Initial reflections on the nature of scientific evidence

Please note that this post is from 2011. Evaluate with care and in light of later events.

For the last week I’ve been a part of the Vienna Institute Summer University (VISU) at the University of Vienna, at a two-week conference on “The Nature of Scientific Evidence.” The program brings together graduate students from a variety of disciplines from around the world to discuss science-related topics. Key lecturers this year include Hasok Chang (Philosophy of Science/Cambridge), David Lagnado (Cognitive Psychology/UCL) and Tal Golan (History of Science/UCSD). Interestingly for my interest in law and science, both Lagnado and Golan have focused on the legal sphere as a powerful “theater” for investigating the (ab)use of scientific evidence.

We can characterize the approaches quickly as follows: Chang discusses the theoretical underpinnings of science, including the logical reasoning process; Golan looks at the historical growth of science in the public imagination and the development of scientific experts; and Lagnado investigates the use of Bayesian networking to understand a cognitive approach to weighing evidence, both normatively and descriptively.

Given that I am an historian of law and technology, and a lawyer, what kinds of takeaways have I gotten so far?

First, that Bayesian networking could be highly beneficial to lawyers, especially in criminal defense. The approach has problems, but is a powerful way to avoid common pitfalls in evidential reasoning.

Second, that scientific evidence is not radically different from other evidence, and that the fallacies that scientists encounter internally are not radically different than when they present externally (this is more controversial, perhaps).

Third, that context is key to evidence, to the acceptance of evidence, and to the use of evidence. One cannot consider all variables, nor all potential outcomes or possibilities, so all decisions made from evidence are bound up in both one’s own context and from the context the evidence came from. (This doesn’t mean that all decisions are necessarily totally subjective and arbitrary, however).

Fourth, that many disciplines can come together and discuss common questions in a useful and powerful way, but that it isn’t always easy to speak a mutually intelligible common language (and I’m not talking about English vs. German).

I will have more to say later.