As tools for measuring consciousness emerge, there is no settled theory of what they measure. This article categorizes tests that infer the presence and complexity of phenomenal or subjective experience, proposing a taxonomy of measurable correlates of consciousness (MCC) with three subcategories: neural, behavioral, and creative correlates. It also suggests ways different theories of consciousness might be empirically distinguished and reflects on how broader philosophical views, such as materialism and panpsychism, could be informed by scientific evidence.
Brain-generated electromagnetic field oscillations are increasingly seen as causal drivers of consciousness. Recent work highlights how the body's endogenous rhythms organize these fields through entrainment. This paper examines evidence of shared oscillations between the brain and other body parts in humans and animals, testing the Slowest Shared Resonance (SSR) principle of General Resonance Theory. The SSR principle states that macro-consciousness in coupled field systems depends on the slowest common denominator frequency. It predicts that a system's SSR decreases with distance between the brain and resonating structures. Observed resonance relationships—between brain and gastric neurons, sensory organs, and spinal cord—generally match these predictions, empirically supporting the SSR principle.