In this article, we examine Quentin Meillassoux’s concept of speculation. Starting from a characterization provided by Graham Harman, which we consider to be misleading, we will first seek to clarify two key aspects of Meillassoux’s speculation, namely non-metaphysicality and factiality. In doing so, we will demonstrate a tension between systematicity and exposition within speculative materialism. Finally, we will refer to Meillassoux’s theory of faculties and to his distinction between two concepts of absolute in order to explain the difference between philosophical speculation and the trace left by this speculation in natural sciences.Je dois donner un sens à ce qui n’en a pas: l’être à la fin nous est donné comme impossible!(Georges Bataille, Méthode de méditation)