Quantum reality: A pragmaticized neo-Kantian approach

Manuel Bernardo Muñoz Bastias

This chapter repeats for quantum mechanics the comparison carried out for relativity in Chapter 5. Its thesis is that the same three interpretative families, neo-Kantian, empiricist and scientific realist, reappear in the philosophical reception of quantum mechanics, but in a more radical form, because the dispute now reaches the meaning of the quantum state, of probability and of measurement. The chapter first identifies what the formalism established in Chapter 4 leaves open and treats the Copenhagen framework as a point of departure rather than a unified doctrine. It then reconstructs the neo-Kantian interpretation (the Kantian affinities of Bohr’s complementarity, Cassirer, Grete Hermann and contemporary transcendental perspectives), the empiricist interpretation (Heisenberg’s observability principle, instrumentalism, Schlick, Frank, Reichenbach and van Fraassen’s constructive empiricism) and, on equal terms, the realist interpretation: Einstein and the EPR argument, Popper’s propensities, the de Broglie–Bohm theory, Bell’s beables and local causality, realist modal interpretations, and the Everett and collapse programmes. The realist family is the most developed of the three in quantum mechanics, but it is also internally plural: it affirms that the theory refers to a mind-independent reality while disagreeing about whether that reality consists of particles, fields, propensities, branching worlds or definite and possible properties. On this basis the chapter compares the three interpretations of causality and of stationary action. Causality appears as a relativized condition of objective description, as a statistical relation without surplus content, or as an objective but non-local structure; stationary action appears as a coordination axiom of quantum dynamics, as an empirically equivalent formulation, or as a real dynamical structure that in Bohm’s theory directly guides motion. The result confirms the pattern of Chapter 5 and identifies the precise point, the relation between quantum possibility and actuality, from which the BBMT bridge of Chapter 7 will start.

Harald Atmanspacher A, Hans Primas

Doug Porpora

M. Anthony Mills

Darrin W.S. Belousek

Florian J. Boge

As it stands, QBism faces two problems, an epistemic and a semantic one: That it is unclear how, on QBism, an agent can coherently abduce the existence of others and an external, mind-independent world, and that it is unclear how talk of that world even becomes meaningful within the QBist framework. I will here go into elements of phenomenology that could potentially help in solving these problems, but also into what I see as their limitations within ‘phenomenology proper’. I will then go back to Kant, in whose writings some of these phenomenological ideas are rooted, and make a big leap forward, in suggesting a broadly ‘neo-Kantian’ constructivism that I believe evades both problems.