Popper Seminar by Karim Thébault (University of Bristol) and Samir Okasha (University of Bristol)

Title: Confirmation and Artefact Asymmetry: A Bayesian Analysis

Abstract: Are there ever situations in which scientists can gain evidence for the existence of a phenomenon based upon an observation via experimental apparatus that they do not know is reliable? A standard assumption in the epistemology of experiment is that a necessary condition for credible presentation of empirical results is properly calibrated and operating instruments, the functioning of which is adequately understood for the purpose at hand (Boyd 2021). Such a stringent necessary condition appears, however, in tension with examples from early phases of science, most iconically Galileo's telescopic observations, when scientists have very little knowledge regarding either the reliability of their instruments or the existence of the phenomenon. Taking inspiration from related qualitative (Franklin 1984) and quantitative (Bovens and Hartmann, 2002) analysis, we isolate probabilistic conditions for Artefact Asymmetry Situations wherein Bayesian confirmation of hypotheses regarding the phenomenon obtains despite complete subjective uncertainty regarding the reliability of the apparatus and the existence of the phenomenon. We further derive the conditions under which confirmation of the reliability of the apparatus also obtains and examine the implications of including statistical error effects according to the approach of Osimani and Landes (2023). Our formal analysis of Artefact Asymmetry Situations and their contrast cases will be illustrated with reference to a selection of examples from the history of the physical and life sciences and we will conclude by sketching a potentially pivotal 'bootstrapping' role for such situations in the development of scientific knowledge.

Bovens, L. and S. Hartmann (2002). Bayesian networks and the problem of unreliable instruments. Philosophy of Science 69 (1), 29–72.

Boyd, N. M. (2021). Epistemology of Experimental Physics. Cambridge University Press.

Franklin, A. (1984). The epistemology of experiment. The British Journal for the Philosophy of Science 35 (4), 381–390.

Osimani, B. and J. Landes (2023). Varieties of error and varieties of evidence in scientific inference. The British Journal for the Philosophy of Science 74 (1), 117–170

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