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Argumentation ethics, is a libertarian political theory first described in 1988 by philosopher and economist Hans-Hermann Hoppe, a University of Nevada, Las Vegas Professor Emeritus and Ludwig von Mises Institute Senior Fellow. Hoppe says his theory proves that arguing for any political position other than libertarian anarchism is logically inconsistent. He describes his argument as a strictly logical, value-free consequence of sound deductive reasoning. Most responses have come from Hoppe's libertarian anarchist colleagues at the Ludwig von Mises Institute.
Hoppe states that his theory is an a priori, value-free praxeological argument for deontological libertarian ethics. Argumentation ethics asserts the non-aggression principle is a presupposition of every argument and so cannot be logically denied during an argument. Argumentation ethics draws on ideas from Jürgen Habermas's and Karl-Otto Apel's discourse ethics, from Misesian praxeology and from the political philosophy of Murray Rothbard.
Hoppe first notes that when two parties are in conflict with one another, they can choose to resolve the conflict by engaging in violence, or engaging in argumentation. In the event that they choose to engage in argumentation, Hoppe asserts that the parties have implicitly rejected violence as a way to resolve their conflict. He therefore concludes that non-violence is an underlying norm (Grundnorm) of argumentation, that is accepted by both parties.
Hoppe states that, because both parties propound propositions in the course of argumentation, and because argumentation presupposes various norms including non-violence, the act of propounding a proposition that negates the presupposed propositions of argumentation is a logical contradiction between one's actions and one's words (this is called a performative contradiction). Specifically, to argue that violence should be used to resolve conflicts (instead of argumentation) is a performative contradiction.
Non-aggression principle 
Argumentation ethics aims to show the non-aggression principle follows from the non-violence presupposition of argumentation, and so it cannot be denied.
If violence is not a norm that can be logically justified in argumentation as a way to resolve a conflict, Hoppe asks which norms can indeed be justified in argumentation. Hoppe first argues that only universal norms are consistent with argumentation, as arbitrary categorical distinctions have no intersubjective justification. Hoppe then argues that since argumentation requires the active use of one's body, all universal norms for resolving conflicts over the human body aside from self-ownership are inconsistent with argumentation. Hoppe then argues that since the resolution of conflicts over external resources must also be objectively justifiable, only the physical establishment of an objective link by original appropriation (i.e., homesteading) is a norm compatible with argumentation. From these Hoppe concludes that only the non-aggression principle of self ownership and Lockean homesteading can be justified in an argument without contradiction.
Punishment and self-defense 
Bearing reference to the legal doctrine of estoppel, Stephan Kinsella's "Dialogical Estoppel" theory extends argumentation ethics by considering an argument between a victim and aggressor. Kinsella argues that an aggressor cannot consistently object to being proportionally punished for his act of aggression, by the victim or by the victim's representatives, because by committing aggression he commits himself to the proposition that the use of force is legitimate, and therefore, his withholding consent based on a normative right not to be physically harmed contradicts his aggressive legitimation of force, i.e. he is "estopped" from withholding consent.
Intellectual property 
Argumentation ethics is incompatible with intellectual property, as it defines property rights over concepts, which are inherently non-scarce. Property rights in non-scarce, superabundant goods are not conflict avoiding but rather conflict seeking. Furthermore since concepts are abstractions no objective conflict over their use can arise.
Various responses to Hoppe's argument came from Hoppe's colleagues at the Ludwig von Mises Institute. Some of them accepted his argument, among them attorney Kinsella and economists Walter Block and Murray Rothbard, who called it "a dazzling breakthrough for political philosophy in general and for libertarianism in particular," adding "he has managed to transcend the famous is/ought, fact/value dichotomy that has plagued philosophy since the days of the Scholastics..."
Mises Institute economists Bob Murphy and Gene Callahan rejected Hoppe's argument. The late Austrian Economist David Osterfield, an adjunct scholar at the Mises Institute, also rejected Hoppe's argument in an essay to which Hoppe subsequently responded.
Ludwig Von Mises Institute Senior Fellow and Auburn University philosopher Roderick Long reconstructed the argument in deductively valid form, specifying four premises on whose truth the argument's soundness depends. Long goes on to argue that each premise is either uncertain, doubtful, or clearly false. He summarizes his views by stating:
I don’t think there’s any reason to reject out of hand the kind of argument that Hoppe tries to give; on the contrary, the idea that there might be some deep connection between libertarian rights and the requirements of rational discourse is one I find attractive and eminently plausible. [...] But I am not convinced that the specific argument Hoppe gives us is successful.
See also 
- Hoppe, Hans-Hermann; Murray N. Rothbard, David Friedman, Leland Yeager, David Gordon, Douglas Rasmussen (November 1988). "Liberty Symposium". Liberty 2.
- Kinsella, Stephan (March 13, 2009). "Revisiting Argumentation Ethics". Mises Economics Blog. Ludwig von Mises Institute. "[A] number of thinkers weighed in, including Rothbard, ... Conway, ... D. Friedman, ... Machan, ... Lomasky, ... Yeager, ...Rasmussen, and others...."
- Hoppe, Hans-Hermann (20 May 2002). "Rothbardian Ethics". LewRockwell.com. Retrieved 6 February 2012.
- The Ultimate Justification of the Private Property Ethic. Hans Hoppe
- Punishment and Proportionality: The Estoppel Approach. N.S. Kinsella
- Hoppe, Hans-Hermann, 1988 panel discussion
Question: Does the idea of personal sovereignty extend to knowledge? Am I sovereign over my thoughts, ideas, and theories? Hoppe: ... in order to have a thought you must have property rights over your body. That doesn’t imply that you own your thoughts. The thoughts can be used by anybody who is capable of understanding them.
- Kinsella, Stephan (Spring 2001). "Against Intellectual Property". Journal of Libertarian Studies 15 (2).
- Kinsella, Stephan (19 September 2002). "Defending Argumentation Ethics: Reply to Murphy & Callahan". Anti-State.com. Retrieved 9 February 2012.
- Rothbard, Murray N. (Article originally appeared in Liberty (November 1988)). "Beyond Is and Ought". Mises.org. Retrieved 14 October 2012.
- Murphy, Robert P.; Callahan, Gene (Spring 2006). "Hans-Hermann Hoppe's Argumentation Ethics: A Critique". Journal of Libertarian Studies 20 (2): 53–6. Retrieved 9 February 2012.
- "Comment on Hoppe / Comment on Osterfeld". Austrian Economics Newsletter. 1988. Retrieved 14 October 2012.
- Long, Roderick T.. "The Hopperiori Argument".
Further reading 
- Van Dun, Frank (January 1, 2009). "Argumentation ethics and the philosophy of freedom". Libertarian Papers. Retrieved May 8, 2013 from Highbeam Research.
- Argumentation Ethics and Liberty: A Concise Guide
- Collection of publications regarding argumentation ethics
- The A priori of Argumention, video introduction by Hoppe
- The Social Theory of Hoppe, on-line course by Stephan Kinsella.
- Eabrasu, Marian (2009). "A Reply to the Current Critiques Formulated Against Hoppe's Argumentation Ethics". Libertarian Papers 1.