Following earlier works by Michel Bitbol and Laura de la Tremblaye, which examine QBism from the perspective of phenomenology, this chapter explores points of contact between QBism and Maurice Merleau-Ponty's essay The intertwining—the chiasm .
This is the first volume that focuses specifically on phenomenological approaches to quantum mechanics. It is also the first volume focusing on the philosophical implications of QBism. This coincidence is not accidental. Phenomenology's rich potential for our understanding of quantum mechanics has long been overlooked by analytic philosophers and phenomenologists alike. The experience-first approach of phenomenology, its descriptive methodology, and Husserl's critique of mathematization do not sit well with “mainstream” analytic philosophy of physics. But as this volume will demonstrate, it sits nicely with the basic tenets of QBism. Conversely, QBism constitutes the most consistent and best-developed interpretation of quantum mechanics that fully embraces the Bohrian idea that a proper understanding of science must be based on the concept of experience. However, since its inception in the early 2000s, QBism has struggled to connect with the philosophical community. Not only are the underlying intuitions shaping and dominating contemporary philosophy of quantum mechanics—namely, that a scientific theory must be purged of all subjective and operational notions such as “experience” or “measurement” and that, consequently, a successful approach to quantum mechanics must be formulated as a “quantum theory without observers”—at odds with QBism. It seems that sometimes the incommensurability already starts at the level of the basic conceptual framework which, in the case of mainstream analytic philosophy, is not very well suited to express some of QBism's main tenets. Considering this situation, the main hypothesis of this volume is that phenomenology and QBism are natural bedfellows, and that both can profit from mutual exchange. In order to make this exchange as profitable as possible, the aim of this introductory chapter is to identify, clarify, and motivate some of the cornerstones of phenomenological approaches to quantum mechanics, to shed light on the main ideas and virtues of QBism, and to discuss points of contact and points of possible conflict between these two projects.
The history of QBism is interestingly complex, leading to misunderstandings and misapprehensions as to its core features. Fuchs has usefully situated those features within the framework constituted by forms of ‘participatory realism’ according to which measurement devices should be considered to be extensions of agents. Examining that claim, Pienaar has articulated the conditions that such devices must meet to be so considered. However, there has yet been little similar consideration of the conditions that agents must meet in this regard. Here I shall examine the proposal that adopting a phenomenological stance may fill the gap in the QBists’ picture and I shall present an alternative ‘correlational’ account.