This book brings together the text of four lectures given at the university in Dublin in 1950. The title does not adequately address all the ViaMichelin sections, the most overflowing onto more philosophical than scientific considerations. For Schrödinger, science should not fall in "barbarism of specialization", but help to better understand our place in the universe, going hand in hand with linvestigation philosophical and epistemological reflection. I knew only the man of science, famous for having formulated the equation in 1926 that bears his name, and his cat analogy half dead half alive, dincertitude illustration of the principle in quantum physics. I discover in this first reading the thinker, scholar, deep and light. The first pages show the ways in which quantum physics revolutionized our conceptions of the universe. While classical physics is deterministic maintaining a separation between subject / object and is suitable for a description of the object in itself properties of quantum mechanics, on the contrary indeterminist, emphasizing the interaction between subject / object, and thus the impossibility of representation spatio-temporal phenomena. From this dindétermination principle, Schrödinger starts a light reflection on its implications for our conception of free will, saying in passing that this is not a new problem since Democritus, Epicurus and St. Augustine had already lintuition. One can easily understand his demonstrations such as those relating to the concept of continuity, or on that of the substitution of the form to the substance, even if we do not quite understand the mathematical equations to supporting.