Sergeant, John (1623–1704)

John Sergeant was the last of the Blackloists – the faction of English Catholics who followed the thought of Thomas White in the middle decades of the seventeenth century. As such his major philosophical concern was with a refutation of scepticism, and to that end he adopted a synthesis of Aristotelianism and aspects of the new philosophy. Sergeant is now best remembered as the main Catholic protagonist in the theological ‘rule of faith’ debates, when he engaged with such eminent Anglicans as Tillotson and Stillingfleet to argue the cause of religious certainty, attainable only through Catholic tradition. Turning later to the need for certainty in philosophy and science, he formulated his own ‘solid philosophy’: within an essentially Aristotelian framework, he incorporated aspects of the new thought that had been earlier adopted by Thomas White and Kenelm Digby.