John is a postdoctoral researcher at the Chair for Philosophy and Decision Theory at the Munich Center for Mathematical Philosophy at LMU Munich. Prior to this appointment, he was an FRHTP postdoctoral fellow at CQuIC (2022-2025) and a postdoctoral researcher at Tufts University (2020-2022).

John specializes in quantum foundations. His primary focus is QBism, an interpretation of quantum mechanics and ontological project that takes an agent's actions and experiences as the central concerns of the theory. His work has furthered the development of the QBist position as well as explored its technical consequences, particularly in the form of probabilistic reformulations and reconstructions of the structure of quantum theory. He is also interested in questions from the philosophy of mathematics and the philosophy of mind, especially as they intersect with the overarching theme of understanding what quantum theory can tell us about the nature of reality.