Jürgen Landes visits George Masterton

Jürgen Landes, Postdoctoral Researcher at the Munich Center for Mathematical Philosophy visited George Masterton, Postdoctoral Fellow in the Department of Philosophy at Lund University from May to July, 2017.


One key challenge in medical inference are the enormous sums at stake and the hence inherent vested interests. The reliability of all items of available evidence therefore needs to be carefully assessed. Intuitively, the greater the variety of sources and kinds of evidence which point in the same direction, the higher the assessed reliability and thus stronger the evidence confirms a hypothesis, ceteris paribus. This intuitive thought is known as Variety of Evidence Thesis.

Previous work, Bovens and Hartmann [2003] and Claveau [2013], on this thesis reports surprising failures in which the less diverse body of evidence for a hypothesis confirms the hypothesis more strongly than the more diverse body of evidence. Landes and Osimani [2017] have developed a framework for the formal evaluation of the Variety of Evidence Thesis under more realistic modelling assumptions regarding the reliability of scientific instruments which are closer to statistical practise. The upshot is that the Variety of Evidence Thesis fails mostly for borderline or counter-intuitive cases and holds otherwise. However, when reliability is modelled exogenously, then the Variety of Evidence Thesis does hold and it can be given a formal Bayesian justification, see Landes [2017].

These papers are embedded in an overarching framework aiming to provide a formal analysis of statistical inference, see Landes et al. [2017]. The aim here is twofold: on a more theoretical level, formal epistemology should provide a sort of lingua franca, where different conceptualisations of error and different statistical techniques can be discussed and investigated; on a more practical level, we aim to use formal epistemology as a framework for the incorporation of various evidential dimensions in the overall assessment of investigated hypotheses.

Within this context I visited George Masterton (based at Lund university) who is an expert in judgement aggregation and the philosophy of science. He is involved in the application of Laputa which is a research tool and a sandbox environment for simulating the attainment of knowledge in social networks, see Masterton and Olsson [2013], Masterton [2014]. Having successfully cooperated (Landes and Masterton [2017]), I visited George Masterton in Lund to apply Laputa to the problem of modelling reliability of evidence in medical inference and how different concepts of the notion of reliability influence rational (Bayesian) beliefs in a social world. Work on a jointly-authored manuscript has begun. Barbara Osimani has kindly agreed to participate in the joint effort. We are looking forward to a joyful and labor-intensive period of readings, discussions and writing. We would all like to thank Richard Pettigrew, the Leverhulme Trust and the European Research Council for making this cooperation a reality.

Luc Bovens and Stephan Hartmann. Bayesian Epistemology. Oxford University Press, 2003.

Francois Claveau. The Independence Condition in the Variety-of-Evidence Thesis. Philosophy of Science, 80(1):94{118, 2013. URL

Jürgen Landes. Variety of Evidence. Erkenntnis, 2017. 41 pages, submitted.

Jürgen Landes and George Masterton. Invariant Equivocation. Erkenntnis, 82:141{167, 2017. URL

Jürgen Landes and Barbara Osimani. Exact replication or varied evidence? The Varied of Evidence Thesis and its methodological implication in medical research. British Journal for the Philosophy of Science, 2017. 59 pages, submitted.

Jürgen Landes, Barbara Osimani, and Roland Poellinger. Epistemology of Causal Inference in Pharmacology. European Journal for Philosophy of Science, 2017. URL pages.

George Masterton. Topological variability of collectives and its import for social epistemology. Synthese, 191(11):2433{2443, 2014. URL

George Masterton and Erik J. Olsson. Argumentation and belief updating in social networks: a Bayesian approach. In E Ferme, D. Gabbay, and G. Simari, editors, Trends in belief revision and argumentation dynamics. College Publications, 2013.