First, the paper argues that Tarski's theory of language levels is best understood not only as a method for avoiding semantic paradoxes by rigidly restricting the expressive power of a language, but as a natural expression of an epistemological process of reflection which is more adequately understood as a process and not by its result. Second, it is argued that the apparent philosophical controversy between materialism and idealism dissolves whithin this process of reflection. If one has raised above the lowest (...) level, one always is a materialist as well as an idealist; however, one is so in relation to different levels. (shrink)