Several theories have been proposed to explain out-of-body experiences (OBEs). Essentially and oversimplifying, the main OBE theories – which account today for more than 40 theories – are generally linked to five types of explanations:
1. Pathological theories: These suggest that OBEs are linked to mental illnesses.
2. Psychological theories: These theories propose that OBEs are either a type of hallucination or delusion caused by psychological factors such as stress and anxiety.
3. Physiological theories: These suggest that neurophysiological changes in brain activity cause OBEs.
4. Spiritual theories: This theory suggests that OBEs are spiritual or metaphysical experiences that allow a person to connect with a higher reality.
5. Quantum theories: although, except for a few fringe exceptions, there is a lack of an expressed link between theories of consciousness proposing consciousness to be related to quantum phenomena (brain-consciousness interaction) and OBEs, these theories are often loosely transposed to explain the OBE state in the internet (a review of which is beyond this essay).
Although the above OBE theories and their categories have usually been an exclusively one-sided explanation (e.g., psychological or physiological), a general phenomenological reductionism has often led such theories to be often blind to the overall phenomenology ascribed to such experiences, which in fact, – excluding pathological theories –, indicates that psychological and physiological factors may have varying causal influences on these experiences for different people. Even that, a physiological condition predisposing to an OBE is not necessarily reductionist and does not imply it is not governed by any other subjacent mechanism, psychological or spiritual. All in all, such complexity of factors is corroborated by studying the phenomenology of OBEs in narrative reviews. But can these states be correlated to any quantum theory?
"The founders of quantum mechanics made the revolutionary move of bringing conscious human experiences into the basic physical theory in a fundamental way. In the words of Niels Bohr the key innovation was to recognize that 'in the great drama of existence we ourselves are both actors and spectators'" (Stapp, 2005, in Kelly, 2007). If that is the case, can OBE perceptions be affected similarly? For example, there are some instances where some experiencers report a sort of undefined "entangled" state of consciousness. These are reported during OBE-onset (e.g., the initial exteriorization of the consciousness) and are described as "double perception", a "perceptual cleavage", and a "sense of spatial duality" often expressed as the sensation of being at two places at the same time, – which do not resemble dissociative states. Certainly, in such cases, a quantum brain-consciousness interaction theory could hypothetically explain such experiences through the quantum theory of entanglement, a phenomenon in which particles become linked and can influence each other's behaviour even when separated by large distances, and which has been theorized to explain psi abilities of the consciousness; however, not all OBEs involve the perception of the physical body at the onset. In fact, most often than not, experiencers do not have any perception or feelings about their physical body while having an OBE. Can these OBE cases, whereas the experiencer perceives him or herself literally out-of-the-body, far from the body, always be seen ontologically as a quantum state from a purely experiential perspective? In other words, can such an OBE state be related to quantum physics?
Quantum physics studies the behaviour of subatomic particles, such as electrons and photons, to understand the properties of matter. In doing so, it relies heavily on probability to observe and detect these particles. The corresponding probability functions which allow these studies are formulated into Schrodinger's equation and aim at explaining the behaviour of the particles in terms of their probabilistic quantification. Such quantification allows quantum mechanics to represent the probability of finding a system to be in a particular state (e.g., the wave function). As such, the Schrödinger equation is used to describe the behaviour of particles such as electrons in atoms, molecules, and solids. Applying such a quantum paradigm to explain the OBE state would mean presuming that the same rules apply to the reality experienced in OBEs. However, most OBE (not all) report perceptions governed by deterministic conditions, such as those reported by the laws of the macroscopic world, not by quantic indeterminism. For example, in experiences expressing a high degree of awareness, the astral body is often perceived to have a physical materiality. Assuming a metaphysical reality would equally mean that not only such a reality is governed by the same sub-particles exhibiting the same properties, but the manifestation of consciousness – often accounted to be experienced in OBEs through the metaphysical body (e.g., astral body) – would need to be, similarly, physical in nature (Monist position). Certainly, either way, if the properties of the OBE experience may often be perceived as physically as the experience one perceives in their normal waking state, we can only presume the possibility (e.g., that the same sub-particles govern these assumed realities).
To that extent, not many experiencers, even the most experienced, account in detail about the physical properties of the body they are experiencing out-of-body with. Nonetheless, one common denominator of OBEs accounted for by many experiencers – from an experiential perspective – is the perception of light, either expressed for the perceived environment or the physical reality of the metaphysical body. If the above presumptions would be correct, then because light exhibit quantum properties described by principles of quantum mechanics, the OBE state would have, in essence, a hypothetically similar ontological quantum property as the one expressed in physical reality. That is, the manifestation of consciousness out-of-body would express a physical quantum characteristic. Possibly to a higher degree than in physical reality.
On the other hand, as stated, the general physical and locality of some OBEs, suggested by many accounts, do not always indicate a condition of entanglement. Either through the perception of the body or as a communion with the perceived universe. Certainly, if quantum theories of consciousness could theoretically propose an entanglement theory to explain why the consciousness remains connected even when it is separated from the body (which would make redundant the astral cord), any such theory would not explain OBEs without perceived entanglements (e.g., where an egocentric locality and agency are reported) . However, the same state of quantum entanglement could be better suited and proposed to explain the perceptions of non-dual awareness, associated or not with oceanic feelings, during OBEs (which in these cases could not be monistic).
A more complex and interesting OBE-quantum perspective can be further theorized. If both the ontological reality of OBEs and the hypothetically assumed metaphysical reality of the astral body (e.g., the manifestation of the consciousness through the astral body) express a potential quantum state, our perceptions during OBEs would also be quantum-like. Indeed, non-local interconnectedness, as suggested by Bell's theorem of quantum mechanism, hints that at the quantum level, particles cannot be localized in space and time (e.g., particles are non-local) and, as such, they are particles expressing the potential of a field or possible state of a system, called the "quantum phase space". Considering the previous theoretical assumptions, we could hypothesize that such a field could be influenced by OBE perception (i.e., collapsing of the wave function). This condition could explain spontaneously evoked OBE perceptions which are perceived as real objective expressions of the psyche and the perceptual differences in Near-Death Experiences. In essence, the consciousness would force the field to have a concrete outcome.
Finally, it should be emphasized that only a few psychologists and neuroscientists would venture into any conceptual theorization of the fundamental significance of quantum theory in such fields. Much less any OBE quantum theory. And for a reason. Extrapolations of classical quantum concepts, such as the one made here, are indeed approximations of the actual concepts of quantum physics and are naturally sufficient to engage the concerns of physicists who are themselves often conceptually overwhelmed by such theories. Specifically when they are made by non physicists. Furthermore, any of the assumptions made here are simply inferred from experiential perspectives (for a review see Montenegro, 2015). As such, such theoretical assumptions should be assumed to be free extrapolations of narrative reviews and as speculative as the aforementioned OBE quantum theories. Indeed, none of these theories has ever been extensively studied or tested, and there is currently limited empirical evidence to support the idea that OBEs are ontologically governed by quantum mechanisms (e.g., through brain-consciousness interactions) or express any quantum phenomena such as entanglement. Any such quantum theory of OBEs may be difficult to test or confirm using current scientific methods (verifiability). Certainly, we will need first a much better understanding of what is happening in the brain during OBEs to get there and test any such theories. But we will get there.
Sleep Consciousness Researcher,
Kelly, E., F., et al. (2007). Irreducible mind: towards a psychology for the 21st century, Rowan & Littlefield Publishers, Inc.
Montenegro, R. (2015). The Out-of-Body Experiences – An Experiential Anthology, Imagens & Letras.
Radin, D. I. (2006). Entangled minds: extrasensory experiences in a quantum reality. New York, Paraview Pocket Books.
 Assuming such a theory can be used to explain all macroscopic systems that are fundamentally at the center stage of brain systems which behaviour depend on their atomic constituents (e.g., ion channels; synaptic clef).  Indeed, the behaviour of light and other electromagnetic waves is described by the theory of Quantum Electrodynamics (QED) as made of photons and governed by the principles of quantum mechanics, being able to exhibit both wave-like and particle-like behaviour.  Which would mean we would apply a “local theory” of physics to such a state. A "local theory" is a theory that assumes that particles have definite properties (such as position, momentum, or spin). In this sense, we can say that a local theory is a completely opposite theory to quantum entanglement.