The Place of the Proof for God’s Existence in the Summa Theologiae of Thomas Aquinas

THE PLACE OF THE PROOF FOR GOD'S EXISTENCE IN THE SUMMA THEOLOGIAE OF THOMAS AQUINAS THE PRESENT ARCHBISHOP of Canterbury, the Most Reverend Robert Runcie, in an interview at the time of his election, said: "Someone once preached a sermon in which he tackled the question 'How do you know there is a God?' In essence his answer was, as it was certainly the answer for me: we know there is a God because we've been told-that is the traditional element in religion ... a distilling of people's experience which has been passed on" (The Observer, Sunday ~O January, 1980, section 3, p. 33). Thomas Aquinas, writing between rn66 and 1268,1 in the initial questions of his Summa Theologiae, asks whether God exists. He raises two objections to God's existence; first, the presence of evil in the world, and second, that nature, together with human will and reason, is sufficient to explain what we experience, but then, on the other side, he cites God himself. "But, on the contrary, there is what is said in Exodus 3 by the person of God 'I am who I am' ".2 Thus, if we pass over the not unimportant difference that Robert Runcie speaks of a tradition distilling "people's experience'', while Aquinas starts from what God in his own person says, both begin treating God's existence from what we have been told. Faith seeks understanding but certainly need not commence with philosophi1 J. A. Weisheipl, Friar Thomas d'Aquino: His Life, Thought and Works (Oxford, 1975)' p. 361. 2 Sitmma Theologiae, ed. altera emendata, ed. Commissio Piana (Ottawa, 1958), I,~,3; hereafter abbreviated ST. For the Summa contra Gentiles I have used the the Leonine Opera Omnia Vol. XIII-XV (Romae, 1918-1980) abbreviated ScG. For the theological significance of Thomas's beginning with Exodus 3.14 see E. zum BI"Unn, "La 'metaphysique de l'Exode' selon Thomas d'Aquin ", Dieu et l'Etre: Exegeses d'Exode 3,14 et de Coran 20,11-24, ed. Centre d'Etudes des religions du livre, CNRS, Etudes augustiniennes (Paris, 1978), pp. ~45-~69, esp. p. ~67. 370 THE PLACE OF THE PROOF FOR Gon's EXISTENCE 871 cal reason.3 So Aquinas teaches that theology or sacred doctrine is a knowledge which begins from principles made evident to a higher form of cognition, namely, that possessed by God and the blessed.4 The knowledge from which theology starts is God's own simple knowledge of himself, and all else in himself,5 communicated to the Prophets and Apostles who wrote the canonical books,0 handed on to us through that Scripture, and summed up in the articles of the faith.7 It is because sacred theology begins with God's own self-revelation grasped by faith that it has a shape and order distinct from natural theology, the theology which is a part of philosophy.8 Sacred doctrine is able to start with God. After considering God in himself, it shows how creatures come out from him and how he then brings them back into union with himself.9 Philo· sophical reason starts rather with creatures and climbs by a long and difficult ladder to knowledge of God.10 The order of sacred doctrine determines the order of matters in the tripartite structure of the Summa Theologiae. It begins with God and treats him and his creative work in the First Part. The a ST 1,1,8 ad 2; 1,2,2 ad 1. Theology begins with the unity of God, not because this is comprehensible, see In librum Beati Dionysii de Divinis Nominibus Expositio , ed. C. Pera (Taurini-Romae, 1950), proemium and Il,ii,143, but because the one is by nature principle (ibid., Il,ii,135 and 148; XIll,ii,981) and my article " The De Trinitate of St. Boethius and the Structure of the Summa Theologiae of St. Thomas Aquinas", Atti del Congresso Internazionale di Studi Boeziani, Pavia, 5-8 ottobre, 1980, ed. L. Obertello (Romae, 1981), pp. 367-375. 4 ST 1,1,2. 5 In de div. nom., 1,1,13; ST l,1,2 ad 2, ST 1,1.4...