Psychedelics and Consciousness: Distinctions, Demarcations, and Opportunities

Introduction

Yaden and colleagues frame the paper by noting renewed scientific interest in psychedelic substances and their striking effects on subjective experience. They observe that some commentators and popular books suggest psychedelics might illuminate the nature of consciousness, but they caution that the term "consciousness" is used in multiple, often conflated ways. The authors set out to clarify these different senses of consciousness and to evaluate what psychedelic research can and cannot reasonably contribute, distinguishing between the so-called "hard problem" (explaining phenomenal experience itself) and a variety of "easy problems" (mechanistic questions about perception, attention, selfhood and related contents of consciousness). The review aims to assess philosophical distinctions, neuroscientific models proposed to explain psychedelic effects, and empirical findings about subjective psychedelic states. Throughout, the investigators emphasise the need for epistemic humility: to separate modest, testable scientific claims about the contents and functions of consciousness from stronger claims about solving the hard problem of how subjective experience arises.