This 2007 book proposes answers to questions central to the philosophy of science by building on classical solutions.Under what conditions is a group of scientists rational? How would rational scientists collectively agree to make their group more effective? In this book, Husain Sarkar proposes answers to them by building on classical solutions - the skeptical view, two versions of the subjectivist view, the objectivist view, and the view of Hilary Putnam.Under what conditions is a group of scientists rational? How would rational scientists collectively agree to make their group more effective? In this book, Husain Sarkar proposes answers to them by building on classical solutions - the skeptical view, two versions of the subjectivist view, the objectivist view, and the view of Hilary Putnam.Under what conditions is a group of scientists rational? How would rational scientists collectively agree to make their group more effective? What sorts of negotiations would occur among them and under what conditions? What effect would their final agreement have on science and society? These questions have been central to the philosophy of science for the last two decades. In this book, Husain Sarkar proposes answers to them by building on classical solutions - the skeptical view, two versions of the subjectivist view, the objectivist view, and the view of Hilary Putnam.1. The overview; 2. Group rationality: a unique problem; 3. The problem explored: Sen's way; 4. The skeptical view; 5. The subjectivist view - I; 6. The subjectivist view - II; 7. The objectivist view; 8. Putnam, individual rationality, and Peirce's puzzle; 9. The nine problems.