Entheogens: Review of Thomas Roberts’ Psychoactive Sacramentals
David W. Salt
James McClenon, Wondrous Healing: Shamanism, Human Evolution, and the
Origin of Religion
Helen Oppenheimer, Making Good: Creation, Tragedy and Hope
From Matter To Mind
Abstract: The relation between mind and matter is considered in terms of
recent ideas from both phenomenology and brain science. Phenomenology is
used to give clues to help bridge the brain–mind gap by providing constraints
on any underlying neural architecture suggested from brain science. A tentative
reduction of mind to matter is suggested and used to explain various features
of phenomenological experience and of ownership of conscious experience.
The crucial mechanism is the extended duration of the corollary discharge
of attention movement, with its gating of activity for related content.
Aspects of experience considered in terms of the model are the discontinuous
nature of consciousness, immunity to error through misidentification, and
the state of ‘pure’ consciousness as experienced through meditation. Corollary
discharge of attention movement is proposed as the key idea bringing together
basic features of meditation, consciousness and neuroscience, and helping
to bridge the gap between mind and matter.
Correspondence: J.G. Taylor, Department of Mathematics, King’s College,
Strand, London WC2R2LS, UK. Email: email@example.com
Synchronous Firing and Its Influence on the Brain’s Electromagnetic Field
Evidence for an Electromagnetic Field Theory of Consciousness
Abstract: The human brain consists of approximately 100 billion electrically
active neurones that generate an endogenous electromagnetic (em) field,
whose role in neuronal computing has not been fully examined. The source,
magnitude and likely influence of the brain’s endogenous em field are here
considered. An estimate of the strength and magnitude of the brain’s em
field is gained from theoretical considerations, brain scanning and microelectrode
data. An estimate of the likely influence of the brain’s em field is gained
from theoretical principles and considerations of the experimental effects
of external em fields on neurone firing both in vitro and in vivo. Synchronous
firing of distributed neurones phase-locks induced em field fluctuations
to increase their magnitude and influence. Synchronous firing has previously
been demonstrated to correlate with awareness and perception, indicating
that perturbations to the brain’s em field also correlate with awareness.
The brain’s em field represents an integrated electromagnetic field representation
of distributed neuronal information and has dynamics that closely map to
those expected for a correlate of consciousness. I propose that the brain’s
em information field is the physical substrate of conscious awareness —
the cemi field — and make a number of predictions that follow from this
proposal. Experimental evidence pertinent to these predictions is examined
and shown to be entirely consistent with the cemi field theory. This theory
provides solutions to many of the intractable problems of consciousness
— such as the binding problem — and provides new insights into the role
of consciousness, the meaning of free will and the nature of qualia. It
thus places consciousness within a secure physical framework and provides
a route towards constructing an artificial consciousness.
Correspondence: Johnjoe McFadden, School of Biomedical and Life Sciences,
University of Surrey, Guildford, Surrey, GU2 5XH, UK. Email: firstname.lastname@example.org
Difficulties with the Electromagnetic Field Theory of Consciousness
Abstract: The author’s version of the electromagnetic field theory of consciousness
is stated briefly and then three difficulties with the theory are discussed.
The first is a purely technical problem: how to measure accurately enough
the spatial properties of the fields which are proposed to be conscious
and then how to generate these artificially, so that the theory can be
tested. The second difficulty might also be merely technical, or it might
be substantive and fatal to the theory. This is that present measurements
seem to show a non-constant relationship between brain-generated electromagnetic
fields and sensation. The third difficulty involves the basic question
of whether consciousness per se has any direct effect on the brain. As
an afterword, the disproportionate contribution of synchronously firing
neurons to conscious percepts is simply explained in terms of the electromagnetic
field theory of consciousness.
Correspondence: Susan Pockett, Department of Physics, University of
Auckland, Private Bag 92019, Auckland, New Zealand. Email: email@example.com
Christopher Frith and Shaun Gallagher
Models of the Pathological Mind
Christopher Frith is a research professor at the Functional Imaging Laboratory
of the Wellcome Department of Imaging Neuroscience at University College,
London. He explores, experimentally, using the techniques of functional
brain imaging, the relationship between human consciousness and the brain.
His research focuses on questions pertaining to perception, attention,
control of action, free will, and awareness of our own mental states and
those of others. As the following discussion makes clear, Frith investigates
brain systems involved in the choice of one action over another and in
the understanding of other people. Such investigations are aimed at understanding
brain basis of autism and schizophrenia.
In his widely cited study of schizophrenia, The Cognitive Neuropsychology
of Schizophrenia (1992), Frith argues that many of the positive symptoms
of schizophrenia, such as delusions of control, auditory hallucinations,
and thought insertion, involve problems of self-monitoring. Patients, in
effect, lose track of their own intentions and mistakenly attribute agency
for their own actions to someone else. Frith employs models of motor control,
involving comparator mechanisms and efference copy, not only to explain
delusions that involve movement, but also to develop a neurocognitive explanation
of delusional cognition.
One of the central aspects of motor control involves a forward
model, a non- conscious pre-motor system operating prior to the actual
execution of movement and its sensory feedback. This forward mechanism,
Frith argues, generates a conscious sense of agency for action. This is
consistent with research that correlates initial awareness of action with
recordings of the lateralized readiness potential and with transcranial
magnetic stimulation of the supplementary motor area. One’s initial awareness
of a spontaneous voluntary action depends on this forward mechanism. Schizophrenics,
however, have problems with this forward monitoring of movement. They have
problems monitoring their own motor intentions at this level (Malenka et
al., 1982; Frith and Done, 1988).
Following Feinberg (1978), Frith postulates a similar mechanism for
cognition — specifically, for thought and inner speech. He pursues an explanation
of thought insertion, for example, by developing the following line of
Thinking, like all our actions, is normally accompanied by a sense
of effort and deliberate choice as we move from one thought to the next.
If we found ourselves thinking without any awareness of the sense of effort
that reflects central monitoring, we might well experience these thoughts
as alien and, thus, being inserted into our minds (Frith, 1992, p. 81).
The philosopher John Campbell has maintained that Frith’s model
of schizophrenia as a disruption of basic self-monitoring processes provides
the most parsimonious explanation of how self-ascriptions of thoughts are
subject to errors of identification (Campbell, 1999). Frith, as we see
in the following discussion, continues to explore a variety of related
issues: concepts of free will, self- awareness, and theory of mind.
Correspondence: Christopher Frith, Wellcome Dept. of Cognitive Neurology,
Institute of Neurology, Queen Square, London WC1N 3BG. Email: firstname.lastname@example.org
Shaun Gallagher, Department of Philosophy, Canisius College, Buffalo,
NY 14208, USA.