Timing & Time Perception
November 6, 2023
Stuart Hameroff
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...
Cognitive Neuroscience
2021
Stuart Hameroff
The 'Orch OR' theory attributes consciousness to quantum computations in microtubules inside brain neurons. Quantum computers process information as superpositions of multiple possibilities (quantum bits or qubits) which, in Orch OR, are alternative collective dipole oscillations orchestrated ('Orch') by microtubules. These orchestrated oscillations entangle, compute, and terminate ('collapse...
Journal of Integrative Neuroscience
June 1, 2014
Stuart Hameroff, Travis J A Craddock, Jack A Tuszynski
This paper presents a historical perspective on the development and application of quantum physics methodology beyond physics, especially in biology and in the area of consciousness studies. Quantum physics provides a conceptual framework for the structural aspects of biological systems and processes via quantum chemistry. In recent years individual biological phenomena such as photosynthesis...
March 1, 2014
Stuart Hameroff, Roger Penrose
384 citations
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,...
Topics in Cognitive Science
2014
Stuart Hameroff
Cognitive decisions are best described by quantum mathematics. Do quantum information devices operate in the brain? What would they look like? Fuss and Navarro () describe quantum lattice registers in which quantum superpositioned pathways interact (compute/integrate) as 'quantum walks' akin to Feynman's path integral in a lattice (e.g. the 'Feynman quantum chessboard'). Simultaneous alternate...
Frontiers in Integrative Neuroscience
2012
Stuart Hameroff
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...
Computational Intelligence and Neuroscience
2011
Marc Ebner, Stuart R. Hameroff
14 citations
Cognitive brain functions, for example, sensory perception, motor control and learning, are understood as computation by axonal-dendritic chemical synapses in networks of integrate-and-fire neurons. Cognitive brain functions may occur either consciously or nonconsciously (on "autopilot"). Conscious cognition is marked by gamma synchrony EEG, mediated largely by dendritic-dendritic gap...
The Journal of near-death studies
2011
Stuart R. Hameroff
In this article, I reply to Gerald Woerlee's (2011, this issue) claim that during Pam Reynold's near-death experience (NDE), she actually could hear through normal means. I respond in terms of my 35 years experience as a clinical anesthesiologist, researcher into mechanisms of anesthesia and consciousness, and proponent of a theory of non-local consciousness put forth by mathematical physicist...
Journal of Biological Physics
April 1, 2009
Stuart R. Hameroff
111 citations
Cognitive brain functions including sensory processing and control of behavior are understood as "neurocomputation" in axonal-dendritic synaptic networks of "integrate-and-fire" neurons. Cognitive neurocomputation with consciousness is accompanied by 30- to 90-Hz gamma synchrony electroencephalography (EEG), and non-conscious neurocomputation is not. Gamma synchrony EEG derives largely from...
Cognitive Science
November 12, 2007
Stuart Hameroff
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...
NeuroQuantology
September 11, 2007
Stuart R. Hameroff
48 citations
Orch OR (“Orchestrated Objective Reduction”) is a theory of consciousness put forth in the mid-1990s by British physicist Sir Roger Penrose and American anesthesiologist Stuart Hameroff. Whereas most theories assume consciousness emerges from complex computation at the level of synapses among brain neurons, Orch OR involves a specific form of quantum computation which underlies these neuronal...
NeuroQuantology
September 3, 2007
Stuart R. Hameroff, Roger Penrose
202 citations
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 To examine this possibility scientifically, the very nature of physical reality must be re-examined. We must come to terms with the...
Anesthesiology
July 25, 2006
Stuart R. Hameroff
130 citations
THE mechanism by which general anesthetics prevent consciousness remains unknown largely because the mechanism by which brain physiology produces consciousness is unexplained. But the two mysteries seem to share a critical feature—both consciousness and actions of anesthetic gases are mediated through extremely weak London forces (a type of van der Waals force) acting in hydrophobic pockets...
Trends in Cognitive Sciences
November 1, 2001
Nancy J. Woolf, Stuart Hameroff
A theoretical approach relying on quantum computation in microtubules within neurons can potentially resolve the enigmatic features of visual consciousness, but raises other questions. For example, how can delicate quantum states, which in the technological realm demand extreme cold and isolation to avoid environmental 'decoherence', manage to survive in the warm, wet brain? And if such states...
Advances in Consciousness Research
April 12, 2001
Stuart Hameroff
Quantum approaches have enormous explanatory power for understanding enigmatic features of consciousness. The Penrose-Hameroff ‘Orch OR’ model involves quantum superposition/computation in microtubules within the brain’s neurons. As technological quantum processes require extreme cold and isolation to avoid thermal decoherence, conventional wisdom holds against biological quantum processes in...
The Geometric Universe
April 30, 1998
Stuart Hameroff
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...
The MIT Press eBooks
March 26, 1996
Stuart R. Hameroff, Roger Penrose
82 citations
Abstract 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 -...