The theme of Averroes’ Decisive Treatise is, as he puts it, “to investigate, from the perspective of Law-based reflection, whether reflection upon philosophy and the sciences of logic is permitted, prohibited, or commanded – and this as a recommendation or as an obligation – by the Law.”:”(Averroes, The Book of the Decisive Treatise Determining the Connection Between Law and Wisdom & Epistle Dedicatory, trans. with introduction and notes by Charles E. Butterworth [Provo, UT: Brigham Young University Press, 2001], pg. 1. Hereafter, Decisive Treatise.)”: This is a theme which all the great monotheistic religions have in common with respect to entertaining the claims of philosophy.
Averroes “marks the climactic point in the development of Arab-Islamic philosophy and the conclusion of four centuries of philosophical-theological warfare in Islam.”:”(Majid Fakhry, Averroes (Ibn Rushd): His Life, Works and Influence [Oxford: Oneworld Publications, 2001], pg. xv. Hereafter, “Fakhry.”)”: Born in 1126, his life overlapped with other pivotal thinkers such as Peter Abelard (1079-1142), Peter Lombard (1100-1160), and Moses Maimonides (1135-1204). Averroes, something of a polymath, commented on Aristotle and Plato, and was a philosopher, physician, and a legal scholar. To his highly-trained legal mind, “If there is a revealed religious truth, it is necessarily in complete accord with rational truth.”:”(Roger Arnaldez, Averroes: A Rationalist in Islam, trans. David Streight [Notre Dame, IN: University of Notre Dame Press, 2000], pg. 3. Hereafter, “Arnaldez.”)”:
The historical context of the Decisive Treatise is the new openness to philosophy brought by the Almohades dynasty, which began in 1146.:”(The following survey is drawn from Fakhry, pp. 12-16.)”: Prior to this, conflict between two factions, the Mu‘tazilites (rationalists) and the Ash‘arites (irrationalists), wracked the Arab world. The former started in the eighth century with dialectical argument about theology (kalam). It birthed the first Muslim philosopher, Al-Kindi, who believed Islam and Greek philosophy to be compatible; Averroes would follow him in this. The Ash‘arites were an offshoot of the Mu‘tazilites, and leaned towards strict interpretation of religious “fundamentals.” The greatest of the Ash‘arites was Al-Ghazali (1058-1111), who drastically restricted the areas of religion into which philosophy could pry.
Although Averroes devoted much ink (The Incoherence of the Incoherence) to refuting Al-Ghazali, one of his best works is the Decisive Treatise, which has been described as dealing with the relationship of faith and reason “in a manner thoroughly comparable to Aquinas’ procedure in the opening parts of the Summa Theologica (Prima Pars) and his other works.”:”(Fakhry, pg. 139.)”: It is to the Decisive Treatise that we now turn.
Development of Themes in the Text
It has been argued that Averroes’ goal in the Decisive Treatise is not to explore the relationship between faith and reason abstractly, but to determine whether there is a “parentage,” or concrete connection, between “the way of life according to the wisdom that philosophy has as its goal, and the way of life according to Religious Law, which is revealed.”:”(Arnaldez, pg. 79.)”: Averroes begins the work with a logical argument that the Qur’an itself (Law) requires rational demonstration of the truths of faith. For, if philosophy, or logical reasoning, is “reflection upon existing things…insofar as they are an indication of the Artisan,” and “if the Law has recommended and urged consideration of existing things,” it follows that philosophy “is either obligatory or recommended by the Law.”:”(Decisive Treatise, pp. 1-2.)”: Averroes provides a handful of texts which show that the Law has required this.
Averroes argues that since we accept demonstrations in astronomy, mathematics, and jurisprudence, and we cannot expect to discover everything on our own, we must consider the works of the Ancients who have blazed these trails. Intellectual “tools” (i.e., reason) are neutral with respect to religious belief, so those Muslims who call philosophy “innovation” or “heresy” are mistaken.:”(Ibid., pp. 4-7.)”: He who forbids reflection on the books of the Ancients “bars people from the door through which the Law calls them to cognizance of God.” Regarding those who use philosophy and go astray, Averroes holds a principle similar to the Latin abusus non tollit usus: “it is not obligatory to renounce something useful in its nature and essence because of something harmful in it by accident.”:”(Ibid., pg. 7.)”:
To further defend rational demonstration, Averroes mentions three modes of cognizing God, the dialectical, the rhetorical, and the demonstrative, and focuses on the third. Demonstration does not contradict the Law, for “truth does not oppose truth; rather, it agrees with and bears witness to it.” Again, Law-based syllogistic reasoning is accepted by Muslims in jurisprudence, so it is only fitting that it apply to theology.
Once syllogistic reasoning is applied to the Law, a distinction between the “apparent” and “inner” senses of the Law emerges. People differ in their capacities for assent, so variances arise between the Law and demonstration. This requires interpretation, and Averroes distinguishes theoretical (which most don’t need to know) from practical (which all should know) matters. The interpretation of theoretical matters is carefully governed by a set of clear rules.:”(Ibid., pg. 9-11.)”:
Averroes denies that the philosophers are heretics on the matters of (1) God’s knowledge of particulars, (2) the eternity of the world, and (3) the resurrection of the body and the afterlife. This charge fails to distinguish faith that is well-grounded in science from faith that is not based on demonstration. Errors made on the level of the apparent sense of the Law are unbelief, while errors made in interpretation, even by those trained to interpret, are excusable. It is dangerous to put interpretations before the eyes of those not trained to navigate them; this was Al-Ghazali’s error.:”(Ibid., pp. 12-21.)”:
Finally, Averroes discusses how the Law teaches “true cognizance” of God. Most of the Law takes the form of the dialectical and rhetorical, because only few can follow the demonstrative. Failure to recognize this, and declaring interpretations to all without respecting ability to understand, has led to the creation of factions within Islam. These factions may be removed by striving, wherever possible, for the sense that is apparent to all and leaving interpretation to those qualified to engage in it.:”(Ibid., pp. 22-33.)”:
In these ways, Averroes gave his “decisive” answer to the major philosophical-theological problems of his day, and provided much food for thought for later thinkers.