Philosophy becomes speculative when it raises questions about the ultimate nature of being and thought. What does it mean to be? What does it mean to think? How are being and thought related? What does it mean to ask these questions? These questions have occupied a central place in philosophy throughout history, but have led a shadow existence in twentieth-century thought, which has cut the tie between reason and these fundamental questions, leaving the questions in the twilight, and reason instrumentalised. (...) A.N. Whitehead (1861-1947), one of the founders of analytic philosophy and co-author (with Bertrand Russell) of Principia Mathematica, is one of the few contemporary thinkers to have developed an explicit speculative philosophy. Unsurprisingly, his philosophy has played a marginal role in academic debates. In this study, the methodological foundation of Whitehead’s speculative thought is reconstructed. On the basis of a systematic and historical examination of the nature of the question of being, Whiteheads ontology of the event as the passage into novelty emerges in its full scope, allowing the reader to understand why and to what extent Whitehead has walked a different path than other contemporary thinkers. His philosophy contains a conception of reason that is not alien to newness and creativity while being more than procedural or pragmatic, and a mode of understanding existence that brings out the acuteness of freedom, value and legitimacy, as well as the unity of things, of thought and nature. In order to show what is really happening in this philosophy, the received interpretation of Whitehead’s ontology is radically dismantled. The central thought, that to be means to happen, is explained in a process of reiteration and gradual clarification, examining traditional philosophical problems in metaphysics and epistemology (on topics like: nature and matter, knowledge, categorical structure, freedom and necessity, truth and meaning, modality) from its perspective. What emerges is a philosophy in which the temporality of being, when taken seriously, changes the status of familiar problems and dualisms and offers possibilities for thought, which previously did not exist. Whitehead “hears” the classical questions of philosophy in a new way. Beyond the trenches of twentieth-century philosophy, Whitehead’s speculative thinking contains many elements that will be of value to those studying the foundations of thought today and looking for new directions. In a time when the dualism of nature and man is maintained cynically in our economies and dismantled, but only in a biologistic fashion and therefore only seemingly, as a cover-up, in science and philosophy, Whitehead’s new and creative way of hearing, and answering, old questions about ultimate concerns, when understood properly, is more up to date than ever before. (shrink)