124 Are the Androids Dreaming Yet? Their reasoning is straightforward but has generated a great deal of controversy. Hameroff observes that anesthetics cause humans to lose consciousness by binding to tubulin, but they do not halt all brain function. He, therefore, concludes our conscious thinking is mediated by tubulin, not the larger scale firing of the neurons. Penrose had been looking for a mechanism in the brain that would explain how brains solve non-computational problems. Together Penrose and Hameroff propose tubulin micro tubes are quantum gravity computers that allow us to think non-computationally and are the seat of consciousness. The ideas are still being worked. Penrose and Hameroff have a difficult task conveying their ideas to the rest of the scientific community. Scientists don’t recognize a need for something that can think non-computably, so they are highly skeptical of a mechanism which performs that sort of thought. The latest development on the Hameroff Penrose model comes in the work of Travis Craddock, now of Nova Southeastern University, Florida, and others. They have written a paper arguing signals propagate according to quantum principles within microtubules through the excitation of thiamin molecules along the length of the tube. They believe these molecules are quantum, entangled in a similar manner to the mechanism recently discovered in photosynthesis. The geometry of these molecules is set out in a similar way to the active areas in chlorophyll and they have a complementary problems to solve. Chlorophyll tries to maximize energy conversion efficiency, while a microtubule tries to minimize the use of energy while propagating signals along a nerve. You might wonder EXD Aa oe 2 Ow. yf y Lye (CONE eB & es ae a ge 8 ’\ es £ AT Vag a 7 oy ge SO Se, | eh) aS <-eS Aa Wie Tubulin Protein HOUSE_OVERSIGHT_015814