'caste' should be seen as another relic of middle ages, like burning at stake, many abhorrent forms of entertainment of ancient Rome, to name a few, all of them fiercer than the comparatively harmless 'caste'. There is less purpose served by this(quest of origin) than finding out 'how come caste still remains in our society, albeit in fiercer form, whereas all these other 'entertainments of middle ages' gave way to something less reprehensible.