6 ideas
During development, variable populations of interconnected neurons form a primary repertoire within constraints set by genes and developmental processes. Experience then strengthens the synapses of groups whose activity matches adaptive behavior while others weaken. Edelman likens this to natural selection: genes constrain brain development without specifying its detailed wiring, and the environment selects among the variation that results.
Reentry is ongoing, reciprocal signalling along massively parallel fibers between separate neural maps, such as different visual areas processing color and motion. It is not feedback around a single loop. It lets these areas coordinate their activity in time and bind features into coherent perceptual categories without a central supervisor or master map.
Brains lack fixed codes, precise wiring, and a clock, and the world presented to them is not pre-labelled with categories. So the brain cannot be executing algorithms on symbolic input as a Turing machine does. Individual brains differ degenerately in structure yet reach similar functions, which fits a selectional system and does not fit an instructional one.
Any recognition system either receives information that directs how it is built (instruction) or generates a diverse repertoire in advance and lets the environment pick winners (selection). The immune system was once assumed to be instructional but proved selectional, since antibodies pre-exist the antigens they recognize. Edelman applies the same diagnosis to the brain.
Primary consciousness is a 'remembered present': reentry links current perceptual categorization with value-laden memory, producing an integrated scene tied to the immediate moment, as many animals may have. Higher-order consciousness adds semantic capability and, in humans, language. This allows a concept of self, past, and future, so that one can be conscious of being conscious.
Selection needs criteria, which evolution supplies through brainstem and limbic value systems that signal what matters to the organism's survival, such as hunger and pain. Meaning therefore arises from a body interacting with its environment and history, not from formal symbol manipulation. This rules out both Cartesian dualism and disembodied functionalism.