Cosmology: The Impossible Integration?

My dissertation introduces a new account of how empirical methods and lines of evidence can come to bear on cosmological model-building. Through a careful study of the recent history of cosmology and dark matter research, I explicate a new type of justification for experiments, a `method-driven logic'. This structure of justification underlies terrestrial experiments researching dark matter and dark energy, but it is more generally prevalent in cases of an underdescribed target. Using a method-driven logic comes with a cost, however. Specifically, interpreting the empirical results of experiments justified through a method-driven logic is non-trivial: negative results warrant secure constraints on the space of possibilities for the target, whereas significant positive results remain ambivalent. While this ambivalence can be resolved through the amalgamation of multiple lines of evidence, this solution is sometimes faced with conflicts between those lines of evidence. I propose that, under specific circumstances, restricting the relevant empirical evidence can be warranted. Finally, I discuss the use of cosmological evidence as a constraint in other subfields of physics. This brings me full-circle on the integration of disciplines in cosmology|an integration driven by experimental practice

Jump Ship, Shift Gears, or Just Keep on Chugging: Assessing the Responses to Tensions between Theory and Evidence in Contemporary Cosmology

When is it reasonable to abandon a scientific research program? When would it be premature? We take up these questions in the context of a contemporary debate at the border between astrophysics and cosmology, the so-called “small-scale challenges” to the concordance model of cosmology (ΛCDM) and its cold dark matter paradigm. These challenges consist in discrepancies between the outputs of leading cosmological simulations and observational surveys, and have garnered titles such as the Missing Satellites, Too Big To Fail, and Cusp/Core problems. We argue that these challenges do not currently support a wholesale abandonment or even modification of cold darkmatter. Indeed, the nature of the challenges suggests prioritizing the incorporation of known physics into cosmological simulations

Better appreciating the scale of it (Lemaître and de Sitter at the BAAS Centenary)

In September 1931, a panel discussion was convened at Central Hall Westminster on the subject of the 'Evolution of the Universe', at the centenary meeting of the British Association for the Advancement of Science. Center stage was what to do about the evolving universe being younger than the stars, evidently a paradox in the relativistic study of the evolving universe, at the time. Here, we discuss two diametrically opposed reactions to the paradox, which were each broadcast at the meeting by Lemaître and de Sitter, respectively. As we argue, that both could be projected to the public as viable reflects an unsettled question at the foundations of the then-nascent discipline: what is the role for considerations of scale in relativistic cosmology

MOND and Meta-Empirical Theory Assessment

While ΛCDM has emerged as the standard model of cosmology, a small group of physicists defend Modified Newtonian Dynamics (MOND) as an alternative view on cosmology. Exponents of MOND have employed a broad, at times explicitly philosophical, conceptual perspective in arguing their case. This paper offers reasons why that MONDian defense has been ineffective. First, we argue that the defense is ineffective according to Popperian or Lakatosian views--ostensibly the preferred philosophical views on theory assessment of proponents of MOND. Second, we argue that the defense of MOND can instead best be reconstructed as an instance of meta-empirical theory assessment. The formal employment of meta-empirical assessment by MONDians is unconvincing, however, because it lacks a sufficient epistemic foundation. Specifically, the MONDian No Alternatives Argument relies on falsifiability or explanation conditions that lack epistemic relevance, while the argument from Unexpected Explanatory Success fails since there is a known alternative to MOND. In the last part of the paper, we draw some lessons for applications of meta-empirical assessment more generally

MOND and Meta-Empirical Theory Assessment

While ΛCDM has emerged as the standard model of cosmology, a small group of physicists defend Modified Newtonian Dynamics (MOND) as an alternative view on cosmology. Exponents of MOND have employed a broad, at times explicitly philosophical, conceptual perspective in arguing their case. This paper offers reasons why that MONDian defense has been ineffective. First, we argue that the defense is ineffective according to Popperian or Lakatosian views--ostensibly the preferred philosophical views on theory assessment of proponents of MOND. Second, we argue that the defense of MOND can instead best be reconstructed as an instance of meta-empirical theory assessment. The formal employment of meta-empirical assessment by MONDians is unconvincing, however, because it lacks a sufficient epistemic foundation. Specifically, the MONDian No Alternatives Argument relies on falsifiability or explanation conditions that lack epistemic relevance, while the argument from Unexpected Explanatory Success fails since there is a known alternative to MOND. In the last part of the paper, we draw some lessons for applications of meta-empirical assessment more generally

MOND and meta-empirical theory assessment

While ΛCDM has emerged as the standard model of cosmology, a small group of physicists defends modified newtonian dynamics (MOND) as an alternative view on cosmology. Exponents of MOND have employed a broad, at times explicitly philosophical, conceptual perspective in arguing their case. This paper offers reasons why that MONDian defense has been ineffective. First, we argue that the defense is ineffective according to Popperian or Lakatosian views–ostensibly the preferred philosophical views on theory assessment of proponents of MOND. Second, we argue that the defense of MOND can instead best be reconstructed as an instance of meta-empirical theory assessment. The formal employment of meta-empirical assessment by MONDians is unconvincing, however, because it lacks a sufficient epistemic foundation. Specifically, the MONDian No Alternatives Argument relies on falsifiability or explanation conditions that lack epistemic relevance, while the argument from Unexpected Explanatory Success fails since there is a known alternative to MOND. In the last part of the paper, we draw some lessons for applications of meta-empirical assessment more generally

Cosmology and empire

What is the link between the discovery of the relativistic expanding Universe and British imperialism? A public panel debate in the early days of relativistic cosmology shows how fundamental scientific research, whether there are obvious political stakeholders (like biosecurity and climate) or not, runs real-time risks of being repurposed for political ends.Discovering dark matter: Extending Philosophy of Experiment to Dark Matte

Better appreciating the scale of it : Lemaître and de Sitter at the BAAS Centenary

In September 1931, a panel discussion was convened at Central Hall Westminster on the subject of the 'Evolution of the Universe', at the centenary meeting of the British Association for the Advancement of Science. Center stage was what to do about the evolving universe being younger than the stars, evidently a paradox in the relativistic study of the evolving universe, at the time. Here, we discuss two diametrically opposed reactions to the paradox, which were each broadcast at the meeting by Lemaître and de Sitter, respectively. As we argue, that both could be projected to the public as viable reflects an unsettled question at the foundations of the then-nascent discipline: what is the role for considerations of scale in relativistic cosmology