This book, in the form of a classical philosophical treatise, presents a large-scale theoretical project: It uses a metaphilosophical perspective to present the framework for postmetaphysical thinking, situating it in the domain of the metaphysics of morality. It offers an innovative defence of scepticism based on a critical and radical analysis of the concepts of knowledge and truth. Metaphysical and transcendental traditions are deconstructed, mainly in relation to the paradoxes of so-called realism and idealism, which are the consequence of dependence on an archaic substance theory. Moreover, the book proposes a certain form of philosophising in spite of everything, i.e. within a sceptical approach. The critique of ethics leads to an a-ethical concept of the will and the values of life. This book is a defence of scepticism, based on a critical analysis of the concept of knowledge. The metaphysics of substance and its modern and contemporary consequences are analyzed, mostly the transcendental tradition. Finally, a sceptical approach is proposed, leading to an a-ethical concept of the will and the values of life.