Scientific Understanding of Consciousness
Nature 510, 474 (26 June 2014)
Obituary -- Gerald Edelman (1929–2014)
Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York
Edelman died on 17 May in La Jolla, California. Born in Queens, New York, in 1929, he studied medicine. He then turned to immunology and spent most of his research career at Rockefeller University in New York. His focus on the structure of antibodies in the 1960s led to the 1972 Nobel Prize in Physiology or Medicine, which he shared with Rodney Porter. The award recognized Edelman's work on the descriptions of the heavy (H) and light (L) polypeptide chains, and Porter's on the distinct binding domain (antigen-binding or Fab fragment) of antibodies (also called immunoglobulins). These were the first dominoes to fall in the elucidation of the structural variability that lies at the heart of antibody-based recognition of infectious agents such as bacteria and viruses.
Edelman was fascinated throughout his career by the enormous explanatory potential of selective-recognition systems. These had already been used to attack and elucidate two of the most challenging problems in biology: the evolution of species and the adaptive immune response. Darwinian evolution of species depends on fitness-based selection from a repertoire of variable genetic traits; the immune system recognizes foreign substances by selecting from a repertoire of antigen-recognizing cells.
Over about the same period as the antibody studies, two fundamental properties of neurons and their synaptic connections were discovered by different teams: that cortical neurons are organized into discrete groups of cells, and that synapses strengthen through use.
Edelman reasoned that the formidable recognition and processing capabilities of a complex nervous system depend on selection operating on cell groups that differ in their connectivity patterns.
Incoming sensory information would elicit a response from distinct cell groups; it could be modified by repetitive recognition (termed re-entry) that provided opportunities for strengthening, abstraction and association.
Thus the simplicity of repeated selection from an evolving repertoire could account for the astonishing information-processing power of sophisticated neural systems.
Edelman presented this idea in several books, including Neural Darwinism (Basic, 1987), Bright Air, Brilliant Fire (Basic, 1993) and A Universe of Consciousness (Basic, 2001), which was written with colleague Giulio Tononi. The descriptions and arguments are often dense and elaborate, (Model of Core Consciousness), (Consciousness and Complexity), viewed by some readers as possessing an admirable literary quality, and by others as redundant and opaque.
Given his multidimensional background and relentless intellect, it is not surprising that Edelman was a complicated and controversial individual, in his research and his relationships. He could range from charming and inspiring to arrogant and abrupt. Although colleagues often found him abrasive, in his group Edelman could be an effective and generous leader. He sustained collaborations with several prominent scientists,
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