CEPPA Talk (in-person & online) – Adrian Walsh (University of New England)

Title: Internal Validity, External Validity and the Evaluation of Thought Experiments in Applied Ethics and Political Philosophy

Abstract: Thought experiments clearly play a central role in much contemporary ethical theorising. In the recent literature on thought experiments, some commentators (e.g. Wilson 2016; Dowding 2019) have criticised the lack of attention paid by moral philosophers to two ideas which are key notions in science. These are internal and external validity. Wilson argues that if thought experiments are indeed a kind of experiment, then philosophers should begin any plausible search for rigour in the scientific literature on experimental research design. When designing a thought experiment, Wilson suggests we consider the extent to which ethical judgements that are correct or endorsed in the world of the experiment generalise to the world beyond the experiment. This is an important question to consider. However, I suggest that Wilson’s approach (i) overstates the connection between real-world scientific experiments and thought experiments (ii) focuses too readily on the formal structure of thought experiments at the expense of the argumentative context. With respect to the former claim, I suggest that this points towards a more general thesis that it is a mistake to treat the reasoning involved in the use of thought experiments as a subset of scientific reasoning. I shall also consider, towards the end of the talk, a more moderate (and plausible) view of the positive role that the concepts of internal and external validity might play in evaluating and assessing the legitimacy of thought experiments.

Location: Edgecliffe G03