Abstract

In the Summa Theologiae ‘simplicity’ is treated as pre–eminent among the terms which may properly be used to describe the divine nature. The Question in which Thomas demonstrates that God must be ‘totally and in every way simple’ (1.3.7) immediately follows the five proofs of God's existence, preceding the treatment of His other perfections, and being frequently used as the basis for proving them. Then in Question 13 ‘univocal predication' is held to be ‘impossible between God and creatures’ so that at best ‘some things are said of God and creatures analogically’ because of the necessity of using ‘various and multiplied conceptions’ derived from our knowledge of created beings to refer to what in God is simple for ‘the perfections flowing from God to creatures… pre–exist in God unitedly and simply, whereas in creatures they are received divided and multiplied’ (1.13.5). In line with this, in the De Potentia Dei the treatment of analogical predication is integrated into that of ‘the Simplicity of the Divine Essence’ (Q 7). Moreover, it lies at the root of Thomas's rejection of any possibility of a Trinitarian natural theology such as, for instance, St Anselm or Richard of St Victor had attempted to develop, on the grounds that ‘it is impossible to attain to the knowledge of the Trinity by natural reason’ since ‘we can know what belongs to the unity of the essence, but not what belongs to the distinction of the persons’ (1.32.1). Even modern minds sympathetic to Thomas have clearly found it difficult to understand his concern for the divine simplicity: in his Aquinas Lecture Plantinga speaks for many in stating that it is ‘a mysterious doctrine’ which is ‘exceedingly hard to grasp or construe’ and ‘it is difficult to see why anyone should be inclined to accept it’. Not surprisingly, therefore, some of the most widely read twentieth–century commentators on Aquinas have paid little attention to it. Increased interest has recently been shown in it, but a number of discussions pay insufficient attention to the historical context out of which Thomas's interest in the doctrine emerged, and consequently tend to misconstrue its nature.