Abstract In The Emperor’s New Mind and Shadows of the Mind, Roger Penrose followed a delicate thread to begin to unravel the problem of consciousness. He concluded that conscious thought is more than computation—our minds utilize some type of non-algorithmic processing unavailable in computers. Regarding the identity of the proposed processing, the intrepid sleuth also searched for a ‘subtle and largely unknown physical principle’ capable of performing the needed non-computational actions. That principle was deduced to be ‘objective reduction’ (OR) of quantum coherent superposition, Penrose’s quantum gravity solution for the problem of wave function collapse in quantum mechanics. The next piece of the puzzle then became: where and how could quantum coherent superposition and OR occur in the brain? To that end, Penrose began collaboration with this author, who suggested that the logical and most likely source of macroscopic quantum effects in the brain lies in neuronal microtubules in the cell cytoskeleton.
Abstract In The Emperor’s New Mind and Shadows of the Mind, Roger Penrose followed a delicate thread to begin to unravel the problem of consciousness. He concluded that conscious thought is more than computation—our minds utilize some type of non-algorithmic processing unavailable in computers. Regarding the identity of the proposed processing, the intrepid sleuth also searched for a ‘subtle and largely unknown physical principle’ capable of performing the needed non-computational actions. That principle was deduced to be ‘objective reduction’ (OR) of quantum coherent superposition, Penrose’s quantum gravity solution for the problem of wave function collapse in quantum mechanics. The next piece of the puzzle then became: where and how could quantum coherent superposition and OR occur in the brain? To that end, Penrose began collaboration with this author, who suggested that the logical and most likely source of macroscopic quantum effects in the brain lies in neuronal microtubules in the cell cytoskeleton.
Potential features of quantum computation could explain enigmatic aspects of consciousness. The Penrose—Hameroff model (orchestrated objective reduction: ‘Orch OR’) suggests that quantum superposition and a form of quantum computation occur in microtubules—cylindrical protein lattices of the cell cytoskeleton within the brain's neurons. Microtubules couple to and regulate neural–level synaptic functions, and they may be ideal quantum computers because of dynamical lattice structure, quantum–level subunit states and intermittent isolation from environmental interactions. In addition to its biological setting, the Orch OR proposal differs in an essential way from technologically envisioned quantum computers in which collapse, or reduction to classical output states, is caused by environmental decoherence (hence introducing randomness). In the Orch OR proposal, reduction of microtubule quantum superposition to classical output states occurs by an objective factor: Roger Penrose's quantum gravity threshold stemming from instability in Planck–scale separations (superpositions) in spacetime geometry. Output states following Penrose's objective reduction are neither totally deterministic nor random, but influenced by a non–computable factor ingrained in fundamental spacetime. Taking a modern pan–psychist view in which protoconscious experience and Platonic values are embedded in Planck–scale spin networks, the Orch OR model portrays consciousness as brain activities linked to fundamental ripples in spacetime geometry.
What is consciousness? Conventional approaches see it as an emergent property of complex interactions among individual neurons; however these approaches fail to address enigmatic features of consciousness. Accordingly, some philosophers have contended that "qualia," or an experiential medium from which consciousness is derived, exists as a fundamental component of reality. Whitehead, for example, described the universe as being composed of "occasions of experience." To examine this possibility scientifically, the very nature of physical reality must be re-examined. We must come to terms with the physics of spacetime--as described by Einstein's general theory of relativity, and its relation to the fundamental theory of matter--as described by quantum theory. Roger Penrose has proposed a new physics of objective reduction: "OR," which appeals to a form of quantum gravity to provide a useful description of fundamental processes at the quantum/classical borderline. Within the OR scheme, we consider that consciousness occurs if an appropriately organized system is able to develop and maintain quantum coherent superposition until a specific "objective" criterion (a threshold related to quantum gravity) is reached; the coherent system then self-reduces (objective reduction: OR). We contend that this type of objective self-collapse introduces non-computability, an essential feature of consciousness which distinguishes our minds from classical computers. Each OR is taken as an instantaneous event--the climax of a self-organizing process in fundamental spacetime--and a candidate for a conscious Whitehead "occasion of experience." How could an OR process occur in the brain, be coupled to neural activities, and account for other features of consciousness? We nominate a quantum computational OR process with the requisite characteristics to be occurring in cytoskeletal micro-tubules within the brain's neurons. In this model, quantum-superposed states develop in microtubule subunit proteins ("tubulins") within certain brain neurons, remain coherent, and recruit more superposed tubulins until a mass-time-energy threshold (related to quantum gravity) is reached. At that point, self-collapse, or objective reduction (OR), abruptly occurs. We equate the pre-reduction, coherent superposition ("quantum computing") phase with pre-conscious processes, and each instantaneous (and non-computable) OR, or self-collapse, with a discrete conscious event. Sequences of OR events give rise to a "stream" of consciousness. Microtubule-associated proteins can "tune" the quantum oscillations of the coherent superposed states; the OR is thus self-organized, or "orchestrated" ("Orch OR"). Each Orch OR event selects (non-computably) microtubule subunit states which regulate synaptic/neural functions using classical signaling. The quantum gravity threshold for self-collapse is relevant to consciousness, according to our arguments, because macroscopic superposed quantum states each have their own spacetime geometries. These geometries are also superposed, and in some way "separated," but when sufficiently separated, the superposition of spacetime geometries becomes significantly unstable and reduces to a single universe state. Quantum gravity determines the limits of the instability; we contend that the actual choice of state made by Nature is non-computable. Thus each Orch OR event is a self-selection of spacetime geometry, coupled to the brain through microtubules and other biomolecules. If conscious experience is intimately connected with the very physics underlying spacetime structure, then Orch OR in microtubules indeed provides us with a completely new and uniquely promising perspective on the difficult problems of consciousness.
Features of consciousness difficult to understand in terms of conventional neuroscience have evoked application of quantum theory, which describes the fundamental behavior of matter and energy. In this paper we propose that aspects of quantum theory (e.g. quantum coherence) and of a newly proposed physical phenomenon of quantum wave function self-collapse(objective reduction: OR -Penrose, 1994) are essential for consciousness, and occur in cytoskeletal microtubules and other structures within each of the brain's neurons. The particular characteristics of microtubules suitable for quantum effects include their crystal-like lattice structure, hollow inner core, organization of cell function and capacity for information processing. We envisage that conformational states of microtubule subunits (tubulins) are coupled to internal quantum events, and cooperatively interact (compute) with other tubulins. We further assume that macroscopic coherent superposition of quantum-coupled tubulin conformational states occurs throughout significant brain volumes and provides the global binding essential to consciousness. We equate the emergence of the microtubule quantum coherence with pre-conscious processing which grows (for up to 500 milliseconds) until the mass-energy difference among the separated states of tubulins reaches a threshold related to quantum gravity. According to the arguments for OR put forth in Penrose (1994), superpositioned states each have their own space-time geometries. When the degree of coherent mass-energy difference leads to sufficient separation of space-time geometry, the system must choose and decay (reduce, collapse) to a single universe state. In this way, a transient superposition of slightly differing space-time geometries persists until an abrupt quantum classical reduction occurs. Unlike the random, subjective reduction(SR, or R) of standard quantum theory caused by observation or environmental entanglement, the OR we propose in microtubules is a self-collapse and it results in particular patterns of microtubule-tubulin conformational states that regulate neuronal activities including synaptic functions. Possibilities and probabilities for post-reduction tubulin states are influenced by factors including attachments of microtubule-associated proteins (MAPs) acting as nodeswhich tune and orchestratethe quantum oscillations. We thus term the self-tuning OR process in microtubules orchestrated objective reduction(B>Orch OR, and calculate an estimate for the number of tubulins (and neurons) whose coherence for relevant time periods (e.g. 500 milliseconds) will elicit Orch OR. In providing a connection among 1) pre-conscious to conscious transition, 2) fundamental space-time notions, 3) non-computability, and 4) binding of various (time scale and spatial) reductions into an instantaneous event (conscious now, we believe Orch OR in brain microtubules is the most specific and plausible model for consciousness yet proposed.
Abstract In neuroscience, the flow of time is a conscious experience produced by the brain. But in physics, time is either a process, or a dimension in four-dimensional spacetime geometry. Could all three explanations be correct? The Penrose–Hameroff ‘Orch OR’ theory suggests consciousness is a sequence of discrete, irreversible quantum state reductions occurring at an objective threshold (‘objective reduction’, ‘OR’) a process in fundamental spacetime geometry. These ‘self-collapses’ of the quantum wavefunction are ‘orchestrated’ in microtubules inside brain neurons. Each Orch OR event selects microtubule states which purposefully regulate neuronal functions, and provide sequences of ‘NOW’ moments of conscious experience. Connected to fundamental spacetime geometry by Penrose ‘OR’, consciousness is quantum state reduction, a set of irreversible steps which ‘ratchet forward’ in the fine scale geometry of the universe, creating a flow of time.
FINDING: The dominant research thread is the **Orch-OR (Penrose-Hameroff) hypothesis** — quantum coherence in microtubules as the physical basis of consciousness — with new experimental claims of quantum effects in brain tissue, plus Chris Fields' critique of the measurement problem in cellular intelligence. | MATH: Orch-OR invokes **objective reduction (OR)** — a gravity-induced wavefunction collapse threshold: EΔ≈ℏ/T (energy-time uncertainty for self-collapse), with proposed tubulin dipole states as qubits in a **lattice of ~10^8 tubulins per neuron**, coherence times ~10^-4 to 10^-3 s. Penrose's gravitational self-energy: EG=4πG1∫(∇ϕ1−∇ϕ2)2d3x — collapse when EG⋅T≈ℏ. No new constants; relies on ℏ,G,c. | CONNECTION: Microtubules are **hexagonal lattices** (13 protofilaments, 8 nm tubulin dimers) — a **crystallographic symmetry (p6m)**. The tubulin dimer spacing ratio Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence.com
From the Publisher:
A New York Times bestseller when it appeared in 1989, Roger Penrose's The Emperor's New Mind was universally hailed as a marvelous survey of modern physics as well as a brilliant reflection on the human mind, offering a new perspective on the scientific landscape and a visionary glimpse of the possible future of science. Now, in Shadows of the Mind, Penrose offers another exhilarating look at modern science as he mounts an even more powerful attack on artificial intelligence. But perhaps more important, in this volume he points the way to a new science, one that may eventually explain the physical basis of the human mind. Penrose contends that some aspects of the human mind lie beyond computation. This is not a religious argument (that the mind is other than physical) nor is it based on the brain's vast complexity (the weather is immensely complex, says Penrose, but it is still a computable thing, at least in theory). Instead, he provides powerful arguments to support his conclusion that there is in the conscious activity of the brain that transcends computation - and will find no explanation in terms of present-day science. To illuminate what he believes this something might be, and to suggest where a new physics must proceed so that we may understand it, Penrose cuts a wide swathe through modern science, providing penetrating looks at everything from Turing computability and Godel's incompleteness, via Schrodinger's Cat and the Elitzur-Vaidman bomb-testing problem, to detailed microbiology. Of particular interest is Penrose's extensive examination of quantum mechanics, which introduces some new ideas that differ markedly from those advanced in The Emperor's New Mind, especially concerning the mysterious interface where classical and quantum physics meet. But perhaps the most interesting wrinkle in Shadows of the Mind is Penrose's excursion into microbiology, where he examines cytoskeletons and microtubules, minute substructures lying dee