Humans can build machines to re-create conditions seconds after the Big Bang and send a probe to the surface of a one of Saturn's moons. But no one can explain how experience happens — how we smell garlic, for example, or see colors.
Those small things and every other sensory event that we toss under the heading of "consciousness" mark the edge of a scientific frontier that four professors in Southern California plan to chart, using the latest techniques from mathematics and quantum theory.
They begin their expedition with an elemental question: What is real?