Rational and irrational tendencies have competed vigorously in legal thought in both Western and Islamic traditions. In Western tradition, the competition took place within the internal rational natural law school, as indicated by the split of this school into the irrational natural law school and the rational natural law school. In Islam, similar competition divided Muslim jurists into the traditionalists (ahl al-hadith) and rationalists (ahl al-ra'y). Within the Western tradition, the conflict continues and no compromise appears, while in Islam, irrational tendencies and rational tendencies have reached certain compromises. This article, using philosophical approach, seeks to find out the factors causing the failure of such compromises in the Western tradition and the achievement of such compromises in Islamic tradition. This article concludes that the conflict within natural law is more substantial and it denies any effort of compromises as it concerns with the very nature of law and its authoritative sources, whereas in Islam, basically, the disputes are merely about the methodological aspects, i.e. the methods of inferring the law from its shared sources.