Throughout the seventies, there has been a revival of systematic philosophy usually and of ontology specifically. whilst, in particular in Anglo-Saxon pondering, systematic philosophy interacted very creatively with the background of medieval philosophy. it kind of feels to us that the paintings of John Duns Scotus (1266-1308) might considerably profit those boost ments. not just this, yet his works cries out to be constructed around the complete spectrum of theology -that technology which, within the heart a long time, governed all others ('regina scientiarum'). This booklet is the end result of numerous years of scholarship and buddy send in which, guided through Dr. A. Vos, we have now studied the paintings of Scotus. Our examine staff is attached to the Theological school of Utrecht and to the Dutch Franciscan examine Centre (Stichting Francis caans Studiecentrum). This research offers a translation and observation of Lectura I 39, which, in our view, is noteable as one of many key texts within the historical past of systematic theology and philosophy. during this e-book now we have used professional language and argumentation, yet whilst have taken pains to make it priceless to a circle of in terested readers wider than just that of these well-versed in medieval scholasticism. during this means, we are hoping to provide the tricky yet instruc tive paintings of the 'subtle grasp' ('doctor subtilis') in the sort of method as to make it beautiful to different students and scholars in theology and philoso phy.