The course and nature of the relationship between people and things are further explained through composite charts such as the birth chart. It is a chart most relevant and reveals what things to come in one’s life. It is also difficult to say that it could account for everything by itself but still, there are numbers of people who highly believe in its power. It does not only indicate major and minor events in a person’s life but also determine the brief emotional stats with the temporary transit of the Moon or get a minor cut or burn when Mars hits a certain midpoint. It may also predict having computer problems under a short Mercury transit
There are also techniques and subdivisions that can be applied to the birth chart that seem to show different perspectives of the native’s life. So this sounds that we can’t take into account all of the different factors and minute measurements that stop us from knowing the summary of both the major and minor events in one’s life.
So this brings up the most important point which underlies the questionable ability of a birth chart to reveal everything in one’s life. Yes, it can be but astrologer cannot possible process all of the factors that involved in a person’s chart for the entire duration of their life. But we cannot argue that an astrologer is able to determine everything, be it single major and minor event that will happen to a person. It sounds impossible theoretically but just impracticable.
In modern astrology, there are more tools that can narrow down symbolism that allows for greater precision when we try to determine the particular manifestation a specific placement will take. In this regard, astrologer may not be able to provide detailed prediction; still they will be able to make specific statements about things.
Source : http://horoscopicastrologyblog.com/2011/01/20/does-the-natal-chart-reveal-everything/