Is the life-world reduction sufficient in quantum physics?

Abstract

According to Husserl, the epochè (or suspension of judgment) must be left incomplete. It is to be performed step by step, thus defining various layers of “reduction.” In phenomenology at least two such layers can be distinguished: the life-world reduction, and the transcendental reduction. Quantum physics was born from a particular variety of the life-world reduction: reduction to observables according to Heisenberg, and reduction to classical-like properties of experimental devices according to Bohr. But QBism has challenged this limited version of the phenomenological reduction advocated by the Copenhagen interpretation. QBists claim that quantum states are “expectations about experiences of pointer readings,” rather than expectations about pointer positions. Their focus on lived experience, not just on macroscopic variables, is tantamount to performing the transcendental reduction instead of stopping at the relatively superficial layer of the life-world reduction. I will show that quantum physics indeed gives us several reasons to go the whole way down to the deepest variety of phenomenological reduction, may be even farther than the standard QBist view: not only reduction to experience, or to “pure consciousness,” but also reduction to the “living present.”