This chapter focuses on the Lacanian idea of an ‘inaugural trauma’ that is the result of the human being’s entry into language and which constitutes the human subject itself. The key arguments revolve around Lacan’s proposition in Science and Truth that the subject of psychoanalysis is also the subject of modern science. In order to explore the logic of Lacan’s argument in this respect the chapter examines in some detail the idea of the Cartesian subject in relation to modern science and also the work of Alexandre Koyré, whose writings were very influential upon Lacan in his understanding of the development of science since the late fifteenth century. A particularly key idea referred to in the chapter is Lacan’s use of the concept of suture and especially Miller’s treatment which draws extensively on the ideas of the mathematician Gottlob Frege. Lacan’s idea of truth as cause is also discussed, with a particular focus on his use of Aristotle’s concepts of tuché and automaton in Seminar XI, which links closely to his arguments regarding the Real and trauma.