L’esistenza dell’assoluto. Sulla Dottrina della scienza 1805 - The Doctrine of Science of 1805, which Fichte developed at the University of Erlangen, is a philosophical reflection displaying great theoretical vigour. It can be seen as consisting of two parts: the theory of existence or of knowledge and the theory of form or of objectivity. In this work Fichte makes a criticism of certain concepts of Schelling, as expounded in Philosophy and Religion (1804), concerning the relationship between thought and life, between subjectivity and absolute reason (or essence) and between form and being, as well as the idea of nothingness. Considered here to be the central concept in Fichte’s doctrine is the idea of knowledge (Wissen) or of thought as absolute existence and as the existence of the absolute.