Similar reductions have taken place in the history of science:
water = H20
visible light = EM-radiation at certain wavelengths
temperature = kinetic energy molecules
pain = neural impulses in C-fibers
seeing red = synchronization of neural activity at 40Hz in V4
Yet a main criticism of this theory is that it leaves out qualia--what it is actually like to see red, or feel pain, or experience anything.
See also: The mind-body problem, Monism, Materialism, Physicalism, Eliminative materialism, Emergent materialism