A sound lifestyle depends on doctrinal and philosophical principles such as rationality, spirituality, moderation and the like. With Western scholars, rationality is interpreted as a means for meeting material needs, capitalism, negation of metaphysical power, opposing religion and religious devotion; therefore, it cannot be used as the foundation for a sound religious lifestyle. However, were rationality regarded transcendent and comprehensive, it would lead to a progress in all dimensions of individual and social lifestyle thus to the realization of Islamic civilization. 
    In their paper, the authors have explained transcendent rationality and its deference from current rationalities. The characteristics of such rationality are clarified at three levels. At the cognitive level, they are: maximum use of the sources of knowledge, truth-centeredness, security, peace and certainty, the authority of logical rules, consideration of well-founded science-data, the choice of best explanation, reliance on self-evident knowledge, and demarcating borders between the scope of experience and the revealed and philosophical teachings. At the moral level, they are: a wide system of values, internal coherence, capability of rational explanation, considering both good act and good intention of the agent, and that the system of values is hierarchical. At the instrumental level and livelihood, they are: purposefulness, the choice of proper means for aims, the choice of rationality in the case of different probabilities, considering the expected profits, and moderation. The adopted method is analytic-descriptive.