This study compares Martin Heidegger's concept of "possibility" as presented in Being and Time with the philosophical framework of Emanuel Rádl, who asserts that "what ought to be" is the author of "what is." While Heidegger famously states that possibility stands higher than reality, Rádl identifies ultimate truth as a challenge and a moral duty that dictates our actions in the world. The text explores the interpretation of the Aristotelian term dynamis, arguing that Rádl's conception of truth as a challenge possesses a dynamic quality distinct from the classical Greek understanding of cause. It suggests that Rádl may have captured the essence of possibility more profoundly than Heidegger by framing it not merely as an ontological category, but as an active ethical imperative. By connecting truth with obligation, Rádl transforms abstract possibility into a concrete existential task. This comparison highlights the tension between ontological potentiality and moral teleology, offering a unique perspective on how ideals shape our understanding of existence and reality.