Elsevier

Medical Hypotheses

Volume 85, Issue 1, July 2015, Pages 85-93
Medical Hypotheses

Epistemological implications of near-death experiences and other non-ordinary mental expressions: Moving beyond the concept of altered state of consciousness

https://doi.org/10.1016/j.mehy.2015.04.004Get rights and content

Abstract

During the last decades an increasing interest has developed in the so-called altered state of consciousness (ASCs); among these, near-death experiences (NDEs) are one of the most intriguing and debated examples. NDEs are deep and universal experiences with a clear phenomenology and incidence, while some of their features challenge the current views of human consciousness (focused on neural circuits and based on the concept of mind as a byproduct of brain circuitry) with relevant epistemological and historical implications.

The origin of the ruling mechanist–reductionist paradigm can be traced back to Descartes’ radical separation of res cogitans and res extensa and the conflict between the nascent science and the Inquisition; this led to removing the subjective properties of mind from the field of scientific interest, relegating them to philosophy and theology in order to enable the development of modern science. However, the physics of the 20th century has eventually moved beyond the classical paradigm, permitting a profound renewal of scientific interest in the mind.

Modern research on NDEs has contributed to reopening the debate surrounding the Cartesian separation, the mind–brain relationship and the nature of consciousness. It is now time to reappraise the relevance, strengths, and weaknesses of the available scientific interpretations of NDEs, their relationship with other ASCs, as well as the very concept of ASC; the latter looks to be ill-founded, suggesting the need for: (a) a revision of the conventional approach to subjective phenomena, including both the third- and first-person perspective; and (b) a deep reflection on the possible links between different non-ordinary mental expression, as regards both their phenomenology and mechanisms from a non-pathological perspective.

Introduction

The term “altered state of consciousness” was coined by Ludwig, who first defined it, as “any mental state representing a sufficient deviation in subjective experience or psychological functioning from alert, waking consciousness” ([1] p. 225). To date, the classification of altered state of consciousness (ASCs) includes a wide range of experiences, including coma, persistent vegetative state, delirium and hallucinations. Within the wide range of ASCs, near death experiences (NDEs) represent one of the most investigated phenomena in the last three decades. Indeed NDEs invite important scientific, philosophical and religious reflections and their nature represents a true challenge for modern neuroscientists.

NDEs are subjective experiences with transcendent tone that occur in critical conditions, usually associated with loss of consciousness, such as in cardiac arrest, head injury, or states of shock. They are often characterized by the clear perception of being in a different dimension, of having left the physical body, and of being in a different spatio-temporal dimension (see Table 1 for a list of the main recurring features). Even though some cross-cultural differences in some recurring features have been described, overall the reports show sufficient common features around the world to be considered a universal human experience, making the phenomenon of interest for modern neuroscience [2], [3]. The incidence of NDEs is relatively high, being in the range of 10–18% of patients in critical condition [4], [5], [6], [7], showing that they are a reproducible clinical phenomenon with clear clinical epidemiology rather than a sporadic event. The exact incidence is unknown because NDE accounts are usually not collected by the medical staff, while many patients prefer not to report their experiences, or decide to describe them exclusively to doctors who are familiar with this issue, to avoid to be considered still highly confused following the injury [8]. As claimed by Auxéméry [9], the increasing number of NDE cases, as well as the dilemma of possible persistence of residual consciousness in comatose and vegetative patients (see [10] for a review), urges one to re-think the interaction of medical teams with seemingly unconscious patients: they should not act as these patients were not there, but, conversely, as subjects (despite non-communicating) to whom one speaks.

Section snippets

Scientific interpretations of NDES

In recent years several psychobiological interpretations have been proposed, but none of them has been proved so far, while some of them are contradicted by the available data (see [11], as a review). For instance, it was suggested that retinal ischemia might explain the tunnel-like vision [12]. Since endogenous opioids are released under stress (e.g., during hemorrhagic shock) they have been postulated as a potential reason for the positive emotional tone of NDEs. Likewise, the excitotoxic

Historical roots and epistemological implications of the issue

Secular scientific thought has generally disregarded phenomena with a flavor of spirituality or religion and ignored philosophical/religious problems, since they have been considered beyond the boundaries of the positivist view of physical reality. This has led, perhaps unwittingly, to considering such phenomena a priori as irrelevant or unreal, rather than simply beyond the current interests and techniques of scientific investigation. Such an attitude, the prejudicial nature of which is

From ASC to NOME

The above discussion lays the basis for a revision of the very concept of ASC. Table 2 illustrates how the term ASC has been used to include a number of experiences and mental phenomena of differing nature and meaning. The adjective “altered” often implies a general attitude toward all these conditions as not only different from, but deficient compared to, ordinary waking consciousness, which is considered the only “non-altered” state. But whereas sleep, a physiological activity in which we

Towards a new approach

It is time to reassess the nature of NDE within the broader range of spiritual experiences and reconsider the foundations of this complex topic from an open perspective able to encompass all NOMEs, together with their still misunderstood physiology. Such a multidisciplinary perspective should help create a common language for neuroscience, psychology, philosophy, anthropology, and other disciplines. It should also facilitate a flexible approach that is both top-down and bottom-up at the same

Conflicts of interest statement

The authors disclose that there are no financial and personal relationships with other people or organisations that could inappropriately influence their work.

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