The Proof for a Necessary Existent in the Summa Halensis

Abstract

: Since the late medieval period, Anselm of Canterbury has been heralded in the West as the first proponent of the so-called ontological argument for God ’ s existence. This kind of argument purports to provide proof for the reality of God, which is derived from the very definition of God as the supreme being. Although Anselm ’ s work has garnered considerable attention in the late medieval and modern periods, it was largely neglected in the century between his death and the first years of the University of Paris in the early 13th century. A few other precedents notwithstanding, Alexander of Hales and the authors of the Summa Halensis were the first extensively to appropriate and popularise the work of Anselm, not least, the famous argument which can be found in chapters 2 – 3 of his Proslogion. As I will demonstrate in this chapter, however, the Summa ’ s version of Anselm ’ s argument represents a significant development beyond Anselm ’ s own iteration. Through an assessment of Anselm ’ s argument on its own terms and a study of the Summa ’ s presentation of the argument in relation to its sources — above all, Richard of St Victor and Avicenna — I will argue that early Franciscans rather than Anselm are responsible for developing the version of the ontological argument that has been associated in some form with Anselm ’ s legacy to this day. Since the late medieval period, Anselm of Canterbury has been heralded in the West as the first proponent of the so-called ontological argument for God ’ s existence. This kind of argument purports to provide proof for the reality of God, which is derived from the very definition of God as the supreme being. As such a being, ontological arguments presume, God must possess all perfections — including the perfection of existence. Thus, one need only think about what he is to know that he exists. In that sense, ontological arguments are purely rational: they have no other source than human reason. Over the centuries, philosophers have formulated many different versions of this basic argument; however, most of them are framed with reference to a broader tradition of thought that began with Anselm.¹