Indeterminacy in Science

Principal Investigator:

Robert Michels

Funding Institution: FCT (2023.15136.PEX)
Date: 2024-26 (18 months)

Description

The natural sciences have produced astonishingly detailed and accurate theories about our universe. Most successful scientific theories are formulated using the precise language of mathematics, allowing them to remain free of the vagueness and indeterminacy which affects our ordinary language and thought. The substantial problems associated with indeterminacy in everyday contexts are well known. One such problem is posed by the sorites paradox, which has been discussed by philosophers since antiquity. The sorites arises due to the vagueness of ordinary concepts like “heap”, which lack precise boundaries for their application. The concepts used in scientific theories are largely free of this sort of indeterminacy, given that effectively usable technical terms are usually precisely defined. However, in recent years metaphysicians and philosophers of science have increasingly taken seriously the possibility that there are other forms of indeterminacy which may affect our scientific frameworks. A notable example from theoretical physics is that of Quantum Mechanics (QM)—one of the most empirically successful theories of the history of science—seems to imply that the fundamental constituents of matter in our universe are not completely determinate in their inherent properties.

 

This project systematically investigates alleged instances of metaphysical indeterminacy (MI), mind- and language-independent indeterminacy in the world, in science. It will both critically engage with arguments for the existence of indeterminacy in science, extend the scope of the investigation to, so far, under- or completely unexplored areas of the natural sciences, including relativistic physics, elaborate and assess recent controversial suggestions to the effect that the causal processes, or the laws of nature are indeterminate.

We will approach this investigation from two different perspectives:

 

– from the perspective of the philosophy of physics, and
– from the perspective of the metaphysics of science.

 

Considering the philosophy of physics, two focal points of the existing discussion are the indeterminacy of identity, in particular the question whether quantum particles are intrinsically indistinguishable, and the indeterminacy of observables, more specifically the question of what sort of MI is entailed by the failure of value-definiteness for quantum observables. Moreover, the main focus is on the standard formulation of QM, indeterminacy has also been studied in other interpretations of the quantum formalism, for instance relational quantum mechanics or decoherence-based Many Worlds Interpretations.

 

We aim to extend this literature, which is entirely based on non-relativistic physics, to the realm of Quantum Field Theory (QFT) and Quantum Gravity (QG). QFT is our most fundamental theory of matter and combines quantum mechanics with the special theory of relativity. QG represents our most advanced effort to unify QM with the general theory of relativity, providing a fundamental quantum description of spacetime itself. Thus, to really understand whether our world is inherently indeterminate at the fundamental level, one has to analyze the most advanced physical theories with the best tools available in analytic metaphysics.

 

In the second part of the project, we study the notion of indeterminacy from the perspective of the metaphysics of science focusing on two recent hypotheses. The first hypothesis is that fundamental laws of nature, according to Chen in particular the Past Hypothesis, can be indeterminate. Chen relies on a modal conception of laws as constraints and on a modal conception of indeterminacy in his argument. Both modal conceptions are controversial. We will hence investigate whether similar arguments can be constructed which rely on different conceptions of laws and on more orthodox non-modal conceptions of metaphysical indeterminacy. We will also explore an entirely new argument for the indeterminacy of the laws of nature: In the context of the Humean Best Systems Analysis (BSA), laws of nature are the result of a trade-off based on theoretic virtues. Systematic treatments of trade-offs in science usually allow for cases in which a number of results are equally (Pareto-)optimal. In the context of the BSA, such scenarios appear to imply that there is a plurality of “best” system, and not a single best system which uniquely determines the laws of nature. We will elaborate this argument and investigate its impact on the BSA.

Moreover, we will investigate recent arguments for indeterminate causation. These arguments rely on cases in which an omission to perform a certain action leads to a scenario in which one of a particular range of consequence is brought about by the omission, but it is metaphysically indeterminate which one. We will investigate whether this, or alternative proposed arguments in this very recent discussion, can be replicated in the context of the causal processes studies by the natural sciences.

 

Research Team

Claudio Calosi (Venice), Niels Linnemann (Geneva), Andrea Oldofredi (CFUL), Ricardo Santos (FLUL), Lisa Vogt (Geneva), David Yates (FLUL), and one postdoc (CFUL), to be hired.

Publications

Laws of nature as results of a trade-off — Rethinking the Humean trade-off conception by Niels Linnemann & Robert Michels, forthcoming in Philosophical Quarterly.

Humansplaining: is it a thing? Is it bad? by Robert Michels & Sanna Hirvonen in AI & Society.

Events

Two workshops in Lisbon, one in spring 2025, one in spring 2026. Indeterminacy in Science – First Workshop May 22-23 2025 Indeterminacy in Science - Second Workshop March 23-24 2026

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