The paper explores John Rawls´s idea of public reason, as reflected in Political Liberalism
and The Idea of Public Reason Revisited. In Rawls’s later works, public reason acquires
fundamental significance as a criterion by which the principles to be assumed from the
outset in a theory of political justice may be determined. The starting-point for Rawls´s
theory -the idea of citizens as free and equal reveals- that this abstraction falls short of an
authentic conception of human beings as social by nature. A brief study of key issues
concerning marriage and the family shows the difficulties that underlie this question. The
paper also offers a concise overview of some of the principles of Natural Law Theory. In
this context, a theory of political liberalism and justice might be upheld by drawing
natural law and public reason into close correlation, thus safeguarding the substantive
human goods necessary in society.
