Beyond Religious Borders: Interaction and Intellectual Exchange in the Medieval Islamic World

Chapter 8: The Impact of Interreligious Polemic on Medieval Philosophy

c h A p t e r 8 The Impact of Interreligious Polemic on Medieval Philosophy dAnIel J. l Asker One of the outstanding characteristics of the academic study of Jewish philosophy from its very inception in the nineteenth century has been the search for the non-Jewish sources employed by medieval Jewish philosophers.1 Most scholars have assumed that Islamic philosophy was the most significant influence on medieval Jewish philosophy, but in the last few decades students of the field have made increasing efforts to expand the corpus of sources.2 Thus, some scholars have recently turned to the non-philosophical internal Jewish sources of Jewish philosophers,3 while still others have investigated external influences on Christian and Islamic philosophy.4 Diana Lobel’s excellent and learned study of Baḥya ibn Paqūda’s Duties of the Heart, entitled A Sufi-Jewish Dialogue,5 provides a good example of the attempt to marshal the wealth of sources, Jewish and non-Jewish, philosophical and non-philosophical, that underlie a prominent Jewish philosophical/moral treatise. Let us look, for instance, at the chapter devoted to divine unity. Lobel illustrates what she calls the various crosscurrents that contributed to Baḥya’s discussion of God’s oneness: Jewish monotheism, Pythagorean and Neoplatonic number mysticism, the philosophical distinctions between the True One and the metaphorical one, and Sufi mystical devotion. She cites authors as diverse as Saadia ben Joseph Gaon, Isaac Israeli, and Solomon ibn Gabirol among the Jews; al-Naẓẓām, al-Ashʿarī, and Shahrastānī among the Islamic mutakallimūn; Yaʿqūb al-Kindī and Avicenna among the Islamic Aristotelians; and Ikhwān al- Ṣafāʾ, Thābit ibn Qurra, Qushayrī the Sufi, and Baṭalyawsī among other Muslim 116 dAnIel J. l Ask er scholars. Despite Lobel’s impressive erudition, however, one complete genre is missing from her discussion: the literature of the Jewish-Christian-Islamic debate , which has, not surprisingly, a great deal to contribute to an understanding of Baḥya’s view of divine unity. In Lobel’s discussion of divine unity, al-Kindī’s First Philosophy is cited at length, but his refutation of the Trinity, known from the counterrefutation by Yaḥyā ibn ʿAdī, is not mentioned; Ibn Gabirol’s distinctions in Keter Malkhut between various kinds of unity are adduced; and Dāwūd al-Muqammaṣ’s much more detailed analysis and the Karaite Yaʿqūb al-Qirqisānī’s adaptation of it are missing, even though al-Muqammaṣ is specifically mentioned by Baḥya in his introduction to Duties of the Heart, and Lobel does cite him in her discussion of divine attributes. No reference is made to any Christians, such as Nonnus of Nisibis, Ḥabīb ibn Ḥidma abū Rāʾiṭa, or Yaḥyā ibn ʿAdī, despite their relevance to the discussion.6 The example of Diana Lobel’s book is a particularly good one because of its overall high quality. Her work illustrates the predominant trend in the historical analysis of medieval philosophy: a close exploration of internal and external philosophical sources (and, in this case, mystical sources) without any discussion of the decisive impact of interreligious polemic on philosophical discussions . I will argue here that a close reading of the controversial literature indicates that quite a number of developments in medieval philosophical discourse can actually be traced to polemical motivations. The discussion here will review the impact of polemics on the following philosophical topics as they developed particularly in the Islamic realm: epistemology, the nature of God, and theodicy. The majority of the discussion below treats the impact of polemics on Jewish philosophy. Nonetheless, it is clear that interreligious polemic also made a significant impact on Islamic and Christian thought and that philosophy and polemics are intertwined in all three religious traditions. * * * Let us start with epistemology. The philosopher’s first problem, whether she believes in God and is a member of a faith community or whether he is an avowed atheist, is: How do we know? This question is sharpened by a conflict of truth claims, especially when the divergent truth claims have their origin neither in perception nor in intellection but in the assumption of divine revelation. Interreligious Polemic 117 Most philosophers are willing to consider knowledge attained through the use of either sense perception or reason as valid for all human beings. In contrast, however, Jews, Christians, and Muslims claim to have...