Is it possible to know cosmological fine-tuning?

TL;DR

This paper examines whether cosmological fine-tuning can be known and argues that, under certain conditions, it is possible to formally assess fine-tuning using a mathematical framework of knowledge and probability.

Contribution

It introduces a formal epistemological approach to evaluate the knowability of cosmological fine-tuning, clarifying when such assessments are valid.

Findings

Most examples of fine-tuning cannot be formally assessed as such.

Fine-tuning can be known if the parameter is a nonnegative random variable with a small life-permitting interval relative to its observed value.

Abstract

Fine-tuning studies whether some physical parameters, or relevant ratios between them, are located within so-called life-permitting intervals of small probability outside of which carbon-based life would not be possible. Recent developments have found estimates of these probabilities that circumvent previous concerns of measurability and selection bias. However, the question remains if fine-tuning can indeed be known. Using a mathematization of the epistemological concepts of learning and knowledge acquisition, we argue that most examples that have been touted as fine-tuned cannot be formally assessed as such. Nevertheless, fine-tuning can be known when the physical parameter is seen as a random variable and it is supported in the nonnegative real line, provided the size of the life-permitting interval is small in relation to the observed value of the parameter.