In the mid-seventeenth century a movement of self-styled experimental philosophers emerged in Britain. Originating in the discipline of natural philosophy amongst Fellows of the fledgling Royal Society of London, it soon spread to medicine and by the eighteenth century had impacted moral and political philosophy and even aesthetics. Early modern experimental philosophers gave epistemic priority to observation and experiment over theorising and speculation. They decried the use of hypotheses and system-building without recourse to experiment and, in some quarters, developed a philosophy of experiment. The movement spread to the Netherlands and France in the early eighteenth century and later impacted Germany. Its important role in early modern philosophy was subsequently eclipsed by the widespread adoption of the Kantian historiography of modern philosophy, which emphasised the distinction between rationalism and empiricism and had no place for the historical phenomenon of early modern experimental philosophy. The re-emergence of interest in early modern experimental philosophy roughly coincided with the development of contemporary x-phi and there are some important similarities between the two.