Jyotish is a language: it is the language of divination. It is a way by which we can communicate with God. Vedic astrology is a divine cryptogram, an intricately coded message that reveals everything about us. Of course, Vedic astrology is not limited to an individual person it can also reveal the fates of nations, corporations, any entity within this world. Such a powerful language is not the product of empirical discovery, but rather divinely inspired and given to us by Lord Krsna Himself, Who transmitted it to Lord Brahma, who in turn transmitted it to the Rsis. It should be understood that because Vedic astrology is a language of divination, it does not cause anything, it only reveals what happens but does not cause it to happen. Because, as a language, it does not cause anything it can describe everything both material and spiritual. Just as an ordinary language can be used to describe the most mundane of secular matters or the most sublime spiritual topics.
For most of us, astrology describes the result of our karma from previous lifetimes, which is fructifying in this lifetime. However, this does not imply that Vedic astrology teaches fatalism or determinism. You always have freewill. Indeed, our everyday life is an interplay between fate and freewill; where fate or karma is the reaction to our previous exercise of freewill. Our fate or previous karma creates a certain situation in which we must exercise our freewill. Thus, you always have freewill. Vedic astrology does not negate freewill; and freewill does not negate Vedic astrology. This may seem paradoxical but actually is not. We shall explain how this can be so.
Most people are familiar with Natal Astrology, which is called Jataka in Sanskrit; this is the horoscope based upon the time of birth. With this horoscope, it is possible to predict many of the life circumstances that the person will find themselves in. It describes the situations which the karma of the individual will place them in that lifetime (we are speaking here of ordinary mortals). But it may, at times, be difficult to predict exactly what the person will do because they have freewill which creates new karma which can create perturbations in the patterns of the previously created karma depending on many intricate factors. Of course, by applying a little psychology, and common sense, one could predict what an individual would do in a given circumstance. But this may not be exact. However, there are other branches of astrology, in particular Prasna and Nimitta, which will reveal the effects of freewill in this lifetime. Indeed, in the text Prasna Marga it is stated that if the result of the Prasna (chart made at the time of questioning) corresponds with that of the Natal horoscope then the result is due to past karma. However, if the result of the Prasna is different from that of the birth chart then the result is because of effects of freewill in this lifetime.