Discourse ethics, sometimes called "argumentation ethics", refers to a type of argument that attempts to establish normative or ethical truths by examining the presuppositions of discourse.
Habermas's discourse ethics (1990) is his attempt to explain the implications of communicative rationality in the sphere of moral insight and normative validity. It is a complex theoretical effort to reformulate the fundamental insights of Kantian deontological ethics in terms of the analysis of communicative structures. This means that it is an attempt to explain the universal and obligatory nature of morality by evoking the universal obligations of communicative rationality. It is also a cognitivist moral theory, which means it holds that justifying the validity of moral norms can be done in a manner analogous to the justification of facts. However, the entire project is undertaken as a rational reconstruction of moral insight. It claims only to reconstruct the implicit normative orientations that guide individuals and it claims to access these through an analysis of communication.
Habermas maintains that normative validity cannot be understood as separate from the argumentative procedures used in everyday practice, such as those used to resolve issues concerning the legitimacy of actions and the validity of the norms governing interactions.
He makes this claim by making reference to the validity dimensions attached to speech acts in communication and the implicit forms of argumentation they imply (see Universal pragmatics). The basic idea is that the validity of a moral norm cannot be justified in the mind of an isolated individual reflecting on the world. The validity of a norm is justified only intersubjectively in processes of argumentation between individuals; in a dialectic. The validity of a claim to normative rightness depends upon the mutual understanding achieved by individuals in argument.
From this it follows that the presuppositions of argumentation would become important. Kant extracted moral principles from the necessities forced upon a rational subject reflecting on the world. Habermas extracts moral principles from the necessities forced upon individuals engaged in the discursive justification of validity claims, from the inescapable presuppositions of communication and argumentation. These presuppositions were the kinds of idealization that individuals had to make in order for communication and argumentation to even begin. For example:
There were also presuppositions unique to discourse:
These are all at the center of Habermas's moral theory. Habermas's discourse ethics attempts to distill the idealized moral point of view that accompanies a perfectly rational process of argumentation (also idealized), which would be the moral principle implied by the presuppositions listed above. The key point is that the presuppositions of argumentation and communication that have been rationally reconstructed by Habermas are both factual and normative. This can be said about his entire project because it is explicitly attempting to bridge the gap between the "is" and the "ought". Habermas speaks of the mutual recognition and exchanging of roles and perspectives that are demanded by the very structural condition of rational argumentation. He maintains that what is implied in these factual presuppositions of communication is the deep structure of moral norms, the conditions that every valid norm must fulfill. The presuppositions of communication express a universal obligation to maintain impartial judgment in discourse, which constrains all affected to adopt the perspectives of all others in the exchange of reasons. From this Habermas extracts the following principle of universalization (U), which is the condition every valid norm has to fulfill:
This can be understood as the deep structure of all acceptable moral norms, and should not be confused with the principle of discourse ethics (D), which presupposes that norms exist that satisfy the conditions specified by (U).
The implications of (U) and (D) are quite profound. (U) claims to be a rational reconstruction of the impartial moral point of view at the heart of all cognitivist moral theories. According to moral cognitivists (e.g. Kant, Rawls etc.), it is only from such a moral point of view that insight into the actual (quasi-factual) impersonal obligations of a general will can be gained, because this perspective relieves decisions from the inaccuracies of personal interests. Of course, Habermas's reconstruction is different because it is intersubjective. That is, Habermas (unlike Kant or Rawls) formulates the moral point of view as it arises out of the multiple perspectives of those affected by a norm under consideration. The moral point of view explicated in (U) is not the property of an individual subject but the property of a community of interlocutors, the results of a complex dialogical process of role taking and perspective exchanging. Furthermore, (U) is deduced from a rational reconstruction of the presupposition of communication, which downgrades the strong transcendentalism of Kantian ethics by establishing a foundation in inner-worldly processes of communication. (D) on the other hand is a principle concerning the manner in which norms conforming to (U) must be justified though discourse. Again, Habermas takes the task of moral reflection out of the isolated individual's head and gives it to intersubjective processes of communication. What (D) proposes is that moral principles must be validated in actual discourse and that those to be affected by a norm must be able to participate in argumentation concerning its validity. No number of thought experiments can replace a communicative exchange with others regarding moral norms that will affect them. Moreover, this general prescription concerning the type of discourse necessary for the justification of moral norms opens the process of moral deliberation to the kind of learning that accompanies a fallibilistic orientation. (U) and (D) are catalysts for a moral learning process, which although fallible is not relative. The flesh and blood insights of participants in communicative exchange are refracted through the universal guidelines explicated from the deep structures of communication and argumentation. This spawns discourses with a rational trajectory, which are grounded in the particular circumstances of those involved but aimed at a universal moral validity.
See, e.g., Jürgen Habermas, "Discourse Ethics: Notes on a Program of Philosophical Justification," and Karl-Otto Apel, "Is the Ethics of the Ideal Communication Community a Utopia? On the Relationship between Ethics, Utopia, and the Critique of Utopia," both in The Communicative Ethics Controversy, Seyla Benhabib and Fred Dallmayr, eds. (Cambridge, Mass.: MIT Press, 1990).
Hans-Hermann Hoppe's "argumentation ethics" is a defense of libertarian rights. Hoppe, drawing on the work of Habermas and Apel (and a former student of Habermas's), argues that because argumentation, or discourse, is by its nature a conflict-free way of interacting, and requires individual control of resources in order to argue and be alive to do so, that certain norms are presupposed as true by anyone engaging in genuine discourse. These norms include the libertarian principle of non-aggression, which itself implies libertarian rights. Therefore, no one can argumentatively deny libertarian rights without self-contradiction.
Gary B. Madison's views are similar to Hoppe's argumentation ethics approach and also draw on Habermasian discourse ethics. Madison argues that
the various values defended by liberalism are not arbitrary, a matter of mere personal preference, nor do they derive from some natural law. . . . Rather, they are nothing less and nothing more than what could be called the operative presuppositions or intrinsic features and demands of communicative rationality itself. In other words, they are values that are implicitly recognized and affirmed by everyone by the very fact of their engaging in communicative reason. This amounts to saying that no one can rationally deny them without at the same time denying reason, without self-contradiction, without in fact abandoning all attempts to persuade the other and to reach agreement. (Madison, 1986)
These implicitly recognized values include a renunciation of the legitimacy of violence. Thus,
it is absolutely impossible for anyone who claims to be rational, which is to say human, outrightly to defend violence .... [As Paul Ricoeur writes:]'. . . violence is the opposite of discourse. . . . Violence is always the interruption of discourse: discourse is always the interruption of violence.' That violence is the opposite of discourse means that it can never justify itself—and is therefore not justifiable—for only through discourse can anything be justified. As the theory of rational argumentation and discussion, liberalism amounts, therefore, to a rejection of power politics.
Thus, Madison, like Hoppe, argues that the fact-value gap can be bridged by an appeal to the nature of discourse.
[T]he notion of universal human rights and liberties is not an . . . arbitrary value, a matter of mere personal preference. . . . On the contrary, it is nothing less and nothing more than the operative presupposition or intrinsic feature and demand of communicative rationality itself.
While Hoppe attempts to show that the non-aggression principle (i.e., self-ownership plus the right to homestead) itself is directly implied by any discourse or argumentation, Madison's arguments are a bit different. For instance, he argues that, because discourse has priority over violence, this validates the Kantian claim that people ought to be treated as ends rather than means, which is the principle of human dignity. The principle of freedom from coercion then follows from the principle of human dignity.
The "estoppel" theory of Stephan Kinsella draws on Hoppe's theory. Kinsella argues that an aggressor cannot coherently object to being punished for the act of aggression, by the victim or the victim's agents or heirs, i.e. he is "estopped" from withholding consent, because by committing aggression he commits himself to the proposition that the use of force is legitimate, and therefore, his withholding consent based on his right not to be physically harmed contradicts his aggressive legitimation of force.
In a theory bearing some resemblance to Kinsella's estoppel theory, law professor Lawrence Crocker proposes the use of moral estoppel in preventing a criminal from asserting the unfairness of being punished in certain situations. Crocker's theory, while interesting, is not rigorous, and Crocker does not seem to realize the implications of estoppel for justifying only the libertarian conception of rights. Rather than focusing on the reciprocity between the force used in punishment and the force of an aggressive act by a wrongdoer, Crocker claims that a person who has "treated another person or the society at large in a fashion that the criminal law prohibits" is "morally estopped" from asserting that his punishment would be unfair. Crocker's theory is not quite libertarian, however, since it seems to assume that any law is valid, even those that do not prohibit the initiation of force. (Crocker, 1992)
Flemish law professor Frank van Dun suggests that part of "the ethics of dialogue" is that we ought to respect the "dialogical rights of others—their right to speak or not to speak, to listen or not to listen, to use their own judgment." Van Dun even suggests that "principles of private property and uncoerced exchange" are also presupposed by participants in discourse.
Philosopher Jeremy Shearmur also proposes that an argument about 'dialogue rights' which draws on themes from Hayek and Karl Popper may be developed to justify individual property rights and other classical liberal principles, in an argument different in approach from that of Hoppe, Madison, and van Dun.
Other theories bearing some resemblance to discourse ethics include Paul Chevigny's theory that the nature of discourse may be used to defend the right to free speech and Tibor Machan's view that discourse in general and political dialogue in particular rest on individualist prerequisites or presuppositions. However, Machan, accepting the validity of action-based ethical theories (similar to Pilon's and Gewirth's approach, discussed below), but not purely-argumentation-based theories, also maintains that "human action needs to be understood by reference to human nature."
In addition, Rodney J. Blackman defends a procedural natural-law position on the grounds that, as we normally use language and define "law," "law" has a procedural component that, if adhered to, limits a government's arbitrary and irrational use of power. Blackman contends that language users implicitly accept this normative, procedural aspect of what is described as law; they use a definition of law that also limits what state power can be classified as law. (Blackman, 1995)
A somewhat similar argument is made by noted libertarian law professor and legal theorist Randy E. Barnett. Professor Barnett argues that those who claim that the U.S. Constitution justifies certain government regulation of individuals are themselves introducing normative claims into discourse, and thus cannot object, on positivist or wertfrei grounds, to a moral or normative criticism of their position.
Libertarian legal philosopher Roger Pilon has also developed a libertarian version of the rights theory of his teacher, noted philosopher Alan Gewirth. Although he disagrees with the non-libertarian conclusions that Gewirth himself draws from his own rights theory, Pilon builds "upon much of the justificatory groundwork he has established, for I believe he [Gewirth] has located, drawn together, and solved some of the most basic problems in the theory of rights." (Pilon, 1979, p. 1173)
To determine what rights we have, Pilon (following Gewirth) focuses on "what it is we necessarily claim about ourselves, if only implicitly, when we act." (Pilon, 1979, p. 1177). Pilon argues that all action is conative, that is, an agent acts voluntarily and for purposes which seem good to him. Pilon argues that the prerequisites of successful action are "voluntariness and purposiveness," the so-called "generic features" that characterize all action. Thus an agent cannot help valuing these generic features and even making a rights-claim to them, according to Pilon/Gewirth. From this conclusion, it is argued that all agents also necessarily claim rights against coercion and harm. And since it would be inconsistent to maintain that one has rights for these reasons without also admitting that others have these rights too (since the reasoning concerning the nature of action applies equally to all purposive actors), such rights-claims must be universalizable. Thus, an agent in any action makes a rights-claim to be free from coercion and harm, since such rights are necessary to provide for the generic features of action, which an agent also necessarily values, and the agent also necessarily grants these rights to others because of the universalizability requirement.
From this point, Pilon/Gewirth develops a sort of modern Categorical Imperative, which is called the "Principle of Generic Consistency" (PGC). The PGC is: "Act in accord with the generic rights of your recipients as well as of yourself." ("Recipients are those who stand opposite agents, who are 'affected by' or 'recipients of' their actions.") (1979, p. 1184). Under Pilon's libertarian working of the PGC, the PGC does not require anyone to do anything. It is addressed to agents, but it does not require anyone to be an agent who has recipients. An individual can "do nothing" if he chooses, spending his life in idle contemplation. Provided there are no recipients of this behavior, he is at perfect liberty to perform it. And if there are recipients, the PGC requires only that he act in accord with the generic rights of those recipients, i.e., that he not coerce or harm them. (1979, p. 1184). Pilon extends his reasoning and works the PGC to flesh out more fully just what (primarily libertarian) rights we do have.