Commentary: Not in the drug, not in the brain: causality in psychedelic experiences from an enactive perspective

Abstract

Commentary on: Meling D and Scheidegger M (2023) Not in the drug, not in the brain: Causality in psychedelic experiences from an enactive perspective. Front. Psychol. 14:1100058. doi: 10.3389/fpsyg.2023.1100058 Word Count: 992 Figures and Tables: none We welcome with great enthusiasm Meling & Scheidegger (2023) (henceforth "M&S") timely contribution to advance an enactive approach to psychedelic therapy, especially to the complex causality involved. Their two main research questions concerned: i) the causal interaction between the psychedelic molecule and brain activity; and ii) the causal interaction between brain activity and the psychedelic experience. While we largely agree with and celebrate much of what is proposed by M&S, especially their employment of key enactive concepts to advance our understanding of the first research question, in the following, we will present some worries regarding their answers to the second. Although we agree that there is probably a two-way reciprocal relationship between neural activity and experience, we have several points of contention regarding M&S's proposal. Our hope is to stimulate discussion on M&S's important contribution, and to help advance a much-needed enactive science of psychedelics. Brain activity and psychedelic experience: dynamic co-emergence and circular causality A concept that figures prominently in M&S's account of the relationship between brain activity and the psychedelic experience is dynamic co-emergence (henceforth "DCE"). A first worry is that DCE applies to the relationship between autonomous wholes and their parts (Thompson, 2007), but it is not clear that this mereological relationship holds for consciousness and brain activity. Arguably, the parts of a given psychedelic experience taken as a whole during certain time interval (e.g. the experience of being dissolved into a cosmic unity), are phenomenal parts, (e.g. feeling united to something greater, one's sense of self being disrupted, accompanying visual images, sounds, bodily sensations, thoughts, etc.), rather than local neural activity. Additionally, regarding the latter (i.e. neural parts), the corresponding whole is more plausibly a neural whole, i.e. global brain activity such as interhemispheric synchronic gamma oscillations, rather than the experience itself. A second issue is that M&S treatment of DCE suggests that it is equivalent to circular causality, characterizing both in terms of global-to-local and local-to-global determination. However, they are related but distinct notions. While DCE is meant to describe the reciprocal, constitutive relationship 44 between parts and wholes in autonomous systems (Thompson 2007), circular causality characterizes 45 the reciprocal, but causal relationship between them (Haken, 1983;Kelso, 2021 (Maturana and Varela, 1980). Hence, there is a sense in which a protein molecule 58 produced inside the cell may be said to have "emerged from the whole" or be "specified by the 59 whole". However, when applied to a brain network, it is far from obvious how to make sense of 60 DCE. While it seems very plausible that a neuron behaves differently depending on whether it is part 61 of a system A rather than a system B, (i.e. an instance of global-to-local causality), it seems less 62 plausible to hold that a neuron emerges from or is constitutively specified by the neural system it 63 belongs to. Intuitively, a neuron remains being a neuron even if it were hypothetically isolated before 64 being incorporated into, or after being separated from, a larger neural system, as long as it can remain 65 potentially functional and structurally intact. 66 67Fourth, in order to advance an enactive psychedelic science circular causality should be formalized to 68 make it a scientifically useful tool. To the best of our knowledge, the mathematical, dynamical 69 approaches to circular causality that are most close to the enactive approach are the ones from Haken 70(1983) and Kelso (2021). Nonetheless, close attention should also be paid to formal accounts of 71 causal emergence and downward causation from complexity science and information theory (