My article, “Vedic Astrology?” established that the excellent astrological system of modern India is a hybrid of Indian, Greek and Persian astrological culture. I got one interesting reply:
Only one critique I can make is that by dating written literature you are not considering how knowledge was passed down from teacher to the student in verbal form before it got written and codified. Simply by dating the written literature we cannot say that the concepts in that literature are not ancient and Vedic.
This is a good concept, but I think it is blown out of proportion and context very often. We find that knowledge is written down fairly close to whenever it originates. The exception to this is in extremely ancient times when human beings had excellent memories and did not much require writing. The truth of the matter is that the Purana’s explicitly tell us that at the end of the second age and beginning of the third, Vyasadeva took the one Veda and began expanding it. The Purana (I am particularly referring the the Bhagavat Purana) say that over the course of thousands of years he and the people he entrusted developed four schools with libraries (standard texts of the four Veda and their ancillaries). Thus all these works have valid dates. Then Vyasa also developed a fifth school for the Purana and Itihasa. And at the end of all this development he produced the final purana, Bhagavata Purana as the culmination of everything in the Vedas and their ancillaries (especially the Upanishads and Vedanta), the Puranas, and Mahabharata.
Thus all Vedic literature is documented and all of it is placed on a historical timeline. Yes, the concepts within this literature are timeless, but the literature which expressed and expanded those timeless ideas all have a particular place on a historical timeline.
The only writing on this timeline that is historically “ancient” and has to do with astrology is an appendix to the Rg and Yajur Veda called “Jyotisha.” This booklet has a few dozen texts. There is nothing else documented as having been written about astrology, therefore anything written in India on the subject must have been written after the completion of Srimad Bhagavatam.
Astrology itself allows us to accurately date everything, and by astrology we can tell the date at which a book describing the heavens was written. The Surya-Siddhanta that we currently have was written in post-ancient times. All the other books on astrology were written still later.This we know by astrologically dating the stellar observations recorded in the books, and by cross-referencing the historical information given in the books themselves.
Thus we know beyond any reasonable doubt that the astrology of ancient India was extremely different than the astrology of modern India. The astrology currently practiced in India involving planets, signs and houses is not the “Vedic” astrology of ancient India. It is not the science developed by the ancient sages. Rather it is a mixture of that ancient science with similar sciences imported into India during classical times from yavanas (Greeks) and tajjikas (persians).
Vedic astrology was one thing and modern Indian astrology is something else, still distantly related but now dominated by the planets, signs and houses of Greeks and Persians.
In Bṛhatsaṃhitā (2.32) Varāhamihira himself says so: mlecchā hi yavanās teṣu samyak śāstram idaṃ sthitam: “The Yavanas are foreigners. They are the best authority on this [astrology].”
– Vic DiCara