Analyzing the Multiverse with Bayesianism

Abstract

Multiverse is a popular concept embraced by many scholars, including physicists who support the many-worlds interpretation of quantum mechanics. However, the necessity of adding many extra entities to the traditional single universe is debatable. Bayesianism, which contends to utilize degrees of belief to measure our credence, is a suitable tool to be introduced in this debate. This paper discusses the reason for believing in the multiverse and utilizes Bayesianism, claiming that we should believe in the multiverse due to the fine-tuned constants. The fine-tuned universe and Bayes’ Rule are introduced, then the inverse gambler’s fallacy is explained to object to the reasoning of the multiverse. Subsequently, however, the paper raises examples and Bayesian calculations to argue that the multiverse is good reasoning. Finally, the paper concludes that the multiverse is good reasoning by using ‘selection effects’ to distinguish it from the inverse gambler’s fallacy.