Inflation
Another critical look at inflationary cosmology
I present an overview of the criticism of the theory of cosmological inflation of the past 25 years. I argue that the three main problems motivating the inflationary explanation are the flatness problem, the uniformity problem, and the structure formation problem. The flatness problem has been resolved. In analysing the other two problems, an alternative explanation emerges. This explanation relies on law-like assumptions about the initial conditions of the universe. I claim that this is a proper explanation. This places the inflationary explanation on par with an alternative explanation. I argue that different extra-empirical considerations lead cosmologists to prefer one above the other. The way forward lies in the middle: an amalgam of the two explanations promises to be the most fruitful.
Twin Master thesis in Mathematical Sciences and History & Philosophy of Science by Alex Fleuren (2024)
Supervised by: Dr. Niels Martens (HPS), Prof. Dr. Gil Cavalcanti (Mathematical Sciences), Dr. Antonio Ferreiro (HPS & Physics)
Inflation vs. Initial Conditions: Rethinking Explanations for the Early Universe
I argue that the three main problems motivating an inflationary explanation today are the flatness problem, the uniformity problem, and the structure-formation problem. The flatness problem has been resolved. In analysing the other two problems, an alternative explanation emerges. This explanation relies on law-like assumptions about the initial conditions of the universe. I claim that this is a proper explanation, with the additional advantage that it can easily resolve the entropy problem. This places the inflationary explanation on par with an alternative explanation. I argue that different extra-empirical considerations lead cosmologists to prefer one over the other. Nevertheless, some promising solutions to the uniformity, entropy, and structure-formation problems incorporate elements from both styles of explanation. Rather than restricting research efforts to one style of explanation, there may be a high payoff in exploring these hybrid solutions.
Alex Fleuren (under review)
A Reassessment of the Meta-Empirical Evaluation of Cosmological Inflation
In a recent paper, William Wolf applies the framework of meta-empirical theory confirmation of Richard Dawid to the theory of cosmological inflation. Wolf challenges the applicability of the meta-inductive argument in the inflationary context. This is supported by the argument that the big bang theory, without inflation, is empirically adequate, questioning the possibility of a meta-inductive inference for the cosmology research programme. I argue that Wolf and Dawid diverge in their interpretations of the meta-inductive argument, threatening the argumentative structure of the framework of metaempirical theory confirmation. Next, I claim that the meta-inductive argument can still be applied in the case of inflation. Finally, I dispute Wolf’s arguments concerning the empirical adequacy of the big bang theory.
Alex Fleuren (under review)
Deflating the spacetime-matter distinction
In this paper we analyse scalar-tensor theories—specific instances of which include mainstream inflation and dark energy models—in light of the spacetime-matter dichotomy. We argue that it is difficult to categorise the scalar fields as either a pure aspect of the spacetime structure or a pure form of matter, for instance by focusing on the Jordan vs Einstein frames of these theories. We introduce and partially evaluate the various interpretational options available, such as functionalism, moving to a reduced theory, and breaking down the spacetime-matter dichotomy (e.g. conventionalism).
Antonio Ferreiro, Alex Fleuren & Niels Martens (in progress)
