“Conscious ‘free will’ is problematic because (1) brain mechanisms causing consciousness are unknown, (2) measurable brain activity correlating with conscious perception apparently occurs too late for real-time conscious response, consciousness thus being considered ‘epiphenomenal illusion,’ and (3) determinism, i.e., our actions and the world around us seem algorithmic and inevitable. the penrose-hameroff theory of ‘orchestrated objective reduction (orch or)’ identifies discrete conscious moments with quantum computations in microtubules inside brain neurons, e.g., 40/s in concert with gamma synchrony eeg. microtubules organize neuronal interiors and regulate synapses. in orch or, microtubule quantum computations occur in integration phases in dendrites and cell bodies of integrate-and-fire brain neurons connected and synchronized by gap junctions, allowing entanglement of microtubules among many neurons. quantum computations in entangled microtubules terminate by penrose ‘objective reduction (or),’ a proposal for quantum state reduction and conscious moments linked to fundamental spacetime geometry. each or reduction selects microtubule states which can trigger axonal firings, and control behavior. the quantum computations are ‘orchestrated’ by synaptic inputs and memory (thus ‘orch or’). if correct, orch or can account for conscious causal agency, resolving problem 1. regarding problem 2, orch or can cause temporal non-locality, sending quantum information backward in classical time, enabling conscious control of behavior. three lines of evidence for brain backward time effects are presented. regarding problem 3, penrose or (and orch or) invokes non-computable influences from information embedded in spacetime geometry, potentially avoiding algorithmic determinism. in summary, orch or can account for real-time conscious causal agency, avoiding the need for consciousness to be seen as epiphenomenal illusion. orch or can rescue conscious free will.”
Hameroff, S. R.. (2007). The brain is both neurocomputer and quantum computer. Cognitive Science, 31(6), 1035–1045.
“In their article, is the brain a quantum computer,? litt, eliasmith, kroon, weinstein, and thagard (2006) criticize the penrose-hameroff ‘orch or’ quantum computational model of consciousness, arguing instead for neurocomputation as an explanation for mental phenomena. here i clarify and defend orch or, show how orch or and neurocomputation are compatible, and question whether neurocomputation alone can physiologically account for coherent gamma synchrony eeg, a candidate for the neural correlate of consciousness. orch or is based on quantum computation in microtubules within dendrites in cortex and other regions linked by dendritic-dendritic gap junctions (‘dendritic webs’) acting as laterally connected input layers of the brain’s neurocomputational architecture. within dendritic webs, consciousness is proposed to occur as gamma eeg-synchronized sequences of discrete quantum computational events acting in integration phases of neurocomputational ‘integrate-and-fire’ cycles. orch or is a viable approach toward understanding how the brain produces consciousness.”
Hameroff, S., & Penrose, R.. (2014). Consciousness in the universe: A review of the “Orch OR” theory. Physics of Life Reviews
“The critical commentary by reimers et al.  regarding the penrose–hameroff theory of ‘orchestrated objective reduction’ (‘orch or’) is largely uninformed and basically incorrect, as they solely criticize non-existent features of orch or, and ignore (1) actual orch or features, (2) supportive evidence, and (3) previous answers to their objections (section 5.6 in our review ). here we respond point-by-point to the issues they raise.”
Hameroff, S., & Penrose, R.. (2014). Reply to seven commentaries on “Consciousness in the universe: Review of the ‘Orch OR’ theory”. Physics of Life Reviews, 11(1), 94–100.
“The nature of consciousness, the mechanism by which it occurs in the brain, and its ultimate place in the universe are un-known. 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, neu-roscience, 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.”
Hameroff, S., & Penrose, R.. (2014). Consciousness in the universe: A review of the “Orch OR” theory. Physics of Life Reviews, 11(1), 39–78.
“What is consciousness? 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 comprised of ‘occasions of experience.’ to examine this possibility scientifically, the very nature of physical reality must be reexamined. we must come to terms with the physics of space-time-as is described by einstein’s general theory of relativity-and its relation to the fundamental theory of matter-as described by quantum theory. this leads us to employ 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 (penrose, 1994; 1996). 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. or is taken as an instantaneous event-the climax of a self-organizing process in fundamental space-time-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 an or process with the requisite characteristics to be occurring in cytoskeletal microtubules within the brain’s neurons (penrose and hameroff, 1995; hameroff and penrose, 1995; 1996). in this model, quantum-superposed states develop in microtubule subunit proteins (‘tubulins’), 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 select…”