The development of nineteenth-century geodetic measurement challenges the dominant coherentist account of measurement success. Coherentists argue that measurements of a quantity are epistemically successful if their numerical outcomes converge across varying contextual constraints. Aiming at numerical convergence, in turn, offers an operational aim for scientists to solve problems of coordination. Geodesists faced such a problem of coordination between two indicators of the earth’s ellipticity, which were both based on imperfect ellipsoid models. While not achieving numerical convergence, their measurements produced novel (...) data that grounded valuable theoretical hypotheses. Consequently, they ought to be regarded as epistemically successful. This insight warrants a dynamic revision of coherentism, allowing to judge the success of a metric based on both its coherence and fruitfulness. On that view, scientific measurement aims to coordinate theoretical definitions and produce novel data and theoretical insights. (shrink)

In 2012, the Geological Time Scale, which sets the temporal framework for studying the timing and tempo of all major geological, biological, and climatic events in Earth’s history, had one-quarter of its boundaries moved in a widespread revision of radiometric dates. The philosophy of metrology helps us understand this episode, and it, in turn, elucidates the notions of calibration, coherence, and consilience. I argue that coherence testing is a distinct activity preceding calibration and consilience, and I highlight the value of (...) discordant evidence and trade-offs scientists face in calibration. The iterative nature of calibration, moreover, raises the problem of legacy data. (shrink)

The philosophical significance attached to the construction of systems of units has traditionally been confined to the notion of convention, while their adoption was considered to be the exclusive province of the history and sociology of science. Against this tradition, a close articulation between history, philosophy, and sociology of science is needed in order to analyse the recent reform of the International system of units. In the new SI, units are redefined on the basis of certain fundamental constants of nature, (...) established by physical theories, whose values are fixed without uncertainty. The purpose of this article is to show that the redefinition of SI units, far from being a convention, involves a holistic reconstruction of our concepts of quantities from accepted theoretical laws. Fixing the values of the defining constants stabilizes these laws within the framework of physics through a twofold adjustment procedure that ensures both a semantic coordination between theory and world and an intersubjective coordination between human agents required by social activities. This double adjustment implies a treatment of uncertainties that results in closely entwining the pursuit of truth as correspondence and truth as coherence which turn out to be complementary, thus highlighting the anthropological underpinnings of scientific realism. (shrink)

This article develops a historico-critical analysis of uncertainty and accuracy in measurement through a case-study of the adjustment of the fundamental physical constants, in order to investigate the sceptical “problem of unknowability” undermining realist accounts of measurement. Every scientific result must include a “measurement uncertainty”, but uncertainty cannot be be eval- uated against the unknown, and therefore cannot be taken as an assessment of “accuracy”, defined in the metrological vocabulary as the closeness to the truth. The way scientists use and (...) interpret uncertainty in the adjustment activity illustrates how they try to overcome this predicament. I iden- tify two operative roles of measurement uncertainty, in the comparison and in the combination of measurement results. This duality implies a tension between selection and combination when aggregating results, leading to a crucial question: should the evaluation of uncertainties favour safety over precision? I present contrasting answers and identify a specific account of physicists who implicitly try to conciliate realism with the problem of unknowability. I argue that this invites us to reconsider accuracy from a dynamical standpoint, as the gradual achievement of scientific progress through error correction. Finally, I present two interpretations of measurement uncertainty, objective and epistemic, which I criticize and suggest improvements to. (shrink)