That's not how its done. Anthropology and eugenics are not paleontology. There is a beautiful paper in NATURE by Prof. Lalji Singh (amongst other luminaries). There are definite genetic cues that show that we have been a single people for a very very long time.
Perhaps, but then research also suggests that human migration started out of Africa, and all humans are linked to those 'common ancestors', so we are in essence talking about sub-groups within the larger group here, and human migration and evolution on its own is not 'civilization'.
Civilizations that are really old - Egyptian, Persian, Indian, Chinese - they ebb and flow. They spread and seed externally. In turn they are seeded into over time as well.
I don't believe what you described is necessarily applicable to just a 'civilization' - humans have migrated, spread and seeded throughout history. At times that migration, spreading and seeding might coincide with some 'civilization of the time', but the process itself is not tied into 'civilization' and does not, on its own, indicate the dispersion, expansion or dilution of any civilization - it merely points to the nature of humans to 'spread and seed' - I mean, all this points to is our ability to procreate does it not?
But the basic stock of the largest median mass remains the same over millenia. The others are merely statistical outliers, where time and popu.lation form the dynamic denominator.
Sure, but that is pointing the obvious is it not? All humans originated from a common ancestral source did they not?
I thought you wanted a serious discussion. Why bring in deity worship? Is that all your mind turns to when we talk civilizations? Faith is faith. Be it deity, or nature, or inanimate objects, or books, or formless conceptual higher powers, or otherwise. We could do so much more if we stick to conceptuals.
No need for knee jerk peevishness - Faith, as in religion, does involve worshiping a deity/deities, whether they be God, Allah, the Sun, Rain, Nature, Zeus, or Hanuman, and that was the context in which I used the term.
So if we can return to the question, what sort of 'common faith metric' are we looking at here, and how can this metric be defined t be exclusive to one set of people vs another, to imply civilizational continuity for the former set of people?
For a long enough period of time. Parsis have been here for 1300 years. The Indo Aryans maybe 5-8000. The Dravidians/IVC much more. The civilization remains constant on the land it is linked to. Outsiders get absorbed. Export seeds do not form metastatic or satellite moieties in turn. Unless there is en masse genocide and replacement in large enough numbers. Then the civilization is exterminated. And replaced by a new one.
How would Parsis be part of the same civilization as, say, those practicing the Vedic faith or its offshoots? Does that not remove one of your major metrics for civilizational continuity?
And while you have offered your opinion on 'long enough', is your definition of 'long enough' not one merely pulled out of a hat by you? Is it not subjective? Why not exclude any group of people resident for less than 5000 years, or 10,000 years?