Critique, skepticism, conflict, incompleteness, nothingness, irrational abyss, evil, and even genocide… That is what German idealism is also about. Trying to chart human reason as an architectural system, Kant, Fichte, Hegel, and Schelling uncovered that the most significant problems lie beneath the ground, in the foundations. Can reason survive the discovery of what lies at its depths? And should it? This book ventures into these foundations, addressing the keen philosophical innovations of German idealists. Through comparative and development studies, it presents fresh interpretations of how these leading thinkers reconstructed reason on unexplored territories. The greatest hazard was triggering an enduring inversion of values.