anonymous66 wrote: ↑May 27th, 2018, 10:41 amThe problem is to determine just what physical structures are required for consciousness. Do we even have reason to believe that a physical organic brain is necessary for consciousness?I don't think the physical possibility of artificial inorganic, non-biological organs of consciousness can be eliminated a priori. What I reject is the belief in the physical possibility of natural, non-artificial consciousness that isn't realized by and in organic wetware (cerebral wetware, to be more precise).
Have you heard this thought experiment? (I believe it's Searle's): Imagine a man goes to the doctor because he's having some problem with his eyesight. The doctor looks at the scans and determines that there is some degenerative problem with some of his brain cells. But, this is the in the future, and they have the ability to replace the damaged tissue with microchips. The problem is solved. But then, the disease progresses, and they have to replace more and more tissue with microchips until one day, all the patient has is microchips inside his skull. Seems plausible, doesn't it?
And would you automatically reject the idea that we will one day have conscious machines of some kind? On what grounds?
However, there are a posteriori (empirical) reasons to doubt the physical possibility of non-biological artificial consciousness. For example, one of the leading cognitive neuroscientists writes the following in his new book:
"The most surprising discovery for me is that I now think we humans will never build a machine that mimics our personal consciousness. Inanimate silicon-based machines work one way, and living carbon-based systems work another. One works with a deterministic set of instructions, and the other through symbols that inherently carry some degree of uncertainty. This perspective leads to the view that the human attempt to mimic intelligence and consciousness in machines, a continuing goal of the field of AI, is doomed."
(Gazzaniga, Michael S. The Consciousness Instinct: Unraveling the Mystery of How the Brain Makes the Mind. New York: Farrar, Straus, & Giroux, 2018. p. 236)
And the neurobiologist Gerald Edelman (a Nobel Prize awardee) writes:
"The brain is not a computer, and the world is not a piece of tape."
(Edelman, Gerald M. Wider than the Sky: The Phenomenal Gift of Consciousness. New Haven: Yale University Press, 2004. p. 39)
"In many scientific circles, there remains a widespread belief that the brain is a computer. This belief is mistaken for a number of reasons. First, the computer works by using logic and arithmetic in very short intervals regulated by a clock. As we shall see, the brain does not operate by logical rules. To function, a computer must receive unambiguous input signals. But signals to various sensory receptors of the brain are not so organized; the world (which is not carved beforehand into prescribed categories) is not a piece of coded tape. Second, the brain order that I have briefly described is enormously variable at its finest levels. As neural currents develop, variant individual experiences leave imprints such that no two brains are identical, even those of identical twins. This is so in large measure because, during the development and establishment of neuroanatomy, neurons that fire together wire together. Furthermore, there is no evidence for a computer program consisting of effective procedures that would control a brain’s input, output, and behavior. Artificial intelligence doesn’t work in real brains. There is no logic and no precise clock governing the outputs of our brains no matter how regular they may appear. Last, it should be stressed that we are not born with enough genes to specify the synaptic complexity of higher brains like ours. Of course, the fact that we have human brains and not chimpanzee brains does depend on our gene networks. But these gene networks, like those in the brain themselves, are enormously variable since their various expression patterns depend on environmental context and individual experience."
(Edelman, Gerald M. Second Nature: Brain Science and Human Knowledge. New Haven: Yale University Press, 2006. pp. 20-1)