In this article, we examine the process philosophy of Alfred North Whitehead through its key concepts. While several of the authors and approaches informed and inspired by Whitehead have been much discussed in Finland, so far his own work has remained largely unexplored. We propose that the basic dynamics of Whitehead’s metaphysics are organised around two axes. On the one hand, his thought centres on the processes of becoming and perishing between actual entities and eternal objects. For Whitehead, the world is a process: he regards process as the most fundamental, pervasive, and elementary feature of reality. However, what distinguishes Whitehead’s process ontology from various other philosophies of becoming is its ‘occasionalist’ emphasis. In contrast to Bergson and Deleuze, for instance, he does not view process as the perpetual reproduction, change and flux of life, but as the becoming of punctual, atomistic actual occasions. For him, there is no continuity of becoming, but only becoming of continuity. On the other hand, Whiteheadian philosophy focuses on the relation of subjects and the world in experience. According to Whitehead, subjects do not pre-exist their experiences and the world is no passive object external to experience, but both subject and the world constituted in and by experience. Experience presents a prerequisite for the becoming of any object: ultimately, there is nothing apart from experience, and things are always experienced – they become – in some specific way.