The Fluidity of Warrants: Using the Toulmin Model to Analyse Practical Discourse

Modeling the invention of a new inference rule: The case of ‘Randomized Clinical Trial’ as an argument scheme for medical science

“…An argument warranted by a device may include interpretation of how the device was applied given the particular circumstances of application. A similar observation has been made by Tans [16] for the case of legal (judicial) reasoning; part of the fluidity of legal warrants is the work that goes into establishing whether some particular rule can be applied to a case. Device-based reasoning in science is at least as complex as judicial reasoning in this respect.…”

“…Since its invention (just a quarter-century ago), the Cochrane device has been strengthened through refinement of its procedures and through accumulation of material and institutional resources that make it technically superior to prior and competing reviewing methods. Individual reviews are thus being conducted under conditions of "fluidity" [16]: While all such reviews produce conclusions warranted by the Cochrane device, the device itself is still changing, generally becoming less vulnerable to criticism, but occasionally making trade-offs between scientific rigor and other goals (such as timeliness of response to clinical need). The Cochrane community implicitly recognizes that this fluidity means that conclusions drawn under one version of the device may be weaker than conclusions drawn under later versions of the device; in fact, a Cochrane Review may be "withdrawn" as it ages, not only because the evidence base may have changed but also because the procedures that were used may fail to satisfy a rising standard of proof associated with improvements in the device.…”