Explaining subjective experience (the "hard problem") remains a central challenge in consciousness science. Research on "quantum consciousness" has grown rapidly in recent years, yet a substantial subset merely links terms such as collapse, superposition, and entanglement to qualia in verbal maneuvers that lack testable mechanistic commitments. This article adopts a theory-first critical-review framework and evaluates three classes of quantum theories of consciousness along three axes: (1) physical feasibility in warm, wet neural tissue strongly coupled to its environment; (2) philosophical sufficiency, i.e., a bridge from posited quantum processes to phenomenal character; and (3) empirical testability against classical alternatives. Based on the synthesized evidence, the present review suggests that further progress should prioritize experimentally tractable programs, in order to avoid the use of quantum terminology without mechanistic grounding in consciousness research and to convert debates into discriminating empirical programs.
Explaining subjective experience (the "hard problem") remains a central challenge in consciousness science. Research on "quantum consciousness" has grown rapidly in recent years, yet a substantial subset merely links terms such as collapse, superposition, and entanglement to qualia in verbal maneuvers that lack testable mechanistic commitments. This article adopts a theory-first critical-review framework and evaluates three classes of quantum theories of consciousness along three axes: (1) physical feasibility in warm, wet neural tissue strongly coupled to its environment; (2) philosophical sufficiency, i.e., a bridge from posited quantum processes to phenomenal character; and (3) empirical testability against classical alternatives. Based on the synthesized evidence, the present review suggests that further progress should prioritize experimentally tractable programs, in order to avoid the use of quantum terminology without mechanistic grounding in consciousness research and to convert debates into discriminating empirical programs.
The question of whether quantum mechanical phenomena play a functional role in brain activity and the emergence of consciousness remains one of the most controversial yet intellectually stimulating debates at the intersection of physics, neuroscience, and philosophy of mind. This review systematically examines the principal theoretical frameworks proposing quantum-level mechanisms in neural computation, including the Orchestrated Objective Reduction (Orch OR) hypothesis by Penrose and Hameroff, the quantum brain hypothesis of Stapp, quantum coherence models in microtubules, and quantum field theories of consciousness. We critically evaluate the current state of empirical evidence—including recent quantum biology findings, the challenge of decoherence in warm, biological systems, and experimental observations of quantum effects in biological systems—alongside computational models that bridge quantum formalism and neural network dynamics. Furthermore, we discuss the implications of quantum cognition models for understanding perception, decision-making, and memory. Despite significant scientific skepticism, emerging evidence from quantum biology and advanced neuroimaging technologies provides tentative support for quantum processes in neural substrates. We conclude by identifying critical gaps in current knowledge and outlining future research directions that may resolve the debate, including proposals for experimental paradigms using quantum sensing technologies applied to neural tissue. This review aims to serve as a foundational reference for researchers across disciplines approaching the quantum mind hypothesis with scientific rigor.
The question of what generates conscious experience has mesmerized thinkers since the dawn of humanity, yet its origins remain a mystery. The topic of consciousness has gained traction in recent years, thanks to the development of large language models that now arguably pass the Turing test, an operational test for intelligence. However, intelligence and consciousness are not related in obvious ways, as anyone who suffers from a bad toothache can attest—pain generates intense feelings and absorbs all our conscious awareness, yet nothing particularly intelligent is going on. In the hard sciences, this topic is frequently met with skepticism because, to date, no protocol to measure the content or intensity of conscious experiences in an observer-independent manner has been agreed upon. Here, we present a novel proposal: Conscious experience arises whenever a quantum mechanical superposition forms. Our proposal has several implications: First, it suggests that the structure of the superposition determines the qualia of the experience. Second, quantum entanglement naturally solves the binding problem, ensuring the unity of phenomenal experience. Finally, a moment of agency may coincide with the formation of a superposition state. We outline a research program to experimentally test our conjecture via a sequence of quantum biology experiments. Applying these ideas opens up the possibility of expanding human conscious experience through brain–quantum computer interfaces.
Introduction We saw in Part I that in addition to explaining consciousness there is another hard problem for the modern scientific worldview – understanding what quantum physics is telling us about reality. And if anything this one is harder. In philosophy of mind there is at least consensus enough for an orthodox position to exist (materialism), and a widespread expectation that it will be vindicated by future neuroscience. By contrast, in philosophy of physics all sides understand that quantum theory is compatible with a variety of metaphysical interpretations, and have little hope that new empirical discoveries will settle the matter. But both problems are “hard” in the sense that, despite tremendous intellectual effort over many decades, no clear progress has been made toward solving them. The basic idea of quantum consciousness theory is that bringing the two problems into contact may be the key to solving both (though I will be addressing only the mind–body problem in what follows). That this could be a novel idea attests to the fact that their philosophical discussions have evolved quite separately. While philosophers of physics have long been interested in the role of consciousness in the measurement process, they have engaged little with the mind–body problem per se; and philosophers of mind have been almost unanimous in dismissing the suggestion that consciousness has anything interesting to do with quantum physics. Social scientists might echo such skepticism, wondering how adding the problem of interpreting quantum theory to the problem of consciousness will help them . Besides piling up jargon and arcane debates, in moving to the sub-atomic level we are now even farther removed from the human world, and seemingly poised to engage in the most vulgar reductionism. Yet, naïvely one might expect the two problems to be related, for two reasons. The first is the intriguing analogies mentioned in Chapter 1 between the mental and quantum domains.
Consciousness presents a structural puzzle: a unified, context-sensitive, globally integrated mode of experience emerging from distributed neural dynamics. While classical neuroscience has mapped synaptic, oscillatory, and network-level mechanisms with increasing precision, debate persists as to whether classical formalisms fully capture the integrative and contextual features of conscious processing. This review examines whether quantum principles offer explanatory leverage in two distinct senses: as formal mathematical frameworks for modeling contextual cognition, and as mechanistic hypotheses proposing biologically instantiated non-classical states. We surveyed empirical and theoretical developments spanning zero-quantum-coherence in MRI signals, entanglement-structured learning paradigms, quantum-inspired computational models, and proposed neural substrates, including microtubules, nuclear spins, and photonic architectures. Although certain findings have been interpreted as consistent with a non-classical structure, no study to date has demonstrated entanglement, long-lived coherence, or collapse dynamics in neural tissue under operational criteria comparable to those used in controlled quantum systems. Replication remains limited, biological entanglement witnesses are not yet established, and nonlinear classical dynamics can reproduce many putative quantum signatures. Accordingly, the decisive question is not whether the brain is quantum, but whether its dynamics exceed the explanatory reach of rigorously defined classical models. Progress hinges on replication, adversarial scrutiny, and operational criteria precise enough to discriminate genuine non-classical correlations from classical complexity. Whether quantum mechanisms ultimately prove necessary or refined classical models remain sufficient, this inquiry compels a deeper understanding of integration, contextuality, and the physical constraints shaping conscious experience.
Is mind quantum-like? Is consciousness quantum physical? Does consciousness have a role to play in the emergence of the classical world from the underlying quantum universe? Or is this dichotomy between classical and quantum an illusion? How can world philosophies enrich our views on these matters and interact with the best scientific theories? These are some questions that motivated us to conceive the current book. We also felt an urgent need to discuss the central philosophical questions haunting the emerging frameworks of quantum cognition and quantum-like framework (QLF). We have observed that there are very good technical or mathematical works being done in the emerging fields of quantum cognition and QLF, but there is still a great need for exploring the underlying and open philosophical questions they demand. Quantum cognition developed as a frontier research programme in understanding various cognitive phenomena that are hard or impossible to describe based on classical cognitive science paradigm. Classical cognitive science draws philosophically and mathematically from classical physics and classical probability theory. For example, cognitive realism thinking is deeply motivated by the scientific realism of classical physics. However, as we explore, there are numerous empirical findings which demonstrate clearly that human mind and cognitive processes exhibit features that are more quantum-like. Central to these features are indeterminacy, context dependence, and complementarity of cognitive phenomena, for example, perception, information retrieval, and even qualia. Many good works in the previous decade have demonstrated the efficacy of quantum-like mathematical modelling in such cases. However, given that efficacy, we cannot simply conclude that mind is quantum. Rather there are features that go beyond what is allowed in standard quantum formalism.
It is widely accepted that consciousness at the start of the 20th century was considered mainly in the context of neurology and the mind-body problem belonged to the domain of neuroscience, psychology and philosophy, later broadened by behavioural science and cognitive science. However, these disciplines cannot completely explain the correlation between mental activity and matter. \nChapter one starts by defining the difficulty of determining consciousness. A discussion of how philosophers (such as Descartes, Locke, Dennett and Nagel) attempted to describe this phenomenon leads to the conclusion that firstly, consciousness is indefinable and secondly, it continues to be a challenge for both – philosophy and science – to explain how subjective consciousness fits into the objective world. The following two parts of the chapter focus on the major philosophical theories of the mind-body problem. \nIn chapter two there is a focus on the mutual relation between philosophy and science, physics in particular. However, this project deals more with the implications of science for the philosophy of mind and mind-body problem than the science itself. The second enquiry of this chapter is to point out the difference in philosophical and scientific understanding of the word ‘substance’ (crucial to the mind-body problem). \nChapter three considers quantum theory, since the relation between mind and body started to be tackled from the completely new point of view, after the philosophers began to assimilate the implications of quantum physics. Firstly, there is a short introduction to quantum theory and the most significant points for philosophy and quantum mechanics issues are provided (such as quantum superposition, the measurement problem or the backward causation). Analysis of three prevailing theories is provided. \nThis project addresses the contribution of quantum mechanics to the studies of consciousness and matter and examines whether it helps in solving the mind-body problem.