Q: In exactly what context does astrology exist in Vedic philosophy?
There are six primary and largely complimentary schools of Vedic Philosophy: (1) Pūrva and (2) Uttara Mimaṁsa – which are primarily focused on textual analysis and practice of the Vedas themselves; (3) Yoga and (4) Samkhya – which are primarily focused on clearing the mind, the tool of perception; and (5) Nyāya and (6) Vaiśeṣika – which are primarily focused on science and logic.
Astrology is an important part of the school called Pūrva-mimaṁsa – which is the school that focuses on practicing the rituals in the “four vedas” – Ṛg, Sāma, Yajur, and Atharva.
Q: How was astrology used in Vedic culture?
It is one of the six ancillary disciplines (vedāṅga) required to correctly utilize the four Veda. The six Vedanga are: (1) Pronunciation – śikṣā, (2) Poetic recitation – chanda, (3) Grammar – vyākaraṇa (4) Word meaning – nirukti, (5) Milestones – kalpa, and (6) Astrology – jyotisha.
The fifth and sixth, astrology and milestones, are meant for determining the right times to perform Vedic ceremonies and rites. That is the primary purpose of Jyotisha, it is not natal astrology. At best, it could be similar to electional astrology (“muhurta”) – which selects the best time to do a particular deed.
There was prognostication for individuals, especially important individuals like kings. But it was not limited to astrology, and may not have even included astrology. There is no compelling reason to believe it was the sign, planet, house natal astrology system that is called Vedic Astrology today.
Q: What is the purpose of Natal astrology?
It has many purposes, but the ultimate is to understand your karma – the types of situations that will occur in your life. By knowing that, you can understand what sorts of mistakes and successes you must have done in your past lives, and can also know how to deal with your situations in a way that will not create unwanted results.
Q: When did the psycho-social interpretation of natal astrology come into being?
It came into being in many different ways, in many different places, at many different times. In India, the evidence I have seen seems that show that it became prominent as a result of their exchange with Yāvanas (Greeks/europeans) and Tajjikas (Persians). The house/sign/planet system we are familiar with today, seems to have come mostly from there, but the Indians wove it into their own fabric, and developed it in their own way, improved it in many ways, and created something distinctly unique.