Christof KochChristof Koch famously argues that consciousness is a fundamental property of any sufficiently complex thing. This is a variation on panpsychism, that all material objects have a mental component, that mind is universal, that the universe itself is conscious. In a joint article with Giulio Tononi, Koch cited the limitations of panpsychism.
Unlike idealism, which does away with the physical world, or dualism, which accepts both in an uneasy marriage, panpsychism is elegantly unitary: there is only one substance, all the way up from the smallest entities to human consciousness and maybe to the World Soul (anima mundi). But panpsychism’s beauty has been singularly barren. Besides claiming that matter and mind are one thing, it has little constructive to say and offers no positive laws explaining how the mind is organized and worksKoch bases his thinking about consciousness on Giulio Tononi's "integrated information theory" (IIT). In his latest book, The Feeling of Life Itself (p.76), Koch claims that "given some substrate in some state, IIT computes the associated integrated information to determine whether that system feels like something, for only a system with a non-zero maximum of integrated information is conscious." But he also offers this telling disclaimer.
Before I come to the mathematical innards of the theory, let me address one general objection to IIT that I frequently encounter. It runs along the following lines. Even if everything about IIT is correct, why should it feel like anything to have a maximum of integrated information? Why should a system that instantiates the five essential properties of consciousness— intrinsic existence, composition, information, integration, and exclusion— form a conscious experience? IIT might correctly describe aspects of systems that support consciousness. But, at least in principle, skeptics might be able to imagine a system that has all these properties but which still doesn't feeling like anything.
Computational BiophysicsChristof Koch has been a leader in models of information processing in the brain, with single neurons as the logical computing elements, as suggested by Warren McCulloch and Walter Pitts in 1943. In his 1997 Nature article, "Computation and the single neuron,"" Koch wrote
McCullough (sic) and Pitts argued that with the addition of memory, a sufficiently large number of these logical 'neurons' wired together in an appropriate manner, can compute anything that can be computed with a digital computer.Koch did not repeat this claim in his comprehensive 1999 book Biophysics of Computation: Information Procesing in Single Neurons , but he did repeat it a year later in Nature Neuroscience Supplement (vol.3, November 2000, p. 1171), in a joint article with Idan Segev. Koch further exaggerated the claim to "McCulloch and Pitts proved...these simple logical devices are capable of universal computation." No such proof exists. McCulloch and Pitts wrote this article three years before the first digital computer (ENIAC) was actually built. They imagined the brain as a digital computer before there was one.
ReferencesGiulio Tononi and Koch on Consciousness, Royal Society, 19 May 2015 Normal | Teacher | Scholar