This event if part of the Sowerby Philosophy and Medicine colloqium at King's College London. All welcome!

http://philosophyandmedicine.org/

Marius Backmann, London School of Economics

Abstract:

Some necessitarians have claimed that they could justify induction by introducing necessary connections. By analysing the reasoning in randomised clinical trials (RCTs), I argue that this view does not accurately represent scientific practice.

The basic model of necessitarian solutions to the problem of induction is as follows: First we infer from the fact that all Fs have so far been Gs via an inference to the best explanation (IBE) that there is a necessary connection between F-ness and G-ness. We then deductively infer from this necessary connection that all Fs are Gs.

Nancy Cartwright and Eileen Munro offer an idealised reconstruction of randomized clinical trials broadly along these lines. First, we infer from evidence that a treatment has a ‘stable capacity’, i.e. a modal dispositional property, to produce an outcome. Second, we deductively infer the efficacy ofthe treatment outside the test environment from the existence of this stable capacity. Cartwright and Munro argue that RCTs alone are no basis to support these sorts of inferences, and hence do not deserve the status of a gold standard for medical research.

Against this, I argue we should not try to give a deductive reconstruction of RCTs. We ampliatively infer the causal relevance of the treatment in the sample from the fact that the desired outcome is more prevalent in the test group than in the control group. The further inference that the treatment will be causally relevant in the population will also always be ampliative, because we cannot possibly have the necessary information to make it deductive. Moreover, the necessitarian analysis of inductive practice is inapplicable where there are no modal properties that could be inferred to, as is, e.g., the case in meta-studies.