One of the key figures in the development of quantum mechanics was Werner Heisenberg (1901-1976). Heisenberg developed both the first quantum mechanical mathematical framework, matrix mechanics. He also outlined the philosophical basis underpinning it, named thereafter the "uncertainty principle." Even though the practical benefits of quantum mechanics have been unquestionable the philosophical foundations of this scientific theory have been debated since its beginning. An examination of the philosophy of science from the early modern period to the early 20th century will be outlined in the introduction of the following text. A more circumscribed examination of the debate between scientific realism and skepticism concerning the philosophy of science will then be investigated. This analysis will give the necessary context for the intellectual environment that both Heisenberg and Quine found themselves in. Proceeding from this analysis, an examination of Heisenberg's philosophical maneuvering concerning the philosophy of quantum mechanics will follow in the next chapter. Heisenberg's philosophy will then be compared with that of the philosopher Willard Van Orman Quine (1908-2000). The abstract account of how science progresses that Quine provides will be demonstrated to match very closely with that of Heisenberg's philosophical ideas of just how science in general, and physics in particular, makes crucial advances. A process has been taking place within the history of scientific investigation. Scientific methods and theories are often generalized to other fields of inquiry. Crucial understanding of wider issues have been developed by scientists working on small, specialized problems. In this case Heisenberg's philosophy has been generalized by Quine. While both figures make use of positivism in their intellectual toolkit they both also qualify and modify it in several ways when applying this to empirical data. Heisenberg and Quine both opt instead for a pragmatic positivism rather than the more clearly identifiable early 20th century version, logical positivism. The relation between the two is an example of a scientist engaging with philosophy in order to make progress in a chosen field. Quine, as a philosopher, is then able to abstract from the particular case of how to understand quantum mechanics in a theoretical sense and generalize Heisenberg's approach to all of science.