This paper is founded on a close reading of Kant’s Opus Postumum in order both to explore the essential motivation that drove Kant to write a last comprehensive magnum opus and, by doing so, to show the essential link between his aesthetics and the idea of Übergang, the title of this last work. For this work contains not only his dynamical theory of matter defining motion as preliminary to the notions of space and time, and the advanced version of his philosophy of natural science, but also his arguments for the phenomenal validity of the metaphysical foundations, his teachings on the aesthetic human faculties of judgment and Anschauung, and the discernment of the transcendental philosophy from Platonic idealism carrying it to a cosmological level, i.e. Kant’s insertion of the concept of cosmotheoros. Since the process of transition is an aesthetic process based on human senses, intuitions and judgments, the argument will follow that in order to explicate Übergang, we need to reconcile cosmology, as the oldest branch of philosophy dealing with the interactions between the cosmic forces and the ways they affect human life, with aesthetics, as the youngest branch of philosophy dealing with how we sense, intuit and judge the form and motion of matter. Therefore, in the last analysis, Übergang becomes rather a cosmologic-aesthetic principle similar to the Heraclitean logos. Another building block of the paper is the fruitful comparison between the Kantian sublime and Nietzschean Dionysian, which are going to be construed as the aesthetic theories on human understanding representing the transition from nature to art. For they are not only conceptual – aesthetic but also dynamic – cosmological theories due to their reference both to nature and to human nature.