Do anthropic arguments really work?

TL;DR

This paper critically examines the anthropic explanation for the small observed cosmological constant, showing that the relationship between star formation efficiency and observer likelihood is complex and not directly proportional.

Contribution

It introduces a new analytic model of cosmic star formation that challenges the straightforward link between star formation efficiency and the likelihood of observers.

Findings

Maximum star formation efficiency occurs at the observed $\Lambda$

Observer probability peaks at 400-500 times the observed $\Lambda$

Highlights complexities in applying anthropic reasoning to cosmological constants

Abstract

The anthropic explanation for the peculiarly small observed value of the cosmological constant $\Lambda_{\rm obs}$ argues that this value promotes the formation of stars, planets, and ultimately of observers such as ourselves. I show that a recent analytic model of cosmic star formation predicts that although $\Lambda_{\rm obs}$ maximises the overall efficiency of star formation in the universe, the probability of generating observers peaks at $\sim400-500 \, \Lambda_{\rm obs}$. These preliminary results suggest that an immediate connection between star formation efficiency and observers' generation is not straightforward, and highlight the subtleties involved with the application of anthropic reasoning.