Evolution has not only produced millions of different species; it has also produced millions of different transducers. Our bodies are encased in transducers that convert distinctive properties of electromagnetic radiation, air pressure waves, airborne chemicals, liquid-borne chemicals, textures, pressure, and temperature into similarly distinctive patterns of electrical and chemical activity in the brain. What if, at some point - perhaps when humans first developed language and consciousness - the random mixing of genes produced a brain that could send signals to and receive signals from an alternate universe? Unlike string theory or theories of parallel universes, the theory that the brain is bidirectional transducer is directly testable, and empirical support for this theory has the potential to profoundly change our understanding both of ourselves and of our universe. It will help to explain, in rational and objective terms, more than 50 odd phenomena that have baffled humans for eons, among them: dreams, hallucinations, schizophrenia, and even claims about bizarre experiences such as demonic possession and communication with the dead. Neuroscience has been hamstrung for half a century by its reliance on the information processing model of the brain - a metaphor that has shed no light on how the human brain actually works. Let’s set aside the metaphors we have used for 2,000 years to "explain" human intelligence. Transduction theory is a testable theory consistent with evolutionary theory and with three core theories of modern physics - string theory, inflation theory, and quantum theory - each of which predicts the existence of alternate universes.