In summing up his extended survey of linguistic evidence Witzel tells us that the mode of the IA entry is "archaeologically still little traced"; it … - Nikos Kazanas

I start with some literary evidence. RV 4.1.13 & 4. 2.16 the Angirases declare that their ancestors made sacrifices “here” atra, ie in Saptasindhu. 3.53.11 Sudās fought enemies prāk ‘east’, apāk ‘west’ and udāk ‘north’ only, but not south. So we have no Indoaryans coming from the north and driving natives southward. The movement here is from east westward (apāk) and from south northword (udāk)! M6.61.9,12: Sarasvatī, the Rivergoddess, spread all five tribes beyond the other seven sister-rivers as the sun spreads out the days – again, days and sunlight from the east! 7.6.3 Agni turned the unholy Dasyus from east to west –pūrvaś cakāra áparām! Notice – NOT SOUTH (avāk or nyāk).

The odd thing about this story is that the heliocentric view was known in Europe long before Copernicus but, for various reasons, was totally ignored by the "established" dogma... All this time all kinds of absurdities were written about the heavens, the celestial spheres, the Empyrean and so on, which constituted the “established” view. And all the time the real knowledge was there and all those schoolmen, could, with some practical observation and sensible application of Mathematics, have found out that the Ptolemaic system was not true. But they did not: they preferred to argue about such weighty matters as how many angles could sit on the point of a pin. And when the proofs were presented to them in black and white, hard and irrefutable mathematical demonstrations, they still rejected them preferring the comforts of the ‘‘established” dogma. Theology (and Church interests) decided what was acceptable, not Mathematics.

I have seriously changed my mind on this subject; I have no axe to grind, as it were, no position or reputation to maintain; I can and shall change my mind again if strong and sufficient evidence emerges. Prof Witzel raises many points for discussion - some useful, some wasteful - but offers no evidence other than conjecture. Conjecture or hypothesis is not admissible as evidence in any impartial Court of Law.