Rhetorical argumentation focuses on persuasion, adherence, communion, consensus, co-construction… These terms sound much like moral incitements, “don’t be different, be the same”; and it’s difficult to disagree with the principle of agreement. The emphasis on persuasion and consensus suggests that unanimity would be the normal, healthy state of society, as opposed to the pathological state of controversy, or dissensus.
1. The passion for dissensus as sin and fallacy
The passion for dissensus characterizes polemical exchanges; verbal violence is not associated with controversies as it is with polemics. Emotional dramatization and personal involvement are expressed in the speech acts opening the debate: to rise up against, to be outraged, to protest… When it comes to emotional repercussions, controversy and polemic might hurt the feelings of the parties.
The polemicist refuses to close the debate, and allow the other party’s argument to prevail, even if it is the stronger argument. This refusal to defer to the arguments of the other is a paralogism of obstinacy, stigmatized by Rule 9 of the critical discussion, that asks the proponent to bow before a conclusive argument (van Eemeren & Grootendorst 2004, p. 195; S. Rules). But who says that the point of view has been conclusively defended? The polemicist refuses to admit that the point of view of his or her opponent has been defended conclusively, and posits that the veracity of his or her viewpoint is beyond reasonable doubt. As a last resort, he or she might appeal to intimate conviction, as a way of preserving a jeopardized identity.
The condemnation of argumentativeness and polemic has deep historical roots. The Middle Ages considered contentio, that is contentiousness, as a sin of the tongue, S. Fallacies as Sins.
Contentio is a war of words. It may be a defensive war waged by the stubborn individual, who refuses without reason alter his position. But contentio is most often manifested as a display of aggression in one of many forms. This might be an unnecessary verbal attack against one’s neighbor, an aim not to seek the truth, but to simply manifest aggression (Aymon); a quarrel which, abandoning any quest for truth, gives rise to dispute and goes as far as blasphemy (Isidore); a refined and malevolent argumentation that opposes the truth to satisfy an irresistible desire for victory (Glossa ordinaria); a wicked, contentious and violent altercation (Vincent of Beauvais); an attack against the truth led by the strength of the clamor [“public outcry”, CP] (Glossa ordinaria, Peter Lombard). Often, however, the contentio appears in texts without ever being defined, as if the connotation of violent verbal antagonism attached to the term is sufficient to indicate that it should be avoided and condemned as a sin. (Casagrande & Vecchio (, p. 213-214)
Contentio is a second level sin, derived from first level sins such as envy, vainglory and pride. There is one reservation to be mentioned here, namely that such definitions restrict the sin of contentio to violent attacks against religious truth. It is not, however, a sin to violently and continuously attack error and sin; anger becomes a holy anger.
2. Polemics and “deep disagreement”
The concept of deep disagreement was introduced by Fogelin (1985). Deep disagreement involves incompatible values or metaphysical principles, rather than empirically testable epistemic issues. The solution of scientific conflicts, including in mathematics and logic, call for technical treatment (Woods 2003), while deep disagreement is more akin to polemics, involving intense personal commitment on the part of the participants. Nonetheless, polemics seems to prefer (face-to-face) confrontation, while deeply disagreeing position can be developed in parallel and in mutual ignorance, thus appearing beyond the field of argued dialogue.
In human affairs, the existence of such intractable divergences may be considered as a “radically shocking” challenge (Turner & Campolo 2005, p. 1) to the argumentative enterprise itself. “if [Fogelin] was right, what would become of the field? Even more important, arguably, what could be done about deep disagreements themselves? The field and all of the good it meant to accomplish seemed to be threatened all at once” (ibid.).
3. The post-persuasion era and the normality of dissensus
Any serious argumentative debate contains an element of radicalism, which calls for a de-demonization of dissensus, and, as a consequence, for a re-evaluation of the role of the ratified third parties, who have the power to make a decision. As Willard, who has written extensively on this subject, states:
To prize dissensus goes against an older tradition in argumentation, that values opposition less than the rules that constrain it. (Willard 1989, p. 149)
The preference for consensus does not exclude the reality of dissensus. Argumentation studies must confront situations in which differences of opinion are produced, managed, solved, amplified or transformed through their discursive confrontation. Determining which differences of opinion should be reduced and how, and which ones should rather be encouraged and deepened is a major social and scientific issue, having critical educational implications.
Argumentation can be used to divide opinion; this is what the discourse of Christ achieves in the Christian vision of the world:
Do not suppose that I have come to bring peace to the earth. I did not come to bring peace, but a sword. 35 For I have come to turn a man against his father, a daughter against her mother, a daughter-in-law against her mother-in-law, a man’s enemies will be the members of his own household. Matthew 10: 34-36
The first virtue of argumentation is not that it solves the conflicts, but that it is able to give words to conflicts; it is a precious method of managing differences, sometimes reducing them, sometimes increasing them and causing them to multiply. In an over-consensual context, it may be the noble task of argumentation to bring about relevant dissensual discourses, and to value and stimulate the emergence of differences of opinion.
The majority rule does not imply that the majority is the holder of the truth, and is entitled to enforce its rule over a disgraced minority who spuriously resist the persuasive power of the orator, or refuse to acknowledge the defeat inflicted upon them by the dialectician. One can hypothesize that, in our terrestrial world, the coexistence of contradictory opinions represents the normal state, neither pathological nor transitory, of the socio-political ideological field; deep disagreement is the routine and rule. Hegelians would add that contradiction is the dialectical engine of history.
In any case, democracy does not eliminate differences, and voting does not eliminate minorities and their opinions. In such conditions “it is not about convincing, but about living together” , the objective is not to convince others, but to enable groups to coexist. Argument is a way of managing these differences, sometimes eliminating them, sometimes promoting them for the common good.
 Matthew 10:34-36. Quoted after The Bible, New International Version (NIV), www.biblegateway.com/passage/?search=Matthew%2010:34-36 (11-08-2017)
 “No se trata de convencer sino de convivir”. A. Ortega, “La razón razonable”, El País, 25-09-2006.