A causal pluralist theory of the interaction of substance, set and setting in psychedelic experience

Psychedelic research has shown that the effects of serotonergic substances, such as psilocybin and LSD, are strongly influenced by the interaction of substance, set, and setting. Mystical-type experiences, often induced by psychedelics, are not solely driven by pharmacological mechanisms but emerge from a dynamic interplay between the psychological state (set), external environment (setting), and the neurochemical effects of the drug. We defend a causal pluralist theory that suggests multiple valid explanations can be offered, including pharmacological, neural, psychological, social, political, and historical explanations of the causal influence of set and setting on the psychedelic experience. A question for pluralism is how causation can occur at the higher-levels of analysis of psychological states (set), and societal and cultural practices (setting). We use concepts from enactive cognitive science as applied to psychedelic experience to answer this question by elaborating on a pluralist notion of causation. A problem for enactive cognitive science is that it has so far failed to yield testable models and predictions about the psychedelic experience. We suggest that the predictive processing theory may be able to fill this gap. We conclude then that a pluralist synthesis of ideas drawn from enactive cognitive science and predictive processing may provide the best set of conceptual tools for making scientific sense of the dependence of the psychedelic experience on set and setting.