What is Morin's conception of science and reality? What does Morin mean by complex thinking, or, to put it metaphorically, if Edgar Morin questions the structure of the edifice of classical science, what is the structure he proposes and on what does he base it? In order to answer these questions, the aim was to analyse and understand hermeneutically and critically the two aspects that are considered most fundamental in relation to Edgar Morin's complex thought, namely the epistemological aspect and the ontological aspect. In other words, the present work, more than showing some strengths, seeks to demonstrate the weaknesses of the author of the Method in the two points mentioned above that are the ones that order the exposition; where the approaches referred to epistemology are found in what Morin calls the knowledge of knowledge, while the ontology of complexity is clearly expressed, in his theme on the noosphere.