| 07-10-2009 07:20Wider than the Sky: The Phenomal Gift of Consciousness
Gerald Edelman's short book on how the brain produces consciousness may convince a lot of people that consciousness is not a mystery, but a scientifically approachable phenomenon. There are three issues I have with Gerald Edelman's point of view.
First, he keeps insisting that the brain is not a computer. If he means that the brain is not a 21st century PC, he's right. However, if he means that all comparisons are misguided, he's wrong. Each neuron is a cell in which only genetically preprogrammed processes are going on. They read input and produce output. The brain then is a self-organizing network of 10 billion simple computers, which can - in theory - be simulated by a single computer. Also, the brain's 'task' is to make sense of multiple streams of complex sensory input to produce competent behavior as output. If we refuse to see the brain as a biological information processing device - bound by the laws of physics, there is no way we can make sense of what it does. In this light, reviewing the similarities and differences between computers and brains is necessary.
Second, Edelman repeatedly states that consciousness has no causal effect on what we do and think (he puzzlingly adds that consciousness is not an epiphenomenon). He also states that consciousness is the only way to access certain information, suggesting that we need this for some purpose. If this information is used then consciousness has causal effects.
Third, Edelman says that Qualia are high-order decicions. Qualia however are not arbitrary. Colour perception is tightly linked to light frequencies and characteristics of the environment we evolved in, and is pre-processed in brain centres (retina, LGN, V1) in mostly genotypically determined ways. There is nothing to decide there. Indeed there are striking similarities in colour-experience, making Qualia accessible for scientific inquiry.
That said, Edelman's hypothesis of what anatomy and interactions produce consciousness are at least thought provoking. The book is very short, so I'm hoping Gerald Edelman did not do his own theories justice for the sake of brevity.