Abstract
Natural sciences and natural philosophy of the Jesuits are based on theology. At least the concept of God is an integral part of their theoretical structure. Examples are taken from Rudjer Boskovic, Honoré Fabri and Nicolaus Cabeus. In fact, the Jesuits, e.g. Theophil Raynaud, dealt with natural theology as the spiritual foundation of knowledge independent of revelation. But natural theology, as in Raimundus Sabundus, has an anthropocentric and hence moral dimension: it links knowledge with religion. ‘Ignatius of Loyola influenced decisively the Jesuits’ concept of science and its relationship to religion through his Spiritual Exercises in which meditation and religious practice are developed into a technique and a scientific approach to faith.