The aim of this paper is to propose a model for understanding the relation between substance and procedure in discourse ethics and deliberative democracy capable of answering the common charge that they involve an ‘empty formalism’. The expressive-elaboration model introduced here answers this concern by arguing that the deliberative practical rationality presupposed by discourse ethics and deliberative democracy involves the creation of a practical medium in which certain general basic ideas of solidarity, equality and freedom are expressed and elaborated in (...) the context of widespread moral disagreement. In the course of this paper I propose an elucidation of these ideas and argue for the thesis that they are internally related to the endorsement of deliberative practical rationality. The three basic substantive ideas contribute to the determination of the existence, the form, the topics and intended outcomes, and the effects of the practice of public deliberation. This amounts to an elucidatory defense of deliberative practical rationality by explicating its substantive significance or point. Key Words: critical theory • deliberative democracy • discourse ethics • equality • freedom • Jürgen Habermas • practical reason • John Rawls • solidarity • substance and procedure. (shrink)