CONVERGENT argumentation
Convergence is a basic mode of organization of complex discourse to support a conclusion, S. Convergent, Linked, Serial.
Two or more arguments are convergent when they independently support the same conclusion. The arguments are said to be co-oriented, and the argumentation is said to be convergent or multiple.
“Two reasons are better than one”: In a convergent argumentation, a claim is defended on the basis of several arguments that, taken separately, may be relatively weak, but, taken together, combine to make a stronger case: “My computer is getting old, there are discounts on the price of my favorite brand, I’ve just got a bonus, I’m going to buy one! ”.
The above diagram shows each argument is represented as a whole. The following diagram spells out the transition laws according to Toulmin’s proposal, S. Layout; compare with linked argumentation:
As well as pro-arguments, counter-arguments can converge to refute a claim. S. Script.
This open structure defines the argumentative network, in contrast to the demonstrative chain. In the demonstrative chain, each step is necessary and sufficient; if one step is invalid, the whole construction collapses. In the case of the argumentative net, if one link in the mesh is broken, the net can still be used to catch fish, at least the biggest ones.
In a convergent argumentation, the organization of the sequence of arguments is relevant. If the arguments are of a very different strengths, a ridiculous or a weak argument next to a strong one risks damaging the whole argumentation, especially if thatargument ends the enumeration:
He’s a great hunter, he killed two deer, three wild boars and a rabbit.
In classical rhetoric, the theory of the general organization of discourse (Lat. dispositio) discussed the supposedly different persuasive effects of the various possible textual arrangements of converging arguments of different strength, S. Rhetoric.
Convergent arguments can be merely listed (paratactic disposition):
Arg, Arg and Arg, so Concl
They can be connected by any listing or additive connective:
first, Arg1; second, Arg2; third, Arg3; so Concl.
Additionally, also, in addition, let alone, moreover, not only,
besides
Connectives such as besides, not only, in addition, let alone, not to mention… not only add argument(s) upon argument(s), they present them as if each one were actually sufficient for the conclusion, and only added just “for good measure” (Ducrot & al. 1980, pp. 193-232):
No, Peter will not come on Sunday, he has work, as usual, besides his car broke down.
The additive approach holds that each argument contributes a piece of truth, and that these pieces can be arithmetically added together, to form a large, conclusive discourse. Speech activity theory holds that, by default, an argument is presented as sufficient, and that the addition of other arguments actually follows the logic of commercial presentation to consumers (the audience), i.e. the speaker offers the audience a series of arguments he considers equally satisfying and self-sufficient .
Case-by-case argument — To refute the conclusion of a convergent argument, each of the arguments supporting that conclusion must be refuted. Thus, a convergent argument is countered by a case-by-case rebuttal, limited to the cases presented by the proponent.