In this book the author comments briefly on seven of the 8 main Indian philosophies and shows the reader how nonsensical they are. He then looks at the eighth of the 8 philosophies, states that it is the best in the world and logically flawless. However, the author replaces some of the assumptions in this eighth philosophy to propose what he believes to be a better philosophy. From an academic point of view, the two philosophies are similar. As with all science, they start off with assumptions, proceed with analysis and then draw conclusions. From a practical point of view, the two philosophies are similar. The conclusions reached are that you should help the nice people you meet become happy. This is your purpose in life. From another practical point of view, the nice thing about these philosophies is that they both include an assumption that God exists. They are rich in content. This means that they tell you a lot about the world, about yourself and so forth. They are unlike Western philosophy, where the subject matter is usually two or three specific points selected for academic debate.
But just because they assume that God exists does not mean that they are "unscientific". The definition of a science is the one given above and further, any science which does not have useful content is not used. For example, one could take the case of Western philosophy: never used, only debated in academia.