To reduce the severity of his seizures, Joe had the bridge between his left and right cerebral hemispheres (the corpus callosum) severed. As a result, his left and right brains no longer communicate through that pathway. Here's what happens as a result:
I heard about this years ago in a psychology class. There was a specific example of two very disparate things shown to the two different eyes. I wish I could remember the example, because at the end when the person tested was asked why the hand drew one thing but he said another with his voice, he gave a completely rational explanation as to why his hand might have drawn something that didn't seem to fit.
What the neuroscientist here describes as the last step that has to generate a consistent theory of what's going on in our mind is what I call the "bullshit generator," that tries to rationalize why all the product of all our vaguely independent subsystems or agents are "really" consistently after all. "Really, I'm an individual!"
This makes me wonder what other people would do if they were presented with the dilemma of either one condition or another to live with. If a doctor said to you that you have a life threatening condition, would you be willing to live as this man does instead? I'm sure it would be tremendously confusing for him.