Materialism › Neurobiological
Merker’s Midbrain-Centered Reality Space
Consciousness as a Midbrain Simulation of Body-in-World
Björn Merker argues that basic phenomenal consciousness is generated by an ancient upper-brainstem system, centered on the midbrain, that can work without the cerebral cortex. This system runs an analog simulation of a body nested in a world around an implicit ego-center, letting the animal match needs to opportunities; the cortex enriches the content of that simulation but does not constitute it.
Björn Merker
What consciousness is
Consciousness is the structured analog simulation, or ‘reality space’, in which a simulated body sits inside a simulated world around an ego-center, colored by motivational bias.
Mind and body
Phenomenal experience is the mode of function of a specific brain architecture: the format of a neural simulation built to solve a control problem.
Mechanism
The selection triangle: target, action and motivation constrain one another inside a shared analog simulation, and the structure of that simulation is a conscious mode of function.
Core claims
- Penfield and Jasper found that removing large sectors of cortex, even a whole hemisphere, never interrupted the continuity of consciousness.
- Decorticate rats groom, play, mate and raise pups, and decorticate cats solve visual discriminations.
- Shewmon and colleagues judged four congenitally decorticate children conscious by ordinary neurological criteria, and Merker reports their preferences and pleasure.
- Merker predicts that no change in conscious content occurs without mesodiencephalic involvement, citing collicular activation during an audio-visual illusion under fixation.
Criticisms
Critics object that organized behavior in decorticate animals and children does not establish phenomenal experience. Merker replies that classifying such children as vegetative assumes the cortex-consciousness identity under dispute.
Implications
- AI consciousness: Uncertain
- Merker ties consciousness to a specific simulation architecture; whether an artificial system implementing the selection triangle would be conscious is left open.
- Survival beyond death: No
- Since consciousness is the function of a midbrain simulation, it ends with the brain.
- Meaning and purpose: Humanistic only
- The theory explains consciousness as a solution to a biological control problem.
- Virtual immortality: Uncertain
- The theory does not address simulated continuation of a person.
Related theories
- Panksepp’s Primal Affective Consciousness (Compatible)
- Damasio's Homeostatic Feelings and Emergence of Consciousness (Compatible)
- Baars's and Dehaene's Global Workspace Theory (Contrast)
- Solms's Affect as the Hidden Spring of Consciousness (Overlap)
Sources
- Consciousness without a cerebral cortex: A challenge for neuroscience and medicine, Björn Merker (2007)
- From probabilities to percepts: A subcortical global best estimate buffer as locus of phenomenal experience, Björn Merker (2012)
- The efference cascade, consciousness, and its self: Naturalizing the first person pivot of action control, Björn Merker (2013)
- Epilepsy and the Functional Anatomy of the Human Brain, W. Penfield and H. Jasper (1954)
- Consciousness in congenitally decorticate children: Developmental vegetative state as self-fulfilling prophecy, D. A. Shewmon, G. L. Holmes and P. A. Byrne (1999)
- Sound alters activity in human V1 in association with illusory visual perception, S. Watkins, L. Shams, S. Tanaka, J.-D. Haynes and G. Rees (2006)