We conclude that consciousness plays an intrinsic role in the universe.
The nature of consciousness, the mechanism by which it occurs in the brain, and its ultimate place in the universe are unknown. We proposed in the mid 1990's that consciousness depends on biologically ‘orchestrated’ coherent quantum processes in collections of microtubules within brain neurons, that these quantum processes correlate with, and regulate, neuronal synaptic and membrane activity, and that the continuous Schrödinger evolution of each such process terminates in accordance with the specific Diósi–Penrose (DP) scheme of ‘objective reduction’ (‘OR’) of the quantum state. This orchestrated OR activity (‘Orch OR’) is taken to result in moments of conscious awareness and/or choice. The DP form of OR is related to the fundamentals of quantum mechanics and space–time geometry, so Orch OR suggests that there is a connection between the brain's biomolecular processes and the basic structure of the universe. Here we review Orch OR in light of criticisms and developments in quantum biology, neuroscience, physics and cosmology. We also introduce a novel suggestion of ‘beat frequencies’ of faster microtubule vibrations as a possible source of the observed electro-encephalographic (‘EEG’) correlates of consciousness. We conclude that consciousness plays an intrinsic role in the universe.
1. Introduction: Consciousness in the universe
Consciousness implies awareness: subjective, phenomenal experience of internal and external worlds. Consciousness also implies a sense of self, feelings, choice, control of voluntary behavior, memory, thought, language, and (e.g. when we close our eyes, or meditate) internally-generated images and geometric patterns. But what consciousness actually is remains unknown. Our views of reality, of the universe, of ourselves depend on consciousness. Consciousness defines our existence.
Three general possibilities regarding the origin and place of consciousness in the universe have been commonly expressed.
Consciousness is not an independent quality but arose, in terms of conventional physical processes, as a natural evolutionary consequence of the biological adaptation of brains and nervous systems. This prevalent scientific view is that consciousness emerged as a property of complex biological computation during the course of evolution. Opinions vary as to when, where and how consciousness appeared, e.g. only recently in humans, or earlier in lower organisms. Consciousness as an evolutionary adaptation is commonly assumed to be epiphenomenal (i.e. a secondary effect without independent influence ,  and ), and also illusory (largely constructing reality, rather than perceiving it ). Nonetheless, consciousness is frequently argued to confer beneficial advantages to species . Overall, in this view, consciousness is not an intrinsic feature of the universe.
Consciousness is a separate quality, distinct from physical actions and not controlled by physical laws, that has always been in the universe. Descartes' ‘dualism’, religious viewpoints, and other spiritual approaches assume consciousness has been in the universe all along, e.g. as the ‘ground of being’, ‘creator’ or component of an omnipresent ‘God’ . In this view consciousness can causally influence physical matter and human behavior, but has no basis or description in science . In another approach, panpsychism attributes consciousness to all matter, but without scientific identity or causal influence. Idealism contends consciousness is all that exists, the material world (and science) being an illusion . In all these views, consciousness lies outside science.
Consciousness results from discrete physical events; such events have always existed in the universe as non-cognitive, proto-conscious events, these acting as part of precise physical laws not yet fully understood. Biology evolved a mechanism to orchestrate such events and to couple them to neuronal activity, resulting in meaningful, cognitive, conscious moments and thence also to causal control of behavior. These events are proposed specifically to be moments of quantum state reduction (intrinsic quantum “self-measurement”). Such events need not necessarily be taken as part of current theories of the laws of the universe, but should ultimately be scientifically describable. This is basically the type of view put forward, in very general terms, by the philosopher A.N. Whitehead  and  and also fleshed out in a scientific framework in the Penrose–Hameroff theory of ‘orchestrated objective reduction’ (‘Orch OR’ , , , ,  and ). In the Orch OR theory, these conscious events are terminations of quantum computations in brain microtubules reducing by Diósi–Penrose ‘objective reduction’ (‘OR’), and having experiential qualities. In this view consciousness is an intrinsic feature of the action of the universe.
In summary, we have:(A)
Science/Materialism, with consciousness having no distinctive role , , ,  and .
Dualism/Spirituality, with consciousness (etc.) being outside science ,  and .
Science, with consciousness as an essential ingredient of physical laws not yet fully understood , , , , , , ,  and .
2. Consciousness, computation and brain activities
2.1. Unexplained features of consciousness
How does the brain produce consciousness? Most scientists and philosophers view consciousness as an emergent property of complex computation among ‘integrate-and-fire’ brain neurons which interconnect and switch at chemically-mediated synapses. However the mechanism by which such neuronal computation may produce conscious experience remains unknown  and . Specific unexplained features of consciousness include the following:
The ‘hard problem’ What is the nature of phenomenal experience, and what distinguishes conscious from non-conscious cognition? Perception and behavior may be accompanied or driven by phenomenal conscious awareness, experience, or subjective feelings, composed of what philosophers call ‘qualia’ . However perception and behavior may at other times be unaccompanied by consciousness. We could have evolved as full-time non-conscious ‘zombies’ performing complex ‘auto-pilot’ behaviors without conscious awareness. How and why do we have phenomenal consciousness, an ‘inner life’ of subjective experience?
‘Binding’ Disparate sensory inputs are processed in different brain regions, at slightly different times, and yet are bound together into unified conscious content (‘binding’ ). How is conscious content bound together?
Synchrony Neuronal membrane polarization states may be precisely synchronized over large regions of brain , and also propagate through brain regions as synchronized zones . Does precise synchrony require electrical synapses (‘gap junctions’) and/or quantum entanglement? Does synchrony reflect discrete, unified conscious moments?
‘Non-computability’ and causal agency As shown by Gödel's theorem, Penrose and  described how the mental quality of ‘understanding’ cannot be encapsulated by any computational system and must derive from some ‘non-computable’ effect. Moreover, the neurocomputational approach to volition, where algorithmic computation completely determines all thought processes, appears to preclude any possibility for independent causal agency, or free will. Something else is needed. What non-computable factor may occur in the brain?
Cognitive behaviors of single cell organisms Protozoans like Physarum can escape mazes and solve problems, and Paramecium can swim, find food and mates, learn, remember and have sex, all without synaptic connections  and . How do single cells manifest intelligent behavior?
2.2. Conscious moments and computation
Consciousness has often been argued to be a sequence of discrete moments. William James  described the “specious present, the short duration of which we are immediately and incessantly sensible” (though James was vague about duration, and also described a continual ‘stream of consciousness’). The “perceptual moment” theory of Stroud  described consciousness as a series of discrete events, like sequential frames of a movie (modern film and video present 24 to 72 frames per second, 24 to 72 Hertz, ‘Hz’). Consciousness is also seen as sequences of discrete events in Buddhism, trained meditators describing distinct “flickerings” in their experience of pure undifferentiated awareness . Buddhist texts portray consciousness as “momentary collections of mental phenomena”, and as “distinct, unconnected and impermanent moments that perish as soon as they arise”. Buddhist writings even quantify the frequency of conscious moments. For example the Sarvaastivaadins  described 6,480,000 “moments” in 24 hours (an average of one “moment” per 13.3 ms, 75 Hz), and some Chinese Buddhists as one “thought” per 20 ms (50 Hz). The best measurable correlate of consciousness through modern science is gamma synchrony electro-encephalography (EEG), 30 to 90 Hz coherent neuronal membrane activities occurring across various synchronized brain regions. Slower periods, e.g. 4 to 7 Hz theta frequency, with nested gamma waves could correspond to saccades and visual gestalts  and  (Fig. 11). Thus, we may argue that consciousness consists of discrete events at varying frequencies occurring across brain regions, for example 40 conscious moments per second, synchronized among neurons in frontal and parietal cortex. What are these conscious moments?
The over-arching presumption in modern science and philosophy is that consciousness emerges from complex synaptic computation in networks of brain neurons acting as fundamental information units. In digital computers, discrete voltage levels represent information units (e.g. ‘bits’) in silicon logic gates. McCulloch and Pitts  proposed such gates as integrate-and-fire artificial neurons, leading to ‘perceptrons’  and other types of ‘artificial neural networks’ capable of learning and self-organized behavior. Similarly, according to the standard ‘Hodgkin–Huxley’  model, biological neurons are ‘integrate-and-fire’ threshold logic devices in which multiple branched dendrites and a cell body (soma) receive and integrate synaptic inputs as membrane potentials (Fig. 1). According to Hodgkin and Huxley, the integrated potential is then compared to a threshold potential at the axon hillock, or axon initiation segment (AIS). When AIS threshold is reached by the integrated potential (Fig. 2), an all-or-none action potential ‘firing’, or ‘spike’ is triggered as output, conveyed along the axon to the next synapse. Cognitive networks of Hodgkin–Huxley neurons connected by variable strength synapses  can self-organize and learn, their axonal firing outputs controlling downstream activity and behavior.
Neither the specific neuronal activities contributing to complexity, nor any predicted complexity threshold for emergence of consciousness have been put forth. Nor is there a sense of how complexity per se could give rise to discrete conscious moments.
The non-computable ingredient required for human consciousness and understanding, Penrose suggested, would have to lie in an area where our current physical theories are fundamentally incomplete, though of important relevance to the scales that are pertinent to the operation of our brains. The only serious possibility was the incompleteness of quantum theory—an incompleteness that both Einstein and Schrödinger (and also Dirac) had recognized, despite quantum theory having frequently been argued to represent the pinnacle of 20th century scientific achievement.
The Orch OR proposal suggests conscious experience is intrinsically connected to the fine-scale structure of space–time geometry, and that consciousness could be deeply related to the operation of the laws of the universe.