This paper explores the concept of infra-Bayesian physicalism and its application to interpreting quantum mechanics, particularly in the context of an agent-environment system. The author outlines their formal setup, including the definition of key terms such as 'agent', 'observation', and 'state'. They also delve into the differences between the traditional many-worlds interpretation and the infra-Bayesian physicalist setup. Finally, they provide an overview of the structure of the paper, dividing it into various sections.