An Examination of its Phenomenology, Philosophy and Neuroscience
Dr Daniel J Hall, CT2 Psychiatrist
Researchers in neuroscience are increasingly interested in altered states of consciousness and what they tell us about our phenomenal self. Just as the classic case of the unfortunate railway worker Phineas Gage offered insights into basic neurology, so it is hoped that altered conscious states can provide insights into the structure of conscious experience. Already progress is being made, experiments into out of body experiences, investigations of dream states, of rare neurological diseases and of psychotropic drug use, all suggest that valuable information can be gained by the examination altered states which could possibly lead to new clinical interventions (Metzinger 2004).
One fascinating altered state lies within spiritual practice, namely the enlightenment experience central to Buddhism. Mystical experiences as occurring within spiritual traditions have been known to human beings for the entirety of recorded human experience, from the folk shamanism of pre-historic humans through to the sophisticated religions of agrarian civilisation. Indeed it estimated up to 90% of cultures have some institutionalised form of mystical experience (Walsh 1993). In the West such experiences are rarely talked of, this author can think of several reasons why this might be so:
- Historical – Western Christianity has traditionally placed little emphasis on personal mystical experiences.
- Scientific – The modern tendency is to interpret such experiences as pathological, especially within the lens of biological neuropsychiatry where any unusual experiences, especially ones with religious undertones, are seen as psychopathological and deviant from normal. There is a low tolerance in general throughout Western civilisation for any unusual conscious states.
- Cultural – Secular Western civilisation associates such experiences with the 'Exotic Orient', drug use and New Age practices, generally thought of as fringe, embarrassing and out of place in a modern technological civilisation.
This is despite 49% of Americans reporting experiencing a mystical experience in the past year (Pew Research Centre, 2009). As clinical psychologist and Buddhist monk Jack Kornfield (2008) points out most of these experiences occur by accident through psychedelic drugs, sexual climax, near death experiences etc., very few Westerners engage in deliberative spiritual practise for mystical experiences. Lukoff (1985) also quotes survey results suggesting one third of Americans report mystical experiences and highlights that these are not rare phenomena; mental health clinicians need to be aware of them.
The concept of Enlightenment emerges as central within the post-Vedic family of religions located in Northern India such as Hinduism, Buddhism and Jainism. Enlightenment is a diverse and complex concept, especially within Buddhism which is notorious for its intellectual esotericism and proliferation of traditions. However, a central component of enlightenment tends to be a mystical experience of great profundity to its experiencer and it is this I intend to focus on. Within Buddhism talking about such experiences tends to be taboo, however recorded examples do exist. I will provide some Enlightenment examples within the Buddhist tradition focussing on their phenomenological aspects, then Buddhism's philosophy of such experiences and finally offer a brief exploration of their current position within neuroscience and clinical practice.
Phenomenology of Mystical Experiences of Enlightenment
In Buddhism the original enlightenment experience is that of its founder Siddhartha Gautama. The term Buddha itself means awakened one, referring to the fact of enlightenment. The story of Gautama's transformation from Prince to Enlightened Being is a historically enigmatic legend which many children learn in school. Classically the story goes that he was the son of a King who lived a life devoid of suffering. Then, at the age of 29 he escaped his palace and witnessed a poor man, a sick man and a dead man; realising that death, illness and suffering were inevitable, he fled and became an extreme ascetic for many years. However, finding no liberation through his ascetism, he one day accepted food and sat under a Bodhi tree refusing to leave until he became enlightened (Blomfield 2011). Closer to reality, Siddhartha likely originated at the ruined city of Kapilavastu on the Nepal-Indian border and was probably the privileged son of a local Shakyan noble (Shakya being the region where Gautama was born). He seemingly spent most of his life touring the then heavily forested Ganges valley as a teacher or sage in the spirit of the multitude of wandering ascetics and holy-men of that time (Blomfield, 2011). The enlightenment event itself has become mythical; some stories describe Gautama dramatically battling the symbolic demon Mara to overcome his aversions and desires, other sources describe how he entered ever more concentrated states of mind until he entered a state of almost complete cessation, called Nirodha and later the Buddha's description of Nirvana – meaning to 'blow out'.
Luckily we have more modern descriptions of individuals said to have experienced enlightenment to draw upon. I have selected six modern day vignettes of enlightenment experiences from various Buddhist practitioners to review:
1. The experience of Zen Master Sokei-an Sasaki:
“One day I wiped out all the notions from my mind. I gave up all desire. I discarded all the words with which I thought I stayed in quietude. I felt a little queer – as if I were being carried into something, or as if touching something power unknown to me….and Ztt! I entered, I lost the boundary of my physical body. I had my skin, of course, but I felt I was standing in the centre of the cosmos. I spoke, but my words had lost their meaning. I saw people coming towards me, but all were the same man. All were myself! I had never known this world. I had believed that I was created, but now I must change my opinion: I was never created; I was the cosmos; no individual Mr Sasaki existed.” (Watts 1989)
2. The experience of Zen Priest Brad Warner:
"I was walking along the road and just about to cross the bridge when all my problems, all my complaints, all my confusions and misunderstandings just kind of untwisted themselves and went plop on the ground....The universe was me and I was it. I looked up at the sky and that experience was exactly like looking in the mirror." (Warner 2005)
3. The experience of Zen practitioner Stephen Gray:
“All of a sudden I was instantly in a different…. I don't even know what to call it….instant… a different dimension, I wasn't aware of my body anymore, absolute darkness - total infinity of black – and, I wasn't even there anymore, there was just this infinite open sort of black space. And, after a while what I could feel were like these insights, almost being downloaded through the top of my head into my body like a computer programme was being downloaded…they were coming like a hundred a second, just way too many for me to have conscious…but I knew they were insights just like if you could imagine like 'ahas' going of like a popcorn popper, but so quickly you couldn't stop to recognise what you just realised; so there was this downloading almost like information like 'ahas'; and then almost slowly after more time I became more aware of my body, the energy had settled and after a while I was just sitting there - totally normal - absolutely no high no low no, it's all just Shooooo! I'm just sitting there and I think well… there's nothing left to do, I guess I'll get up!” (conscioustv 2018)
4. The experience of an anonymous Buddhist practitioner:
“It was the middle of a long retreat. I had been following the breath at the abdomen for three week with continuous noting: “in, out, touching.” In one sitting there was a deep sense of calm followed by the grasping of that calm. Immediately and without any effort on my part the thought arose: “grasping.” I wondered with great curiosity: 'who knew that?' Then there was an abrupt transition. A subtle vibration of unmoving peace stood out from the background. The foreground fell away: there were no mental formations and no consciousness of the body or physical senses. But some kind of awareness continued. Because perception wasn't operating it's impossible to say what was being known. But some unshakeable peace was revealed which had been there all along, totally uncaused.” (Armstrong 2017)
5. The experience of an anonymous Zen practitioner:
The next morning, just after breakfast, I suddenly felt as though I were being struck by a bolt of lightning and I began to tremble. All at once the whole trauma of my difficult birth flashed into my mind. Like a key, this opened dark rooms of secret resentments and hidden fears which flowed out of me like poisons. Tears gushed out and so weakened me I had to lie down. Yet a deep happiness was there…Slowly my focus changed “I'm dead! There's nothing to call me! There never was a me! It's an allegory, a mental image, a pattern upon which nothing was ever modelled!” I grew dizzy with delight. Solid objects appeared as shadows and everything my eyes fell upon was radiantly beautiful. (Kapleau 1989)
6. The experience of an anonymous Zen practitioner:
All at once the roshi [Zen Buddhist priest], the room, and every single thing disappeared in a dazzling stream of illumination and I felt myself bathed in a delicious, unspeakable delight…For a fleeting eternity I was alone – I alone was… Then the roshi swam into view. Our eyes met and flowed into each other, and we burst out laughing…'I have it! I know it! There is nothing, absolutely nothing. I am everything and everything is nothing!' (Kapleau 1989)
These six examples, primarily drawn from the Zen Buddhist tradition highlight moments of awakening. Unfortunately demographic details are not known for all of them but all apart from (5) are male. They are a mixture of Japanese/American practitioners and ages are unknown.
Immediately what arises is the sense of ineffability, often experiencers have great difficulty describing what occurs, so much so that in (1) and (3) they're reduced to exclamations like “Ztt!” and “Shooo!”. Also present is a strong sense of ego dissolution with the loss of somatic presence and of physical boundary coupled with autoscopic phenomena such as the dopplegänger experiences described in (1) and (3). Although in the vignettes the somatic boundary of the self is lost, there is still a sense of in-der-Welt-sein, of being present in a phenomenal world at some level, even though, perceptually that world is devoid of most normal 'internal' (e.g. thought) or 'external' (e.g. world-building) perceptual content. Experiencers may experience only a basic sense of space, sometimes either black or light filled as in (3), (4) and (6). There is a pantheistic, oneiric experience throughout all of them, a sense of deep and dreamy union with the cosmos, probably catalysed by the weakened self. There is a diminishment of temporality throughout the event; the ordinary temporal vividness of waking human experience is lost. Paradoxically (paradox being a classic feature of the mystical experience) there might also be a feeling of instantaneity to the event, a “fleeting eternity” as described in (6) – there is the sense, at least post-hoc, of interpreting the event as occurring within time.
Interestingly, although there is a paucity of perceptual content especially around 'external' world building, there remains an emotional richness. Affectively we see a profound sense of equanimity in the experiencers as in (4) describing “a deep sense of calm”. Frequently there appears to be immense joy as in (5) and (6). Ironically there may also be a profound feeling of cataclysmic change, as if the rug has been pulled from beneath reality or as if suddenly awakening up from a dream. This is the noetic quality of enlightenment experiences, a feeling of revelation, of fundamental truth intuitively revealed that fits classically within the Buddhist paradigm of no-self, see (1) where “No individual Mr Sasaki existed”, (5) “There never was me” and (6) “There is nothing, absolutely nothing” etc. It is interesting to contemplate whether it is the experience itself that leads to the no-self conclusion or prior beliefs and expectations that bias the experience. It leads automatically to the question is there a basic mystical experience unique to human consciousness across all cultures or is the mystical experience culture bound such that the experience itself and post-hoc interpretation always occurs within the practitioners belief system?
Walsh (1993) who comparatively maps altered conscious states found in spiritual traditions to schizophrenia writes: “At the highest reaches of meditation transcendent experiences of a wholly different, radically discontinuous from those that have gone before are said to occur. These are the Samadhi of yoga and the nirvana of Buddhism”. It is phenomenologically interesting to note the difference of the mystical states in out vignettes to the classic psychiatric state of ego disintegration, that of schizophrenia. Walsh (1993) highlights how contrary to the smooth, calm, pleasant state of transcendental ego deconstruction that occurs in mystical states, in psychosis we see disorganisation, agitation, negative or blunted affect with an incoherent reality. Not to mention that shamans and monks tend to be socially adept and powerful members of society, something not seen in the social down drift classic of schizophrenia.
The Philosophy of Enlightenment: No-Self and Emptiness
As highlighted earlier, enlightenment experiences within Buddhism tend to reflect the concept of no-self, referred to in Sanskrit as Anatta. It is well known that emergent self-hood is one of the defining characteristics of human development. By around 18 months at least half of human infants can recognise themselves in the mirror (Upton, 2012). In classic Freudian psychosexual development we see an infant developing ego and super-ego formation. It is a basic fact of life that life is bounded in some way, from a cell membrane to the human integument, there is a sense of separateness from the external world. We are all endowed with a sense of being someone, of being a subjective agent separated from the external world. We feel as if we are inside our bodies, the classic representation is of course as a permanent and independent homunculus behind our eyes, viewing the world and pulling the body's strings. It is often easy to see how this intrinsic folk psychology leads to ideas of selves, souls and the mystery of subjectivity.
Jack Kornfield (2008) writes that "The gift of Buddhist psychology is to take us to the next step...to see beyond the separate self". In Buddhist thinking it is the ability to cease identifying with "I, me and mine" that frees us. Enlightenment is perhaps the ultimate experience of this. Buddhist philosophy primarily sees the self as a delusion, a process of "selfing" driven by identifying with and owning the body, moods, thoughts, pleasant and unpleasant sensations (Armstrong, 2017). It is this that is believed to be the root of human suffering. As Zen Master Shunryu Suzuki states "According to the traditional Buddhist understanding our human nature is without ego. When we have no idea of ego, we have Buddha's view of life". Fundamental to this position is the Buddhist idea of impermanence - that all things change, that there never really is something permanent about your being that you can fully grasp. This is something that modern philosophers are keen to point out, any idea that you are the same person at 9 months that you are at 90 is in one sense completely absurd (Baggini, 2012). Zen master Suzuki (2011) concurs "strictly speaking there is no connection between I myself yesterday, and I myself in this moment; there is no connection whatsoever". This is true is a very real sense, we are in constant physical and psychological flux. Evolutionary psychologist Robert Wright (2017) states that "there are some themes that everyone agrees are part of the Buddhist tradition from early on...And one of these is that our conception of our selves is, at best, wildly off the mark...and much more fluid, with a much less fixed identity than we think".
One cannot underestimate how radical this is, especially arising in Iron Age India of the Buddha's time, with the Ganges valley dominated by folk religions and magical thinking of Brahmanism (Blomfield, 2011). There is a subtle shift of reasoning to understand here; the concept of no-self is not that there is truly no-self, we all have an experience of being someone, and actually as an evolved aspect of consciousness the phenomenal self is an incredibly useful and powerful tool (Metzinger, 2004). Rather, Gautama realised that human beings commit a fundamental category error, in constantly identifying the self (and indeed the whole of reality) as a permanent object instead of as an impermanent process. Gautama himself used the apt metaphor of a flowing, dynamic river to explain this fundamental process ontology to audiences at the time (Blomfield, 2011). This is a paradigm change in thinking; the false idea of a separate permanent self shifts such that the experiencer is themselves an experience within the flow of experience. It's an idea so revolutionary that the West has only recently caught up. One can go back to the start of the Western Enlightenment and see Hume's spookily Buddhist reasoning in the 18th century when he writes "For my part when I enter most intimately what I call myself, I always stumble on some perception or other, of heat or cold, light or shade, love or hatred, pain or pleasure. I never catch myself at any time without a perception and never can observe anything but the perception”. One can easily envision those words uttered by a modern day Tibetan Lama, Zen Master or Gautama himself. Hume could identify nothing but the various drops of experience that constitutes the flowing river of conscious experience itself.
Freud (2002) recognises ego-dissolution states referring to them as "oceanic feelings". Freud originally envisions the ego as an all-encompassing state but as the infant matures, develops and separates from the mother's breast this symbolic unity is lost, and "our present sense of self is thus only a shrunken residue of a far more comprehensive, indeed all-embracing feeling which corresponded to a more intimate bond between the ego and the world around it". Freud however is ultimately dismissive and views this unity as a somewhat vestigial remnant of a more primitive past. Contrary to Buddhist thinking where Zen master Suzuki (2011) refers to this oceanic sense as "big mind", with the theme in Buddhism nearly always to see and in a sense annihilate the suffering small-self within a transcendental larger whole. In the vignettes, we see the literal dropping away of self-conscious content to a minimal state, and the realisation empirically of the “oceanic feelings” or “big mind” of a unitive consciousness.
This empiricism is key, as Buddhists mean to realise self-less states not just in an intellectual sense but truly as an experienced one of ego dissolution. Zen master Suzuki (2011) writes "so our understanding of Buddhism is not just an intellectual understanding. Our understanding at the same time is its own expression, is the practice itself". This is achieved through contemplative practice, indeed many of the vignette practitioners had been engaged in meditation for significant lengths of time before their mystical experiences. Historian Conze (2008) points out that central to Buddhist practise from its origins is meditation; the last two parts of the Buddha's eight-fold path are Sati (Right mindfulness) and Samadhi (Right Concentration). In a sense concentration is best thought of as undistractedness, collectedness or one-pointedness; a unified mind without necessarily been focussed on one object in particular (Armstrong 2017). It is in a deep, concentrated and mindful state that awareness of the impermanence and flux of the self arises. In calm, concentrated states the self begins to fall away and the duality of subjective experience dissolves into emptiness. When observing a classic object of meditation, such as the breath, the limits of conscious experience reveal themselves such that one may realise the breath breathes itself, so thoughts think themselves, and feelings feel themselves (Kornfield 2018). Zen monk Jack Haubner Shozhan (2013) writes on his meditative training that its purpose is to "pulverise the very skeleton of ego - upon which the meat and skin of our illusions hang - and we do so through intense, hurtle-yourself-off-the-cliffs-and-into-the-chasm practice." This then, is the self-less, joyous ego dissolved states present in our vignettes, that "when you discover that there is nothing to cling to, and there isn't anybody to cling to them, everything is quite different. It becomes amazing" (Watts 2018).
The Emerging Science and Clinical Application of Self-less states
Milliere (2018) in a review of meditative and psychedelic effects on selfhood highlights that ego dissolution states are notoriously difficult to define and should be thought of as multidimensional incorporating somatosensory, agentive, narrative and social components, dysfunction of any one of these components can be identified as a self-less state (See Figure 1). Certainly in the enlightenment vignettes of this essay we see disruption to some degree of all those components to various amounts. In terms of neural correlates, brain imaging suggests that mystical ego-dissolution states are to some degree correlated to disruption of the default mode network, a power hungry neural network involved primarily in thinking about the self when attention is not engaged in a task. (Milliere 2018; Carhart-Harris 2014). Certainly, when attention is focussed, such as in contemplative practice, self-referential conscious content tends to decrease (Austin 2011).
Figure 1. (Milliere 2018) A hypothetical schematic highlighting the changing phenomenal domains required for ego-dissolution to occur from the normal waking state to self-less psychedelic and meditative states.
Neurologist and long term Zen practitioner James Austin has extensively reviewed neuroimaging research into meditative states catalysed by his own enlightenment experience where on meditative retreat in London; “I happened to gaze casually into the sky and my entire psychic sense of self dissolved…” (Austin 2011). He assembles a functional neuroanatomical model highlighting a balance between two attention pathways within the two stream theory of attention. There is a dorsal, voluntary, ego-centric stream and a ventral, involuntary, allocentric stream. The dorsal ego-centric pathway generates an axial, somatic schema involving the frontal eye fields and creates a sense of what object related to me (and my line of sight). Contrary to the ventral stream, the allocentric pathway, has no frame of reference and no line of sight and is simply concerned with what is. Austin’s hypothesis is that meditation leads to a fine-tuning of attention away from the nearly always dominant subjective dorsal stream with its somatic reference frame and eye level line of sight to the ventral attention stream that has no frame of reference and no line of sight. During an enlightenment experience it is the ventral stream that briefly becomes the dominant attention stream.
Fig 2. (Austin 2011), The first image highlights the dominant dorsal attention stream with its axial somatic self-reference and eye level line of sight compared to the second image highlighting the ventral attention stream which Austin hypothesises dominates during enlightenment experiences and is unconcerned with a central axial somatic reference.
Milliere (2018) reviews the central metaphysical claim of Buddhism, no-self, which he defines as non-dual awareness - a state where the background availability of self-awareness is lacking. He states “the inhibition of self-related thoughts, body ownership, bodily awareness and self-location should entail a blurring or dissolution of the boundary between self and world, and the associated ‘unitive experience’—identified … as the core feature of so-called ‘mystical-type experiences’”. Although there appears to be consensus that such states are real, their exact phenomenal nature remains opaque, partly due to a paucity of neurophysiological scientific data and also the general philosophical and scientific discordancy around the nature of self-consciousness. It is empirically unlikely that a state completely devoid of conscious content at all (such as the phenomenal self) is possible, rather what practitioners experience is an incredibly ‘sparse’ and minimal reality (Milliere 2018).
Inducing mystical states by contemplative practice requires tremendous work by individuals. All of the experiencers in the vignettes had likely engaged in many years of contemplative practice to have an enlightenment experience. The founder of modern day secular mindfulness Dr Jon Kabat-Zinn (himself an accomplished Zen practitioner) – who established mindfulness based stress reduction in the early 70s – has done his utmost to extract the spirituality from mindfulness and leave a, perhaps impoverished, secular mindfulness module to be added onto modern day psychological therapies such as CBT (Kabat-Zinn 2013). Divorced from its spiritual underpinnings as modern mindfulness has endeavoured, would it even be possible to achieve mystical states in a secular setting? How would they be interpreted? What of clinicians? As Watts (2017) wryly states should we ask psychiatrists to “take practical instruction in Yoga, or spend time in a Japanese Zen monastery - adding yet more years of training to medical school, psychiatric residency or training analysis?” The shortcut to years of meditation garnering most interest is the use of psychedelics, a subject which, much like contemplative practice, is undergoing a renaissance.
The investigative journalist Michael Pollan in his new book examining clinical use of psychedelics highlights how much of the research performed with psychedelics has been recovered only recently, with remarkable effects on well-being in patients undergoing treatment for cancer and addiction being observed (Pollan, 2018). Similar in some respects to meditation, current brain imaging suggests that psychedelics have significant cerebral effects, decreasing blood flow across many regions, but especially within the default mode network, which as Milliere (2018) describes has often “dramatic effects on self-consciousness….with a loss of one's sense of self and self-world boundaries, together with a concomitant oceanic feeling of ‘oneness’ or ‘unity’” (Carhart-Harris 2014; Milliere 2018). Carhart-Harris (2014) sees the hyper-egoic, introspectively focussed and rigid states of a lot of psychiatric conditions such as depression, obsessive-compulsive disorder and addiction as therapeutically ripe for the ego-melting, magical states induced by psychedelics. He has a particular psychoanalytic bent to his research and is keen to point out that within the Freudian paradigm psychedelics maybe an extreme form of free association. Prof. David Nutt with a degree perhaps of hyperbole finds in the default mode network we may have discovered the neurological basis of ‘repression’ (Pollan 2018). The growing evidence suggests that mystical and self-less states induced by psychedelics can be profoundly beneficial in a whole range of psychopathologies, primarily by inducing an intense ego dissolved state similar to enlightenment experiences (Milliere 2018; Carhart Harris 2014; Pollan 2018). It needn’t only be for sick people, in one double blind trial of 36 healthy people given a one off dose of psilocybin, 58% reported the experience as one of the five most meaningful of their lives and 67% as one of the most spiritually meaningful (Griffiths 2008).
Even without considering interventions such as meditation or psychedelics, there is one thing clinicians practising today can apply easily, and that is simply to be aware of intense spiritual and mystical experiences. They are not, as highlighted earlier, at all uncommon and Lukhoff (2007) writes “the clinician’s initial assessment can significantly influence whether the experience is integrated and used as a stimulus for future growth, or repressed as a sign of mental disorder….” He notes that it is important for clinicians to be able to recognise a mystical experience as a transient state of consciousness that rarely does long term harm and can be of profound personal significance for someone. The aim of clinical interaction should be normalisation and the consideration of psychotherapy to help explore what has been experienced. As he further notes, the general public’s interaction with contemplative traditions, yoga, psychedelics, drumming circles and other avenues for intense spiritual experiences is only increasing, meaning increased vigilance for clinicians when presented with altered states as seen in our earlier vignettes.
The aim of this essay was to provide a brief review of the mystical state in Buddhism known as Enlightenment and how its central theme no-self uncannily maps onto the scientific investigation of ego-dissolution states currently undergoing a renaissance within research fields, especially the clinical investigations of mindfulness and psychedelics. It is vital that altered states of consciousness continue to be explored both in a pure sense - to understand how our consciousness and sense of phenomenal self occurs - but also, critically, in an applied sense. After all, one of the main aims of psychiatry is to increase the well-being of our patients by altering their consciousness and how can we hope to do this without exploring the full breadth of phenomenal states available to human beings? The science and clinical application of altered states is clearly nascent and vulnerable to much disagreement, explaining these unusual, mystical states of human consciousness is complex with the exact explanatory theory being still unknown to us.
As seen in the enlightenment vignettes, mystical experiences can be wonderful, profound experiences and also transformative to a person’s being. Contemplative techniques are powerful but in our rush to clinically apply them we must not forget their basis in spirituality where the insight offered is perhaps more profound. Maybe Western clinical science should not be so afraid of the transcendental, mystical or spiritual? This is an area that would require much rehabilitation and careful introduction from the clichés and stereotypes it causes to arise in our modern day minds. Psychedelics serve as warning, as an area of fruitful application unfortunately stuck in a rut for many decades because of cultural and political biases that even now prove hard to overcome. One can’t help but feel that the mystical and spiritual - and I do mean spiritual in a very simple, down to earth manner, as simply the non-judgemental exploration of being – is something that would enrich most people’s lives beneficially. It appears only recently that it has been lost within industrialised civilisation. Mystical experience is something humans have derived great profundity and healing from for an awfully long time, perhaps we should endeavour to re-embrace it?
Armstrong, G., 2017. Emptiness: A Practical Guide for Meditators. Wisdom Publications.
Austin, J., 2011. Meditating Selflessly: Practical Neural Zen. MIT Press.
Baggini, B., 2012. The Ego Trick. Portobello Books.
Blomfield V., 2011, Gautama Buddha: The Life and Teachings of the Awakened One
Carhart-Harris, R, et al., 2014. The entropic brain: A theory of conscious states informed by neuroimaging research with psychedelic drugs. Frontiers in Human Neuroscience, 8(20),
conscioustv. (2018). Adyashanti - 'Awakening' - interview by Renate McNay. [Online Video]. 5 August 2011. Available from: https://www.youtube.com/watch?v=lUTF8n_WJko. [Accessed: 10 November 2018].
Conze, E., 2008. Buddhism: A Short History. Oneworld Publications.
Freud, S., 2002. Civilization and Its Discontents (Penguin Modern Classics). Penguin Classics.
Griffiths, R.R. et al, 2008. Mystical-type experiences occasioned by psilocybin mediate the attribution of personal meaning and spiritual significance 14 months later. Journal of Psychopharmacology, 22(6), 621-632.
Haubner, H., 2013. Zen Confidential: Confessions of a Wayward Monk. SHAMBHALA PUB.
Kabat-Zinn, J., 2013. Full Catastrophe Living. 2nd ed. London: Piatkus.
Kapleau, P., 1989. The Three Pillars of Zen. 1st ed. New York: Anchor Books.
Kornfield, K., 2008. The Wise Heart: Buddhist Psychology for the West. Ebury Press.
Lukoff, D, 1985. The Diagnosis of Mystical Experiences with Psychotic Features. The Journal of Transpersonal Experience, 17:2, 155-181.
Lukoff, D, 2007. Visionary Spiritual Experiences. Southern Medical Journal, 100(6), 635-641.
Metzinger, T., 2004. Being No One: The Self-Model Theory of Subjectivity. MIT Press.
Milliere, R et al., 2018. Psychedelics, Meditation and Self Consciousness. Frontiers in Human Neuroscience,
Pew Research Center. 2018. Mystical Experiences. [ONLINE] Available at: http://www.pewresearch.org/fact-tank/2009/12/29/mystical-experiences/. [Accessed 12 August 2018].
Pollan, M., 2018. How to Change Your Mind. Allen Lane.
Suzuki, S., 2011. Zen Mind, Beginner's Mind. Shambhala Publications, Inc.
Tricycle, Kornfield J.. 2018. Identity and Selflessness in Buddhism - No Self or True Self? [ONLINE] Available at: https://tricycle.org/magazine/no-self-or-true-self/. [Accessed 15 August 2018].
Upton, P., 2012. Psychology Express: Developmental Psychology. 1st ed. London: Pearson Education Ltd.
Walsh, R, 1993. Phenomenological mapping and comparisons of Shamanic, Buddhist, Yogic and Schizophrenic Experiences. Journal of the American Academy of Religion, 61, 739-769.
Warner, B., 2005. Hardcore Zen: Punk Rock, Monster Movies, and the Truth about Reality. Wisdom Publications MA.
Watts, A., 2017. Psychotherapy East & West. New World Library.
Watts, A., 2018. Out of Your Mind. Souvenir Press Ltd.
Watts, A., 1989. The way of Zen. New York : Vintage Books, 1989, c1957.
Wright, R., 2017. Why Buddhism is True: The Science and Philosophy of Meditation and Enlightenment. Simon & Schuster.