Three main types of debates have been identified by our research on historical cases of intellectual confrontations in philosophy, science, and theology: discussions, disputes, and controversies. Summary presentation of this trichotomy. The three categories are ideal types, in the Weberian sense, i.e., actual debates may exemplify different combinations of elements of each of them.

A presumption is a non-monotonic rule of inference that justifies a conclusion, unless there are good reasons to overthrow it. Presumptions figure prominently in all kinds of debate, for they have the effect of distributing unevenly the onus probandi. Naturally, any contender in a debate will be interested in counting with the support of a favorable presumption. In case the current presumption is not favorable to his position, s/he will usually try to replace it by a favorable one. There are two ways in which a presumption can be challenged: (a) by contesting the conclusion; (b) by contesting the rule itself. A discussion is typically a case of type (a). A controversy is typically a case of type (b). In both cases the challenger argues in support of his/her challenge, thus seeking to rationally persuade his/her opponent or a relevant audience. In a typical dispute, each contender is persuaded that s/he is right, whatever the arguments of the opponent; hence, their basic conviction can hardly be seen as a presumption, for it seems to exclude the very possibility of its violation (a) or of its modification (b); the role of argumentation in disputes, therefore, is typically restricted to an eristic function. For this reason, whereas disputes may be viewed as largely “irrational”, discussions and controversies can be considered “rational”, albeit in different ways.

Debates are communicative exchanges that evolve in time. Their minimal unit consists in a full set of four communicative “turns”, where at least two “speakers” – a ponens (P) and an opponens (O) – intervene in a P-O-P-O pattern.

Important debates usually extend beyond this minimal unit, through further interventions of P and O or of other participants. Such an extension can go beyond a single generation, especially in philosophical debates. The longer its temporal extension, the more a debate is likely to evolve thematically and argumentatively. Nevertheless, some debates can remain, over their many “rounds”, narrowly focused on the initial issue that sparked them, while in others one may observe significant thematic shifts that lead far away from the original issue. In such cases, the criteria for the identification of the debate are not always precise, and may require the elaboration of rather vague notions such as that of “thematic affinity” or “family resemblance”.

Discussions, disputes, and controversies differ in their inner dynamic behavior, especially regarding their thematic expansion (and consequently their temporal extension). Both discussions and disputes tend to remain narrowly focused on the specific issue that triggers them, whereas controversies are characterized by broad thematic shifts, involving both the object- and the meta-level.

Debates are not static in another important respect: they can shift from one of the three ideal types to another. Such shifts are recognizable through changes in the issues debated, as well as in the argumentative strategies or rhetoric employed. Thus, a discussion may evolve into a controversy when the contenders begin to question each other’s presumptions, and into a dispute when they see in such questioning a sign of the opponent’s irrationality and/or maivaise foi. Full pendulum swings between discussions and disputes are quite common in the participants own perception of their debates, for the existence of a tertium between these two extremes has been generally overlooked.

Obviously, if a debate’s type changes, the ways in which it can be concluded also change. Typically, discussions can be solved and disputes can be dissolved, whereas controversies can at most be resolved. However, the very possibility of type-shifts shows that any of these modes of conclusion may be only temporary. The possibility of such type-shifts can also serve as the basis for a strategy of conflict resolution (or escalation).

Thomas Kuhn’s account of the history of science in terms of ‘scientific revolutions’ as radical shifts of ‘paradigm’ from one period of ‘normal science’ another, which is incommensurable with the former, and Michel Foucault’s account of the history of ideas in terms of deep cleavages betweem radically different ‘épistémés’, can be described in terms of the proposed typology of debates. A period of ‘normal science’ is a period in which the predominant mode of debate is discussion, which relies on the shared ‘paradigm’. Similarly, an ‘épistémé’ consists in a shared background of conceptual tools and assumptions which allows for the formulation of well-defined ‘problems’ that can be discussed and solved within its framework. Scientific revolutions or épistémé cleavages, on the other hand, occur when the extamt framework itself is called into question due to its inability to cope with an increasing amount of problems or conceptual difficulties. In the situation of ‘crisis’ thus generated, the debates that arise between the existing framework and its competitors are described by Kuhn and Foucault as power struggles that clearly belong to the dispute type.

Both emphasize the fact that such revolutionary changes involve radical innovations, which couldn’t occur within the boundaries of the discussion model. But, by overlooking the controversy model, they are led to let the pendulum swing all the way from the discussion to the dispute model. As a result, their account is unable to account for whatever rationality there is in the growth of knowledge. This major shortcoming can be overcome by viewing conceptual revolutions as typically involving controversies rather than disputes. In fact, one of the main characteristics of controversies lies in the fact that their thematic expansion involves the questioning by each side of the most basic assumptions of the other, which, in turn, clears the ground for radical innovation. And yet, in a controversy, unlike in a dispute, rational argumentation prevails.

Furthermore, the core of some conceptual revolutions, as well as of most controversies, especially in philosophy, lies in the attempt to replace an established presumption by another. This claim will be illustrated through the analysis of the erklären / verstehen controversy.

My claim in this section is that the Explanation / Understanding (E/U) debate is, basically, a controversy. This claim is supported by a participant-observer of the E/U debate, G. H. von Wright throughout his well-known book on the topic. After describing the debate as an opposition between those who believe human actions must and can be explained causally and those who deny it, von Wright points out that pinpointing agreement or disagreement in the debate is not easy because the terms ‘cause’ and ‘action’ may be interpreted quite differently by the contenders. But he rejects the possibility that the issue could be settled by the simple procedure of meaning clarification leading to the adoption of a shared terminology, on the grounds that the elucidation of the meaning of the two terms links them to other, not less multi-valent, terms (such as ‘intention’, ‘motive’, ‘reason’) will be involved. His conclusion:

“The ‘causalist’ and the ‘actionist’, in other words, knit differently the conceptual web against whose background they see the world – and they therefore see the world differently (1971: viii).

The phenomenon von Wright highlights here is typical of controversies, where the participants (as well as the analysts) are forced to engage in endless interpretive work, whose need cabe obviated by arbitrary – albeit agreed upon – stipulation. Key terms in a controversy resist definitions in terms of necessary and sufficient conditions because they denote ‘cluster concepts’ and carry strong but different connotations for different speakers. Any attempt by a contender to promote one of the meaning components in the cluster to the status of a sufficient or necessary condition is itself a move in the controversy, which is likely to be detected and resisted by the opponent.

Other characteristic features of controversies, such as vertical and horizontal thematic shifts, multiple ramifications, the lack of a decision procedure, the types of arguments employed, etc., can also be discerned in the E/U debate.