(January 16, 2023 at 9:34 pm)Dmitry1983 Wrote:(January 16, 2023 at 6:46 pm)Paleophyte Wrote: all it really demonstrates is that they're using a secondary pathway that doesn't correspond to normal visual perception but clearly is perception nonetheless.What do humans need normal visual perception for if they can function without it?
The standard evolutionary explanation is the so called “other” visual perception pathway is actually the primary pathway responsible for much of the autonomous functions that depends on visual cue, such as balancing, reflexive navigation, path selection and obstacle avoidance in normal walking, reflexive approaching object avoidance, etc. that pathway is also thought to have arisen since very early in the evolution of vertebrate tetrapods. It may even have predated the very first vertebrates.
The “conscious” pathway is in fact a secondary pathway that evolved much later, probably at the same time of t development of the mechanism of consciousness during mammalian evolution.
Exactly how a secondary visual pathway evolved is not known for certain because state of techniques to deducing detailed neurological development of fossilized organisms are in their infancy. However, a plausible reason for this development has been advanced based on duplicate gene scenario.
The duplicate gene scenario is based on experimental observation that one commonly occurring form of mutation during the replication of embryo cell is certain genes are accidentally duplicated. Sometimes when this occurs, the result is as the embryo develope, the organ or parts of organ the the duplicate genes encodes also develop duplicates. If the genes encoding certain pathways in the brain cause the pathway to also be duplicated, and the duplicate does not prove fatal to the embryo and the embryo has a chance to mature, then during the maturation process one set of the duplicates often continues perform the pathway’s original function as expected, while the other set is usually co-opted by the developing brain to perform other functions.
So the theory is the mechanism for consciousness in the brain is artifact of a mutation early during mammalian history which caused a large group of different pathways to duplicate. Offsprings of these mutations than co-opted the duplicate pathways to perform a new set of functions that eventually led to consciousness. But part of the group of duplicate pathways is the pathway for vision. The existence of a spare vision pathway allowed the evolving mechanism of conspicuous ness to integrate it and thus process visual input separately from and in parallel with the primary visual pathway that has existed since before fishes first crawled onto land. This new separate parallel visual pathway is what facilitates our conscious vision.
