At the very beginning of Hameroff's career, while he was at Hahnemann, cancer-related research work piqued his interest in the part played by microtubules in cell division, and led him to speculate that they were controlled by some form of computing. It also suggested to him that part of the solution of the problem of consciousness might lie in understanding the operations of microtubules in brain cells, operations at the molecular and supramolecular level. The operations of microtubules are remarkably complex and their role pervasive in cellular operations; these facts led to the speculation that computation sufficient for consciousness might somehow be occurring there. These ideas are discussed in Hameroff's first book Ultimate Computing. The main substance of this book dealt with the scope for information processing in biological tissue and especially in microtubules and other parts of the cytoskeleton. Hameroff argued that these subneuronal cytoskeleton components could be the basic units of processing rather than the neurons themselves. The book was primarily concerned with information processing, with consciousness secondary at this stage. Separately from Hameroff, the English mathematical physicist Roger Penrose had published his first book on consciousness, The Emperor's New Mind, in 1989. On the basis of Gödel's incompleteness theorems, he argued that the brain could perform functions that no computer or system of algorithms could. From this it could follow that consciousness itself might be fundamentally non-algorithmic, and incapable of being modeled as a classical Turing machine type of computer. This ran counter to the belief that it could be explained mechanistically, which was prevalent in the field of artificial Intelligence at that time. Penrose saw the principles of quantum theory as providing an alternative process through which consciousness could arise. He further argued that this non-algorithmic process in the brain required a new form of the quantum wave reduction, later given the name objective reduction, which could link the brain to the fundamental spacetime geometry. Hameroff was inspired by Penrose's book to contact Penrose regarding his own theories about the mechanism of anesthesia, and how it specifically targets consciousness via action on neural microtubules. The two met in 1992, and Hameroff suggested that the microtubules were a good candidate site for a quantum mechanism in the brain. Penrose was interested in the mathematical features of the microtubule lattice, and over the next two years the two collaborated in formulating the orchestrated objective reduction model of consciousness. Following this collaboration, Penrose published his second consciousness book, Shadows of the Mind. Over the years since 1994, Hameroff has been active in promoting the Orch-OR model of consciousness through his web site and lectures.
Criticism
This more developed version of their ideas was widely attacked, notably in 2000 by the physicist Max Tegmark, who calculated that quantum states in microtubules would survive for only 10−13 seconds, too brief to be of any significance for neural processes. Hameroff and the physicists Scott Hagan and Jack Tuszynski replied to Tegmark arguing that microtubules could be shielded against the environment of the brain, and that Tegmark had used his own criteria for the reduction of the wavefunction, and did not use Penrose's OR, which is the basic assumption behind the whole theory. In 2014, experimental confirmation of shielding, and most notably of quantum coherence in microtubuli, was found by Anirban Bandyopadhyay.
Hameroff was the lead organizer of the first Tucson Toward a Science of Consciousness meeting in 1994 that brought together approximately 300 people interested in consciousness studies. Hameroff remains co-organizer of this influential annual conference. The first conference is widely regarded as a landmark event within the field of consciousness studies, and by bringing researchers from various disciplines together led to various useful synergies, resulting indirectly, for instance, in the formation of the Association for the Scientific Study of Consciousness, and more directly in the creation of the Center for Consciousness Studies at the University of Arizona, of which Hameroff is now the director. The Center for Consciousness Studies hosts meetings on the study of consciousness every two years, as well as sponsoring seminars on consciousness theory. The conference was described by the Chronicle of Higher Education as "the Stuart Show", and that its "anything goes" atmosphere is damaging the credibility of the field. In 2006, Hameroff participated in the first conference, where his theories were sharply criticized by Lawrence Krauss, among others.
Film
Hameroff appeared as himself in the documentary film What tнe ♯$*! Do ωΣ πow!?. He serves as producer, writer and scientific advisor to an independent feature film called Mindville. Mindville is a feature-length motion picture that combines live action with animation and effects to present a journey into the mysteries of human consciousness.
