Complex Brains

31 May 2013

At ... a blog post with an interesting video to watch, Carl Sagan and Roger Penrose discussing the neocortex and the make-up of the human head (and the complexities of the brain). According to Penrose, what is in our heads is orders of magnitude more complex than anything one sees in the Universe. Our brains are a tiny part of the cosmos but they are perfectly organised.

Each cubic millimetre of tissue in the neocortex, says Michael Choret in World Wide Mind, contains between 860 million and 1300 million synapses. The total number of synapses in the neo cortex can only be estimated - ranged between 164 and 200 trillionh. The neocortex has the same number of neurons as a galaxy has stars - one hundred billion.

Elsewhere in the brain, in the cerebellum, one type of neuron has 150,000 to 200,000 synoptic connections with other neurons.

Richard Dawkins in his book, The Ancestor's Tale, said the universe could so easily have remained lifeless and simple - just physics and chemistry, just the scattered dust from a cosmic explosion (the Big Bang idea). The fact it did not - the fact that life evolved out of literally nothing is a fact he found quite staggering. Not only did evolution happen, he said, it eventually led to beings capable of comprehending the process.

Carl Sagan in hios book Cosmos, said the neocortex is where matter is transformed into consciousness. It comprises two thirds of our brain mass. It is where we have ideas and inspiration, where we read and write, where we compose music or do mathematics.

Roger Penrose, in The Emperor's New Mind (1989) argued that known laws of physics are inadequate to explain the phenomenon of consciousness. He argued against the view that the rational processes of the mind are completely algorithmic and can be duplicated by a complex computer. This contrasts starkly with believers in artificial; intelligence, simulated algorithmically. Penrose claims consciousness transcends formal logic and quotes philosopher John Lucas of Merton College in Oxford. The subsequent Penrose?Lucas argument regarding human intelligence has been widely criticised - by mathematicians and computer scientists, and by philosophers. Critics choose different points in the theory to attack and artificial intelligence 'believers' are especially critical. Some of these people see humans as virtually machines, where functioning is fully explained by known physics - which has to be doubtful, surely. Penrose and Lucas, on the other hand, say the opposite - human thought is not based any known scientific principle.

In Shadows of the Mind (1994) Penrose continued his observations with those of anesthesiologist Stuart Hameroff, where they came up with 'orchestrated objective reduction' and this was developed further by Hameroff et al in Physical Review E where it supposed that the interiors of neurons would alternate between liquid and gel states. In the gel form it was hypothesized that the water electrical dipole are oriented in the same direction, and at the outer edges etc. At this point the reader is advised to read the piece on Daily Galaxy and the following comments.

Finally, Penrose and Hameroff, in a 2011 paper, presented an update to their theory and tried to answer their critics, discussing the place of consciousness within the universe, a fascinating concept. See also which is not particularly favourable to Penrose, casting him as a minority view.