 That Althusser regards most, if not all, human activity as consisting of material processes of production and reproduction can be used as a key to understanding other parts of his philosophy. These include his thoughts on the structure of the social and political world, the historical process, and philosophy. As philosophy is closely related to science and because it is charged with a task that allows the production of knowledge about the other socio-economic practices to be generated, it is probably best to start with Althusser’s understanding of philosophy as a material practice of production before proceeding to a discussion of how Althusser understands the other practices listed above.