Online research in philosophy

Today we’re talking with Stuart Hameroff, Professor Emeritus at the Departments of Anesthesiology and Psychology, and Director of the Center for Consciousness Studies, at the University of Arizona. Dr Hameroff is best-known for his research on 'quantum consciousness', an alternative model to the accepted view of how consciousness arises. With Sir Roger Penrose, Dr Hameroff has proposed that consciousness arises at the quantum level within structures inside neurons, known as microtubules.

Siewert identifies a special kind of conscious experience, phenomenal consciousness, that is the sort of consciousness missing in a variety of cases of blindsight. He then argues that phenomenal consciousness has been neglected by students of consciousness when it should not be. According to Siewert, the neglect is based at least in part on two false assumptions: (i) phenomenal features are not intentional and (ii) phenomenal character is restricted to sensory experience. By identifying an essential tension in Siewert's characterization of phenomenal consciousness, I argue that his case for denying (i) and (ii) is at best incomplete.

Over the past few years numerous proposals have appeared that attempt to characterize consciousness in terms of what could be called its computational correlates: Principles of information processing with which to characterize the differences between conscious and unconscious processing. Proposed computational correlates include architectural specialization (such as the involvement of specific regions of the brain in conscious processing), properties of representations (such as their stability in time or their strength), and properties of specific processes (such as resonance, synchrony, interactivity, or information integration). In exactly the same way as one can engage in a search for the neural correlates of consciousness, one can thus search for the computational correlates of consciousness. The most direct way of doing is to contrast models of conscious versus unconscious information processing. In this paper, I review these developments and illustrate how computational modeling of specific cognitive processes can be useful in exploring and in formulating putative computational principles through which to capture the differences between conscious and unconscious cognition. What can be gained from such approaches to the problem of consciousness is an understanding of the function it plays in information processing and of the mechanisms that subtend it. Here, I suggest that the central function of consciousness is to make it possible for cognitive agents to exert ?exible, adaptive control over behavior. From this perspective, consciousness is best characterized as involving (1) a graded continuum de?ned over quality of representation, such that availability to consciousness and to cognitive control correlates with properties of representation, and (2) the implication of systems of meta-representations.

Quantum approaches to consciousness are sometimes said to be motivated simply by the idea that quantum theory is a mystery and consciousness is a mystery, so perhaps the two are related. That opinion betrays a profound misunderstanding of the nature of quantum mechanics, which consists fundamentally of a pragmatic scientific solution to the problem of the connection between mind and matter.

There are two versions of the putative connection between consciousness and the measurement problem of quantum mechanics : consciousness as the cause of state vector reduction, and state vector reduction as the physical basis of consciousness. In this article, these controversial ideas are neither accepted uncritically, nor rejected from the outset in the name of some prejudice about objective knowledge. Instead, their origin is sought in our most cherished (but disputable) beliefs about the place of mind and consciousness in the world. It is first pointed out that these common beliefs about mind and consciousness arise from reification of situated first-person experience. Then, situatedness is shown to be a constitutive part of any exhaustive treatment of quantum measurements. It turns out that the alleged connection between consciousness and the measurement problem is a symptom of (i) the ineliminability of our being situated from the end-product of science, and (ii) our difficulty to express correctly this being situated.

In "Brainshy: Non-neural theories of conscious experience," (this volume) Patricia Churchland considers three "non-neural" approaches to the puzzle of consciousness: 1) Chalmers' fundamental information, 2) Searle's "intrinsic" property of brain, and 3) Penrose-Hameroff quantum phenomena in microtubules. In rejecting these ideas, Churchland flies the flag of "neuralism." She claims that conscious experience will be totally and completely explained by the dynamical complexity of properties at the level of neurons and neural networks. As far as consciousness goes, neural network firing patterns triggered by axon-to-dendrite synaptic chemical transmissions are the fundamental correlates of consciousness. There is no need to look elsewhere.

When I look at the scale of the apparatus I know what it reads. Those absurdly delicate, hopelessly inaccessible, global correlations obviously vanish when they connect up with me. Whether this is because consciousness is beyond the range of phenomena that quantum mechanics is capable of dealing with, or because it has infinitely many degrees of freedom or special super selection rules of its own, I would not presume to guess. But this is a puzzle about consciousness that should not get mixed up with efforts to understand quantum mechanics as a theory of subsystem correlations in the nonconscious world. ( David Mermin 1998).

It has been widely thought that consciousness has no causal efficacy in the physical world. However, this may be not the case. In this paper, we show that a conscious being can distinguish definite perceptions and their quantum superpositions, while a physical measuring system without consciousness cannot distinguish such nonorthogonal quantum states. The possible existence of this distinct quantum physical effect of consciousness may have interesting implications for the science of consciousness. In particular, it suggests that consciousness is not emergent but a fundamental feature of the universe. This may provide a possible quantum basis for panpsychism.