Wellman identified three types of conductive arguments, the third of which contains both pro and counter-considerations in the same piece of reasoning. This paper provides a pragma-dialectical analysis of this type of argumentation, with special focus on argumentation reconstruction. It argues that the account of pro/con argumentation in the framework of argument-as-product has problems solvable by a pragma-dialectical approach. The paper asserts that pro/con argumentation should be analyzed as a dialectical strategy of a protagonist, where acknowledgement of counter-considerations shows that (...) the antagonist’s reasons have been taken into consideration, although the pro-considerations override them. Thus, the pro-considerations of pro/con argumentation should be interpreted as the protagonist’s overriding defeaters of the antagonist’s counter-arguments, the protagonist incorporating the latter as counter-considerations. The paper further argues that the pragma-dialectical framework needs an additional conceptual tool to properly reconstruct complex forms of pro/con argumentation. Finally, the pragma-dialectical approach to reconstruct pro/con argumentation has several advantages, especially to a more logical-structural approach to complex pro/con argumentation. (shrink)

Corroborative evidence has a dual function in argument. Primarily, it functions to provide direct evidence supporting the main conclusion. But it also has a secondary, bolstering function which increases the probative value of some other piece of evidence in the argument. This paper argues that the bolstering effect of corroborative evidence is legitimate, and can be explained as counter–rebuttal achieved through inference to the best explanation. A model (argument diagram) of corroborative evidence, representing its structure and operation as a schematic (...) pattern of defeasible argument is also supplied. In addition to explaining the operation and theoretical foundation of corroborative evidence, the model facilitates the correct analysis and guides the evaluation (assessment and critique) of corroborative evidence as it occurs in argument. (shrink)

Corroborative evidence can have a dual function in argument whereby not only does it have a primary function of providing direct evidence supporting the main conclusion, but it also has a secondary, bolstering function which increases the probative value of some other piece of evidence in the argument. It has been argued (Redmayne, 2000) that this double function gives rise to the fallacy of double counting whereby the probative weight of evidence is overvalued by counting it twice. Walton has proposed (...) several models of corroborative evidence, each of which seems to accept the fallaciousness of double counting thereby seeming to deny the dual function of corroborative evidence. Against this view, I argue that the bolstering effect is legitimate, and can be explained by recourse to inference to the best explanation. (shrink)

An essential step to evaluating arguments is moving from the weight of individual premises to the weight of the conclusion. In order to perform this step, one must understand the relationship between the premises in the argument. In the past, analyzing premise relations in informal logic has been limited primarily to the linked-convergent distinction. This distinction has failed to resolve some of the basic problems in finding a definition because it has underestimated the degree to which premises interact with each (...) other in some complicated way. Embracing concepts from holistic epistemology, I argue that evaluating a premise involves considering a wide set of presuppositions and implications that that premise, if accepted, carries. I call this wide set the premise/world. The relationship between premises is then essentially just the relationship between these two premise/worlds. (shrink)