This thesis advances the argument that Kelsen‘s pure theory of law still has the potential to inform and inspire critical legal research in the postmodern world. The common view that pure theory represents an outdated, state-centric theory of law is rejected through a creative re-reading of Kelsen‘s seminal theory, which traces both its critical iconoclastic ambitions, and the limitations imposed on these ambitions by Kelsen‘s purist methodology. To illustrate this tension, the thesis focuses on Kelsen‘s Grundnorm (basic norm) concept. The Grundnorm represents the presupposed foundation of law, a feigned ground of objective legal validity representing law‘s binding power, mode of existence, and unity. The Grundnorm concept is a positivist answer to the theories that derive legal validity from substantial – yet elusive – natural law. Kelsen‘s Grundnorm does not prescribe the content of a legal order, and this position is often interpreted as dangerous, even nihilistic. Many attempts have been made to rearticulate the formal Grundnorm into a substantial concept grounding law in the values of liberalism. This project, in contrast, embraces the emptiness of the Grundnorm as pure theory‘s commitment to the critical treatment of law. Kelsen insists that law is a human-made and thus constantly transforming phenomenon – a phenomenon potentially dangerous or redeeming. Pure theory is, accordingly, envisioned as a dynamic theory of law. Nevertheless, owning to the rigorous epistemological norms enforced by Kelsen, the Grundnorm remains trapped in a linear conception of time and is spatially imagined as a single point supporting a legal system. To engage with both critical potentialities and limitations of pure theory and its Grundnorm, this thesis reads them through the works of Heidegger, Derrida, and Nietzsche. In this process, the Grundnorm is simultaneously affirmed and destroyed – rearticulated as a multiplicity, a perspectivist Grundnorm(s) that nevertheless retains the most important critical insights of pure theory.