How QBism grounds quantum theory in the reality of lived experience

Quantum theory has a reputation for being notoriously abstract, counter-intuitive and even paradoxical. All attempts to explain its predictions in terms of material bodies moving in space and time invariably lead to bizarre consequences: some proposals imply the existence of parallel worlds; others invoke instantaneous effects violating the locality principle; still others call for a radical revision of our understanding of material cause and effect. Among today’s most prominent interpretations, QBism — whose name is a word-play on Quantum Bayesianism and Cubism — is unique among its contemporaries in that its approach is fundamentally deflationary and subversive. Rather than proposing a vision of material reality upfront, QBism questions the world-view implicit in all other interpretations according to which the quantum formalism is to be explained in terms of a mind-independant material world. By taking the embodied lived experience of agents as its primary metaphysical posit, QBism argues that the quantum formalism can be derived as a normative structure regulating the agent’s decisions and actions. By this deflationary, eliminative approach, QBism is able to dissolve many of quantum theory’s apparent paradoxes. Instead of parallel universes or non-causal relations, QBism finds that the essence of quantum theory is simply that the world is “sensitive to our touch”, meaning that the way in which we measure something actively contributes to what is measured. While this insight may seem mundane or even obvious, its implications are far- reaching. For by linking physical reality to the structure of conscious experience, QBism opens the door to a radical integration of the physical sciences with the introspective sciences of life and the mind.