The idea for this book arose from a sense of discomfort. I had always felt this when I engaged in philosophical discussions with friends, acquaintances, or colleagues who were unfamiliar with the sciences, trying to provide insight into a physicist's worldview. I was always frustrated afterward. At first, I believed I simply hadn't found the right words quickly enough, but soon I realized that the problem ran deeper. It lies in the differences in prior understanding, in the perspective on which questions are interesting, and which knowledge and skills are particularly worthy of protection. One internalizes the self-understanding of a discipline over many years through a kind of intellectual socialization, and it cannot be easily conveyed to an outsider. Now that I am retired and no longer practicing physics, but still thinking about it, I wanted to capture these thoughts in a book.