanding of scriptural revelation as truths told by God himself, or God revealing through a rational account of testimony.
I have argued for an epistemological selection criterion, the “epistemological wall”, to divide thinkers who employ either “strong” or “limited rationalist” methodologies. After defining these two categories, I proposed alternative Abrahamic trios: Averroes, and Maimonides should be joined by Siger Brabant or Boetius of Dacia, while Aquinas should be joined by Saadya Gaon and al-Ghazali. This selection criterion better reveals how thinkers handled issues of knowing other than scientific demonstration, typically by incorporating revelation or divine guidance through God’s testimony. The relevancy of this criterion can still be seen today as famously expressed by Bertrand Russel who dismissed Aquinas as a philosopher since he did not “follow wherever the argument may lead” since to admit divine testimony did not qualify as a philosophic inquiry, but a “special pleading” for conclusions given in advance. This selection criterion will hopefully not only more accurately present these thinkers, but direct meaningful epistemological investigations such as how limited rationalists can verify when an omniscient and trustworthy being (i.e. God) is speaking, or how strong rationalists can first learn the Aristotelian sciences without relying on the testimony of knowledgeable and trustworthy teachers.
 W. By demonstration I mean a syllogism productive of scientific knowledge, a syllogism, that is, the grasp of which is eo ipso such knowledge. Assuming then that my thesis as to the nature of scientific knowing is correct, the premisses of demonstrated knowledge must be true, primary, immediate. better known than and prior to the conclusion, which is further related to them as effect to cause. Unless these conditions are satisfied, the basic truths will not be ‘appropriate’ to the conclusion. Syllogism there may indeed be without these conditions, but such syllogism, not being productive of scientific knowledge, will not be demonstration. (Posterior Analytics 1.2, 71b18-24, in Mure 1941, p. 112.)
 Taylor, Rationalism. 229.
 Averroes Incoherence of the Incoherence 1930: 516; tr. 1954: 316. See Taylor. Forthcoming. “Averroes and the Philosophical Account of Prophecy”. 6.
 “In the face of conflict with the apparent meaning of the religious law, Averroes refused to assert the possibility of a double truth and instead insisted that the apparent meaning of religious law be recognized as incorrect and requiring interpretation of its inner meaning when in conflict with philosophical demonstration.” Taylor 232
 Boethius, and John F. Wippel. 1987. On the supreme good ; On the eternity of the world ; On dreams. Toronto, Ont. Canada: Pontifical Institute of Mediaeval Studies. 65.
 See Dales, Richard. 1984. “The Origin of the Doctrine of the Double Truth”.
 Seeskin, Kenneth, "Maimonides", The Stanford Encyclopedia of Philosophy (Spring 2017 Edition), Edward N. Zalta (ed.), URL = <https://plato.stanford.edu/archives/spr2017/entries/maimonides/>.
 SCG I. 3 “There is a twofold mode of truth in what we profess about God. Some truths about God exceed all the ability of the human reason. Such is the truth that God is triune. But there are some truths which the natural reason also is able to reach. Such are that God exists, that He is one, and the like. In fact, such truths about God have been proved demonstratively by the philosophers, guided by the light of the natural reason.”
 Sirat, Colette. 1996. A history of Jewish philosophy in the Middle ages. 23.
 Saadya makes this division in Treatise III on Commands & Prohibitions, even explicitly stating in chapter 3: “Now that I have expressed myself in this summary fashion about the two general divisions of the precepts of the Torah (al-shari’a), namely the rational (al-‘aqliyyât) and the revealed (al-sam‘iyyât), it behooves me to explain why there should have been need for divine messengers and prophets.” Saʻadyah, and Samuel Rosenblatt. 1976. The book of reliefs and opinions. 145.
فاذ قد قلت هذه الجماه فى قسمى الشرائع وهما العقليّه والسمعيّه فينبغى ان ابين ما الحاجه الى رسل وانبياء
And also: “Then I pondered the matter deeply and I found that there was considerable need for the dispatch of messengers to God's creatures, not merely in order that they might be informed by them about the revealed laws (al-shari’a al-sam‘iyyât), but also on account of the rational precepts (al-shari’a al-‘aqliyyât).”
ثمّ تأملت النظر فوجدت حاجه الخلق الى الرسل حاجه ماسّه لا من اجد الشرائعالسمعيّه فقط ليعرفوهم اياّها بد من اجد الشرائع العقليّه
 Rosenblatt consistently renders للخبرالصادق as “Authentic Tradition,” which is literally “the trustworthy report.” This is further strengthened by Saadya’s view that authentic revelation can come about only by means of prophecy. Saʻadyah, and Samuel Rosenblatt. 1976. The book of reliefs and opinions. New Haven, Conn: Yale Univ. Press. 63.
وامّا نحن جماعه الموحّدين فنصدّق بهذه الثلاث موادّ التى للعام ونضيف اليها مادّه رابعه استخرجناها بالثلاث فصارت لنا اصلا وهى صحّه الخبر الصادق فانّه مبنىّ على الم للحسّ وعلم العقل كما سنبين فى المقاله الثالثه من هذا الكتاب | فصارت لنا اصلا وهى صحّه الخبر الصادق و الكتاب المنزله يحقّق لنا هذه ال اصول | انها علوم صحيحه لنه يحصى الحواسّ فى باب نفيها عن الوثان فيجعلها يعنم اليها اذ يقول
 As a perfect example, al-Ghazali argues how it is logical that God sent the words of Qur’an upon mortal men: 1) Moses is a man; 2) Moses is one upon whom the Scripture was sent down; 3) Some man has had sent down upon him the Book [the Qur’an] Ibid., 300.
 Ghazzālī, and David Pearson Brewster. 1978. The just balance: al-qistás al-mustaqim. SH. Muhammad Ashraf: Kashmiri Bazar Lamore, Pakistan. 72-73
 The critique mirrors that of Bertrand Russell’s contemporary critique of Aquinas: “There is little of the true philosophic spirit in Aquinas. He does not, like the Platonic Socrates, set out to follow wherever the argument may lead. He is not engaged in an inquiry, the result of which it is impossible to know in advance. Before he begins to philosophize, he already knows the truth; it is declared in the Catholic faith. If he can find apparently rational arguments for some parts of the faith, so much the better: If he cannot, he need only fall back on revelation. The finding of arguments for a conclusion given in advance is not philosophy, but special pleading. I cannot, therefore, feel that he deserves to be put on a level with the best philosophers either of Greece or of modern times” Russell, Bertrand (1945). A History of Western Philosophy. New York: Simon and Schuster. 463.