How human consciousness arises has always been a great mystery.  There are many theories, but none come close to explaining it.  The main problem is explaining how something subjective like conscious experience arises in something physical like the brain.  This is known as "the explanatory gap" or "hard problem of consciousness".  Many think this is unexplainable.  We also have the proliferation of many theories portraying consciousness as being non-physical, epiphenomenal and mysterious, not scientifically explainable.  However, when relativistic principles are applied, consciousness can be seen to have a physical basis and can be explained scientifically.                                                                                                                                                                  
Conscious experience is defined as the direct observation of conscious events.  It makes up the content of consciousness.  In humans, knowing the world occurs through spatial-temporal experiences and interpretations. If we examine our current conscious experience, we observe that many conscious events are observed simultaneously, but in different three-dimensional spatial positions.  Other conscious events are observed at the same spatial positions, but at different times.  If one examines the accompanying pictures, one can see this organization of conscious experience.  This organization is typical and characteristic of conscious experience in general. This organization shows that human conscious experience is organized in four dimensions (three dimensions of space, one dimension of time).  Space is often conceived in three linear dimensions, but modern physicists usually consider it with time as part of a boundless four-dimensional continuum called spacetime. Spacetime is any mathematical model that combines space and time into a single continuum.  Consciousness is a spacetime continuum.  The most successful model of spacetime is Einstein's special theory of relativity.  Spatial and temporal cognition have been found to implement a systematic framework for the association of events and the organization of experiences and special relativity is a viable model of this system.
The neural correlate of this system consists of the entorhinal cortex (grid cells), hippocampus (place cells and time cells, computation of spacetime intervals), posterior parietal cortex, and prefrontal cortex (integration of spacetime interval relations and the organization of conscious experiences, assessment of causality, direction of cognitive functions, and implementation of goal-directed actions).  A spacetime interval is the separation of two events in spacetime.  There are three types of spacetime intervals:  light-like intervals account for the experience of conscious events;  space-like intervals account for the experience of conscious events simultaneously, but in different spatial positions;  time-like spacetime intervals account for the experience of conscious events at the same spatial position, but at different times.  Spacetime intervals are fundamentally involved in the organization of conscious experience.  They account for why conscious experience appears to us the way it does.  Spacetime intervals also enable assessment of causality and past-future relationships, the integration of higher cognitive functions, and the implementation of goal-directed actions.  Spacetime intervals in effect direct our conscious life.  
The relativistic concept closes the explanatory gap and solves the hard problem of consciousness.  It establishes a place in physics for consciousness.  We describe all physical phenomena as conscious experience, whether they are described at the quantum level or classical level.  In accordance with Bohr's correspondence principle, quantum mechanics is reduced to classical physics in the correspondence limit of conscious experience.  Bohr provided a rough prescription for this limit:  it occurs when the quantum numbers describing the system are large, ie.  classical physics and quantum physics give the same answer when the systems become large.  It is accepted that the quantum description of large systems closely approximates the classical description (Copenhagen Interpretation).  Since spacetime intervals direct the formation of all conscious experiences, the equation formulating spacetime intervals might be considered expression of a "Theory of Everything".  A theory of everything is a fundamental all-encompassing theory which explains the derivation of all observable phenomena.  This is exactly what the equation formulating spacetime intervals does-it explains the derivation of all observable phenomena.

Space-Time Intervals Underlie Human Conscious Experience, Gravity, and a Theory of Everything: Conference Talk Notes (Science of Consciousness, Tucson, 2018).
Intervals talk.pdf