Scientism is a philosophy which purports to define what the world ‘really is’. It adopts what the philosopher Thomas Nagel called ‘an epistemological criterion of reality’, defining what is real as that which can be discovered by certain quite specific methods of investigation. As a consequence all features of experience not revealed by those methods are deemed ‘subjective’ in a way that suggests they are either not real, or lie beyond the scope of meaningful rational inquiry. This devalues capacities that (...) (we argue) are in fact essential components of good reasoning and virtuous practice. Ultimately, the implications of scientism for statements of value undermine value-judgements essential for science itself to have a sound basis. Scientism has implications, therefore, for ontology, epistemology and also for which claims we can assert as objective truths about the world. Adopting scientism as a world view will have consequences for reasoning and decision-making in clinical and other contexts. We analyse the implications of this approach and conclude that we need to reject scientism if we are to avoid stifling virtuous practice and to develop richer conceptions of human reasoning. (shrink)

In this essay, we defend the design of the Salk polio vaccine trial and try to put some limits on the role schemata should play in designing clinical research studies. Our presentation is structured as a response to de Freitas and Pietrobon who identified the CONSORT statement as a schema that would have, had it existed at the time, ruled out the design of the Salk polio vaccine trial of 1954 in favor of a completely randomized controlled clinical trial. We (...) argue that large-scale public health interventions often require evidence beyond simple efficacy, the limit of what an RCT can provide, and that the design actually adopted for the Salk trial represented a reasonable—albeit imperfect—compromise. This is of more than historical interest in that many contemporary studies are of the scale and scope to require a more pragmatic, rather than explanatory, approach to study design. (shrink)

Hierarchies of evidence are an important and influential tool for appraising evidence in medicine. In recent years, hierarchies have been formally adopted by organizations including the Cochrane Collaboration [1], NICE [2,3], the WHO [4], the US Preventive Services Task Force [5], and the Australian NHMRC [6,7]. The development of such hierarchies has been regarded as a central part of Evidence-Based Medicine, a movement within healthcare which prioritises the use of epidemiological evidence such as that provided by Randomised Controlled Trials. Philosophical (...) work on the methodology of medicine has so far mostly focused on claims about the superiority of RCTs, and hence has largely neglected the questions of what hierarchies are, what assumptions they require, and how they affect clinical practice. This thesis shows that there is great variation in the hierarchies defended and in the interpretations they are, and can be, given. The interpretative assumptions made in using hierarchies are crucial to the content and defensibility of the underlying philosophical commitments concerning evidence and medical practice. Once this variation is been identified, it becomes clear that the little philosophical work that has been done so far affects only some hierarchies, under some interpretations. Modest interpretations offered by La Caze [11], conditional hierarchies like GRADE [12-14], and heuristic approaches such as that defended by Howick et al. [15,16] all survive previous philosophical criticism. This thesis extends previous criticisms by arguing that modest interpretations are so weak as to be unhelpful for clinical practice; that GRADE and similar conditional models omit clinically relevant information, such as information about variation in treatments’ effects and the causes of different responses to therapy; and that heuristic approaches lack the necessary empirical support. The conclusion is that hierarchies in general embed untenable philosophical assumptions: principally that information about average treatment effects backed by high-quality evidence can justify strong recommendations, and that the impact of evidence from individual studies can and should be appraised in isolation. Hierarchies are a poor basis for the application of evidence in clinical practice. The Evidence-Based Medicine movement should move beyond them and explore alternative tools for appraising the overall evidence for therapeutic claims. (shrink)