A review of five physical approaches to consciousness—von Neumann–Wigner, orchestrated objective reduction, integrated information, consciousness as a state of matter, and electromagnetic field—finds that all except the von Neumann–Wigner approach agree the brain generates and detects consciousness, though they offer distinct explanations. None of the approaches are close to experimental verification, and further work on experimental design and new theories is needed.
Consciousness shapes how reality, including ourselves, is perceived and defines personal identity through experience. It is central to unresolved problems in physics, such as observation and the measurement problem, yet its nature, brain mechanisms, and universal location remain unknown, making it a key scientific challenge. This review examines physical processes linked to consciousness, including signal transmission in the brain, chains of events, quantum phenomena, and integrated information. It also discusses the roles of matter structure, fields, and universality. The authors propose further studies to improve understanding of consciousness.