The Aryan Invasion Theory is fabricated by some European scholars to denigrate Indian culture. Some political parties use this theory to exploit the masses.
The earlier proponets of the AIT were not genuine scholars and they had political aims. Max Muller was paid by the East India Company and Lassen and Weber were German nationalists, who believed in the White Aryan Race Theory. Shopenhauer said that they had the knowledge of only schoolboys !
It can be scientifically proved that the hymns of the Rig Veda had been composed by 3700 BC.
The language of the Indus script is based on Sanskrit, the mother of Europe’s languages and the language of the Vedas.
Archeological findings indicate that Indus Valley Civilization can be called as Vedic Civilization.
The movement of the ancient Aryan people, ‘ the Noble Ones’, was from East to West and this is the reason why the European languages have strong association and origin in the Sanskrit language. ( For instance, Mater for mother is Matha, Pather is Pitha or Father, Frater is Bratha or Brother, Septa is Sapta, Octa is Ashta, Nova is Nava and Decem is Dasa ).
No barbaric hordes ever destroyed the Vedic Civilization.
Evidence of an Aryan-Dravidian divide or a South-North divide is never reported by any scripture.
The population living in the Indus Valley and the dried up Saraswathi River practised Vedic Culture. This is what Swami Vivekananda said about the AIT.
Our archaelogists’dreams of India being full of dark –eyed aborigines and the bright Aryans came from- the Lord knows where. According to some, they came from Central Tibet, others will have it that they come from Central Asia .There are patriotic Englishmen who think that the Aryans were all red haired. Others ,according to their idea ,think that they were all black – haired. If the writer happens to be a black haired man, the Aryans were all black-haired. Of late, there was an attempt made to prove that the Aryans lived on Swiss lake..I should not be sorry if they had been all drowned there ,theory and all . Some say now that they lived at the North pole , Lord bless the Aryans and their habitations ,As for as the truth of these theories .there is not one word in our scriotures ,not one ,to prove that the Aryans came from anywhere outside of India ,in ancient India was in included Afghanistan There it ends’
And the theory that the sudra caste were all non –Aryans and they a multitude ,is equally illogical and irrational. Iit could not have been possible in those days that a few Aryans settled and lived there with a hundred thousand slave at their command .The slavse woud have eaten them up, made chutneyof them in five minutes .The only explanation is to be found in tha Mahabharath ,which says that in the beginning of the Satya Yuga there was only one caste ,the Brahmins ,and then by differences of occupations they went on dividing themselves in to different castes and the coming Satya Yuga all other castes will have to go back to the same condition .
[The Complete Work of Swami Vivekananda Vol III Page 293]