Alisa Bokulich (Boston University): “Losing Sight of the Forest for the Ψ: A Call for a Successor to the Realism Question”

Abstract: Traditionally the realist project in quantum theory has taken one of two forms: First, defending one of many different possible interpretations of quantum theory as the one true depiction of reality. Second, defending what has been termed wavefunction realism, according to which ordinary space is an illusion and we in fact live in a 3N-dimensional configuration space, where N is the number of particles in the universe. Neither of these projects has managed to produce a broad consensus, in striking contrast to the near universal agreement that quantum theory is one of the most successful theories ever devised. In recent years there has been a shift in the physics community away from a focus on the search for a ‘theory of everything’ towards an emphasis on the importance of effective theories. In this talk I explore how this effective-theory mindsight might help us transform our philosophical debates about realism. As a way of regaining sight of the proverbial ‘forest,’ from what I argue has been an excessive focus on the Ψ, I will examine hydrodynamic representations in physics across many scales. In particular, I will focus on the different representations of the quantum state that one finds in both Eulerian and Lagrangian quantum hydrodynamics. I conclude that the largely stagnant project of depiction realism in quantum theory should be replaced with the pluralist project that I label inferential realism.

Alisa Bokulich is a Professor of Philosophy and Director of the Center for Philosophy and History of Science at Boston University.