In 1848 Phineas Gage a foreman at a construction site suffered a head injury when some workers used dynamite. A metal rod penetrated his skull and disconnected his frontal lobes from the rest of his brain. He did not lose consciousness. He was a conscientious worker but over months he became unreliable as a worker. His acquaintances noticed a certain deterioration in his personality, work ethic and social interactions. Since then similar results were noticed in psychiatric patients subjected to a bi-frontal leucotomy, a surgical procedure misused by many American institutions.
In the nineteen fifties a neurosurgeon named Scoville performed a bilateral temporal lobectomy including the hippocampus, as a treatment for intractable seizures. The patient lost ability to acquire new memories but retained old memories. A surgical procedure was carried out by Kluver and Bucy on monkeys where the temporal lobes were destroyed. The monkeys tended to grasp and put everything they grasped into their mouths, a behavior reminiscent of one year old human children prior to myelination of their temporal lobe connections.
The work by Roger Sperry and Gazzaniga on patients whose epilepsy was treated by disconnecting the left and right brains by a corpus callosectomy, revealed that the left brain controlled language and was a confabulator, while the right brain was more concerned with graphics and orientation. One patient tried to snatch a cigarette from his right hand with his left hand. Another who was given a selective command to the right hemisphere to get up and walk around when asked verbally why he got up confabulated that he was stretching his legs and going to get a soda.
Ladoux and other researchers experimentally destroyed a part of monkey brain called amygdala and found that the monkey lost all fear of its usual predators. Stimulation of the area in human brains during surgery brought on episodes of terrifying fear. Wilder Penfield, a Canadian neurosurgical pioneer stimulated a portion of the brain adjacent to the third ventricle in the brain and elicited bursts of laughter. Certain seizures of the temporal lobe and stimulation of parts of it produced divine epiphanies and patients with such disorders of intense religiosity. Certain streptoccal throat infections are known to produce involuntary movements called chorea, first described by a British physician named Sydenham. More recently there is some evidence that they may cause obsessive compulsive behaviors. The pathology seems to be in a part of the brain called basal ganglia.
Other earlier studies by Broca and Wernicke, French and German neurologists highlighted specific varieties of speech disturbances characterized by loss of spontaneous speech or its comprehension respectively due to lesions in specific brain areas. Other lesions cause loss of one half of the field of vision, inability to read, recognize faces, neglect or denial of the left half of one's entire body and bizarre behaviors.
All these clearly show that judgment, character and behavior are all a function of brain parts and their interconnections that have been perfected by trial and error over eons by evolution. What then is the need for a superfluous god?