Reconciling Mystical Experiences with Naturalistic Psychedelic Science: Reply to Sanders and Zijlmans

Sanders and Zijlmans recently argued that psychedelic science should be demystified because concepts such as the mystical experience appear to conflict with a naturalistic, empirical approach. They highlighted that instruments like the Mystical Experience Questionnaire (MEQ-30) probe items such as transcendence of space and time, unity, sacredness and ineffability, and warned that such framing may bias participants and therefore pose both methodological and ethical problems—especially for participants who identify as nonspiritual. Jylkkä replies to that Viewpoint by arguing that the subjective aspect of psychedelic experience deserves philosophical as well as scientific attention. Rather than denying or reducing mystical reports to mere neural events, the author proposes treating metaphysical insights arising in psychedelic states as philosophical intuitions that can be evaluated for truth or falsity. To illustrate this reconciliatory stance, Jylkkä discusses how unitary experiences and panpsychist-type intuitions can be given conceptualisations that are compatible with a scientific worldview.

This paper is a philosophical reply and conceptual analysis rather than an empirical study. The author uses argumentation drawn from philosophy of mind and references to prior empirical and historical literature to evaluate the conceptual relationship between mystical reports in psychedelic research and naturalistic science. Key elements of the approach include: analysing the epistemic status of subjective experience (the so-called epistemic gap), examining the characteristic ineffability of mystical states, critiquing the potential bias introduced by instruments such as the MEQ-30, and surveying philosophical frameworks (for example, Kantian limitations on knowledge, monism, and panpsychism) that could accommodate mystical intuitions without abandoning a naturalistic methodology. No new quantitative data, experimental procedures, or formal empirical methods are reported in the extracted text.

Jylkkä advances several interrelated claims. First, subjective experiences—mystical experiences included—are felt as real by subjects and can produce personally meaningful insights; their felt truthfulness (what William James called "noetic quality") should not be reflexively dismissed. Second, there exists an epistemic gap between subjective experience and objective description: knowing all the neurophysiology associated with a state does not convey what the state is like from the first-person perspective, and this gap implies a form of ineffability common to all experience. Third, ineffability and the epistemic gap do not inherently conflict with naturalism. The author points to naturalistic philosophical strategies, including Kantian-style limits on knowledge and monistic formulations of physicalism, that allow for scientific modelling of consciousness without collapsing subjective content into model syntax. Fourth, questionnaires such as the MEQ-30 can bias participant interpretation and thus raise methodological and ethical concerns; Jylkkä concurs with Sanders and Zijlmans that more neutral psychometric instruments are needed. Fifth, some mystical insights—illustrated by the felt sense that "all is one" or metaphors such as being "waves in a sea of consciousness"—can be mapped onto philosophical positions like monism or panpsychism, which can be formulated so as to be compatible with scientific practice. Finally, the author emphasises that whether such metaphysical claims are true is a distinct philosophical question; neuroscientists can model and report the correlates of mystical experiences but should refrain from adjudicating their metaphysical veracity.

The author interprets these arguments to mean that psychedelic science must balance two commitments: methodological naturalism in empirical inquiry, and respect for the subjective, worldview-forming status of psychedelic insights. Jylkkä positions this reply as a corrective to a too-strict demystification that would ignore or erase participants' philosophical intuitions. In relation to earlier literature, the paper situates mystical experiences within long-standing philosophical debates about consciousness and notes historical instances in which altered states informed philosophical proposals (for example, references to William James and Aldous Huxley). Limitations and uncertainties are acknowledged by treating the truth of metaphysical insights as an open philosophical question rather than an empirical conclusion. The extracted text also recognises the methodological problem that current instruments may lead subjects to interpret experiences in particular ways, and therefore it endorses the development of more neutral measures. For practice and future research, the author suggests that investigators should neither reduce participants' worldviews to brain processes nor uncritically accept metaphysical claims; instead, researchers should model experiences scientifically while engaging with the philosophical implications of those experiences. The paper does not present empirical tests of these proposals.

Jylkkä agrees with Sanders and Zijlmans that psychedelic researchers should create more neutral psychometric tools, but cautions against ignoring the subjective and metaphysical dimensions of psychedelic experiences. The concluding position is that such insights should be treated as philosophical intuitions—part of subjects' worldviews and potentially true or false—rather than being fully psychologised or dismissed as supernatural. Determinations about their veracity remain philosophical questions and do not preclude scientific modelling of the experiences themselves.