Many studies in public understanding of science emphasise that learning how to do science also involves learning about the philosophical issues surrounding the nature of science. This thesis aims to find out how scientists themselves talk and write about these philosophical topics, and how these topics get used in scientific thought. It contrasts scientists' opinions on these issues with how they are portrayed in popular science, and also contrasts them with how philosophers themselves have justified their ideas. Through analysing how scientists talk and write about philosophical topics, it aims to find out what and how scientists themselves think and learn about the nature of science, and what they would like other people to learn about it. 30 popular science books were analysed for how they treat philosophical topics on the nature of science. 40 academic scientists were then asked in a series of semi- structured interviews questions based on the philosophical topics that were found discussed most often in the books. Five philosophical topics are dealt with in detail: The demarcation question of "what is science", the philosophies of Popper and Kuhn, Occam's razor and reductionism, which reflect the most common philosophical themes in the popular science books. In interpreting the books and the scientists' responses on these topics, I use the concepts of boundary work and boundary objects, and social identity theory. It demonstrates that philosophical topics can be used to draw boundaries and to define social identities around science or various disciplinary affiliations. Philosophies and famous philosophers like Popper also act as boundary objects facilitating scientific communication across boundaries. The talk surrounding the various philosophical categories however often hides a big variation in actual philosophical opinion, which is set slightly apart from how the philosophy itself is discussed
