What are the leading scientific theories of consciousness?

The answer

Two dominant theories compete to explain consciousness. Integrated Information Theory (IIT), developed by Giulio Tononi, proposes that consciousness equals integrated information (phi) - any system that integrates information beyond its parts is conscious to some degree, including potentially non-biological systems. Global Workspace Theory (GWT), proposed by Bernard Baars, suggests consciousness arises when information is broadcast across a 'global workspace' of interconnected brain regions, making it available to multiple cognitive processes simultaneously. A landmark 2023 adversarial collaboration funded by the Templeton Foundation tested both theories using neuroimaging and found mixed results: sustained conscious perception matched GWT predictions in frontal regions but aligned with IIT predictions in posterior cortex. Neither theory was definitively confirmed or refuted, deepening the mystery.