Color Perception: An Ongoing Convergence of Reductionism and Phenomenology

Abstract

Scientific explanation rests on two major approaches. The more familiar is the reductionist or mechanistic explanation in which complex processes or things are analyzed into components and these in turn are reassembled into a working facsimile or restoration of the original object or process. A good example of this is the work done with viruses which can be dissociated into their components (a nucleic acid and one or more proteins) and then reassembled in test-tube conditions without the need for a living host to provide support. At a cellular level such tour de force cases are rare. For the reductionist scientist this is mostly a matter of the cell’s complexity. The second method is sometimes called historical explanation. This is used to interpret time-bound processes. Much of embryology would use this method to explain how an organ forms from its rudiments or from a few initiating cells at some earlier stage of development. A good example of this is a human pseudohermaphrodite with 46, XX karyotype (usually a normal female) who has a penis and a split scrotum leading to a vaginal passageway and internal uterus, oviducts, and ovaries. As one follows the fate of embryonic sexual rudiments and the influence of hormones at particularly sensitive stages one can recreate how such a contradiction to expectation arises. It can be duplicated experimentally in mammals which have a similar sex-determining mechanism. Time also plays an important role in the evolution of species or the divergence of related members of a species. Thus one can study sequences of nucleotides on the Y chromosome or sequences of nucleotides in mitochondria to work out the ancestry of human tribes, ethnic groups, and racial groups. Their origins can then be traced to a common ancestor out of Africa. One can limit the search to the common ancestor from Asia of all native tribes in North and South America. The underlying assumptions for this historical explanation involve mutation frequency and the spread of populations carrying adaptive or neutral mutant changes. Although one cannot do experimental evolution as readily as one can do experimental embryology, studies of Darwin’s finches at the molecular level corroborate field studies that speciation is an on-going process of Darwinian small variations undergoing constant natural selection.