by Alexandre Couto de Andrade
René Descartes claimed that consciousness requires an immaterial soul, the core of our being. Modern science, however, suggests that there is no one central “place” within ourselves where consciousness takes place.
As the philosopher Daniel Dennett puts it, “the brain events that discriminate various perceptual contents are distributed in both space and time in the brain. (…) [T]here is no single, constitutive 'stream of consciousness' but rather a parallel stream of conflicting and continuously revised contents”.
Nevertheless, phenomena like out-of-body experiences seem to defy such arguments. There seems not only to exist a center of the self, but one which is independent from matter. How do out-of-body experiences happen? What does science have to say about them?
Evidence suggests that out-of-body experiences are triggered by malfunctions in a specific area of the brain, called temporoparietal junction (TPJ). It is generally linked to epilepsy, migraines, strokes, brain tumors, drug use and near-death experiences, although healthy people can also have one at some point of their lives.
The TPJ processes sensory information to create a feeling of embodiment, making us know where our body is and where the frontiers between it and the rest of the world are. The out-of-body experiences might arise when the TPJ fails to do this properly.
But how can people who have such experiences see themselves as well as others who eventually happen to be in the same room with them? Another bizarre phenomenon known as sleep paralysis helps shedding some light on it. During sleep paralysis a person can dream of moving or flying while he/she is conscious, yet the brain is aware that the body cannot move. In an attempt to resolve this sensory conflict, the brain might split the self from the body.
But how could someone see what is around him/her while his/her eyes are closed? Something like synaesthesia, yet another strange phenomenon, could be an explanation. The brain could convert acoustic stimuli into visual images.
Time and the Observer: the Where and When of Consciousness in the Brain (Daniel Dennett and Marcel Kinsbourne)
Out of your head: Leaving the body behind (by Anil Ananthaswamy)