It is the contention of Professor Geach in ‘Omnipotence’, Philosophy 48 (1973) 7-20, called GP in what follows, that ‘no graspable sense has ever been given to this sentence [‘God can do everything’] that did not lead to self-contradiction or at least to conclusions manifestly untenable from a Christian point of view’ (GP 7-8). In the still more recent ‘An irrelevance of omnipotence’, Philosophy 48 (1973) 327-33, called GIOP in what follows, he continues to maintain a thesis of that kind: ‘any thesis that gives a plausible interpretation of the sentence ‘God can do everything’ is a thesis involving both inherent logical difficulties and conclusions hard to reconcile with traditional Christian belief’ (GIOP 327), and ‘sense is not to be made of “God can do everything” ‘ (GIOP 332). His contention, as the present paper will show, will not in fact survive straightforwardly logical criticism owing nothing essential to any arcane points of detail peculiar to philosophical theology.

Reasonably dismissing some other possible ways of understanding ‘God can do everything’—which should rather be put as ‘There is nothing that God cannot do’—Professor Geach brings his main batteries against a position held by many catholic theologians, St Thomas Aquinas among them. According to that position ‘ “God can do so- and-so” is true just if “God does so-and-so” is logically consistent— there may be consistently describable feats which it would involve contradiction to suppose done by God’ (G P 9’s italics). In view of that restriction which G P rightly emphasises, Aquinas advanced the thesis