"The idea has recently been challenged by archaeologists, who ― along with linguists ― are best qualified to evaluate its validity. Lack of convincing material (or osteological) traces left behind by the incoming Indo-Aryan speakers, the possibility of explaining cultural change without reference to external factors and ― above all ― an altered world-view have all contributed to a questioning of assumptions long taken for granted and buttressed by the accumulated weight of two centuries of scholarship."