Some memories pull you back again and again. It’s like being drawn to
certain pictures on a wall, down a corridor that represents life’s
In one such picture, I was 10. My grandmother had taken my younger
sister and me on a ferry journey across the harbour from Circular Quay
in the busy commercial hub of Sydney, to Manly on the north side. Manly
was a fun place for a young boy. There were fun rides, visits to what
was then called the Manly Aquarium with its display of menacing-looking
sharks, stingrays and turtles, the surf beach a short walk away and the
busy activity of ferries, boats, swimmers and tourists on the harbour.
Leaning over a stone breakwater near Manly’s ferry terminal, I looked
down onto the shimmering, opaque surface of Sydney Harbour, and wondered
what mysteries lay hidden underneath. I knew there was another world
down there out of sight and mind to most terrestrials.
A desire to know what lies hidden beneath our normal superficial view of
things has prevailed throughout my life. As a boy I was always the young
scientist, day-dreaming about owning a laboratory, doing important
experiments and making discoveries. But I never became a scientist.
Instead I pursued a career in clinical dentistry, following in the
footsteps of my father and his father before him.
I did, however, plunge into the mysterious depths of the ocean as a
dedicated diver. I learned to scuba dive in 1974, and pursued it with
enthusiasm. My friends and I would – in the early years of diving –
plunge ourselves off ocean rock platforms to enter and exit our ocean
playground. Often, as an exercise – without scuba cylinders and
wearing only protective wetsuits, fins and gloves – we would jump off
the rocks into the heaving ocean and then allow the waves to deposit us
back onto the rock platform. We would even hold hands and do this in
unison. Bad timing or a bad choice of wave gave us some bruises, but it
was all fun and all part of gaining confidence in the sea.
Before long I was taking a camera to record what I saw while diving and
learn more about the creatures I came across. I soon acquired a taste
for the adventure and discovery associated with undersea exploration,
and sharing these discoveries with others through my photography became
a lifelong passion and a parallel vocation with my professional life as
a dental surgeon.
I would eventually see these photographs published in respected journals
like those of the National Geographic and Australian Geographic
societies. Photographic assignments and sponsored diving projects
(mainly through the support of the Australian Geographic Society) gave
my diving career extra focus and the ability to engage friends in
teamwork towards a satisfying goal.
As my familiarity and confidence in the ocean grew with experience, I
was soon introduced to shipwreck diving, which usually meant diving to
greater depths. At first, we would explore scuttled hulks or genuine
wrecks using compressed air breathed from a single scuba tank. Then, as
we descended further – to explore even deeper wrecks – we wore two
tanks for the extra air we needed at depth, and also to allow time for
the inevitable decompression stops needed to avoid the bends.
I would soon extend my skills to freshwater cave-diving, for which
special training and certification was required. Flooded caves are
usually pitch black with absolutely no penetration of sunlight, and the
entrance is often the only safe exit. Getting lost in such an
environment with a limited air supply is not an option. Cave-diving is
definitely not for the claustrophobic! However, this foreboding
underground world can delight the explorer with mineral sculptures that
have taken Earth hundreds of thousands of years to shape. It’s also a
world that can re-set a diver’s appreciation of the passage of time
from a human scale to a much vaster one.
The ocean, however, was where I spent most of my time underwater. Around
the mid-1990s, my wreck-diving friends and I undertook training in the
use of specially mixed breathing gases – helium, oxygen and air – to
more safely manage deeper plunges into the ocean. Mistakes in blending
or not carefully checking the gas in our breathing mixture could be
fatal, and it resulted in the deaths of some friends and acquaintances.
As the years and decades passed, I continued to precariously balance the
high demands of my dental career and my passion for ocean exploration
and underwater photography. But – as busy as I was with these pursuits
– I found time for another discipline.
A few years after I graduated from university, I read an article in
Reader’s Digest about a meditation technique known as Transcendental
Meditation (TM). I read that it had been introduced to the western world
by an Indian scholar by the name of Maharishi Mahesh Yogi. I was aware
that this man had been involved with The Beatles. I was intrigued by the
evidence-based claims of improved self-actualisation, improved health
and sense of wellbeing, greater stamina and clarity of mind.
I had been brought up a Catholic and had no wish to embrace another
religion, but the article stated that Transcendental Meditation was not
a religion and that it did not matter whether one was religious or
non-religious – it was a secular technique for the natural resting of
the mind to achieve a highly beneficial state of consciousness that came
with a whole bunch of health benefits. I was intrigued.
After talking to a doctor friend of mine who practised TM, I was assured
of the wisdom of learning this life skill and started in 1981. I have
virtually not stopped since!
I recall once stopping my meditation practice for a number of months,
perhaps a year after I learned the technique. It was my own experiment
to see if it really was giving me benefits. I was reassured by this test
and took it up again, disciplining myself to practise the technique
twice a day for 20 minutes each time.
The TM teachers provided some basic knowledge to help new meditators
understand what was going on when she or he ‘transcended’ –
meaning to ‘go beyond’ or ‘pass through the superficial levels of
familiar wakeful consciousness’. They would speak of an ‘ocean’ or
‘pond’ of consciousness with all our busy mental activity happening
at the top, just like busy ocean waves on the surface of the ocean
depths. Thoughts, they said, were like incipient bubbles arising from
the depths of this ocean, getting bigger as they reached the surface.
Transcendence was the reversal of this process –moving deeper and
deeper into the silent realms of the mind, where the bubbles of thought
become less dominating. Often while ‘diving’ into the silent depths
of my own awareness, I find myself attached to a thought again and
brought to the surface. TM meditators are taught to then go back to
repeating a non-sensible word that acts as a vehicle for the mind to
dive back into the depths.
It was a silent, peaceful world down there in the depths of my
consciousness. It reminded me of a similar silence and peace I
encountered while scuba diving or free-diving. When diving into the
watery ocean, I became very present – ‘in the moment’ – just as
I did while meditating. It didn’t seem to matter if I was burdened
with problems on the surface. They all became irrelevant as soon as I
plunged underwater. I also experienced silence, freedom, unboundedness
and even a sense of unity – a sense of greater ‘being’ that
transcended my small self. It’s a sense of belonging to something
The correlation captured my interest. One diving medium – the ocean
– was very physical, the other more nebulous and abstract. Could the
two possibly be related?
This book has resulted from my research into that correlation. The
curiosity I expressed as a young boy for what lies under the surface of
Sydney Harbour culminated in my becoming an underwater explorer. Little
did I know then that those acquired skills in ocean exploration plus my
acquisition of an effective meditation technique would equip me in
dealing with my later curiosity for what lies beneath the superficial
sensory-dependant levels of conscious awareness.
 The story of McCavity – ‘Mysterious McCavity’ – was told in
Australian Geographic, Issue 45, Jan–March 1997
 Alan Nichols, J.D., D.S., FN’84; The Explorers Log, Spring 2014,
Vol 46. No. 2.
Excerpted from "Ocean of Self: An ocean diver explores the nature of consciousness" by Mark N. Spencer. Copyright © 2017 by Mark N. Spencer. Excerpted by permission. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher. Excerpts are provided solely for the personal use of visitors to this web site.