This thesis is a study on the notion of practical rationality. Its main objective is to explore whether there is a shared way of reasoning in practical and moral issues between different cultures and traditions. For this purpose, I chose MacIntyre's notion of tradition-constituted and tradition-constitutive rationality and justice (constitution thesis) as the key topic of the thesis, which holds there is no rationality and justice independent of a tradition. Rationality here is mainly practical rationality a most important outcome of which is the idea of justice. We can understand MacIntyre's constitution thesis in contrast to Cartesian epistemology and Kant's moral philosophy as they are understood by him. The constitution thesis runs counter to Cartesian epistemology by its anti-epistemological tendencies; that is to say, we do not and cannot start our substantial intellectual enquiries based on some indubitable ideas whose evidence can be shown to any rational human being. The constitution thesis runs also counter to Kantian moral philosophy by its opposition to providing a universalistic rule-based account of morality. The constitution thesis in this sense is related to virtue-ethics which emphasizes the importance of moral education and following moral masters for knowing moral duties. I will argue that we can have an account of morality that does not depend on the notion of the final good; rather, it assumes basic facts about human beings, which include their basic and intellectual needs the failure to satisfy which damages their normal and desirable functioning. The mark of real needs is that their satisfaction sustains and improves our normal and desirable functioning, and this point lets us distinguish real needs from our acquired desires and expectations. This would be against MacIntyre's claim that the justification of morality requires the notion of the human good
