Those who cannot conceive of change in the Church’s attitude to contraception rely, according to Mr Dummett’s February article in New Blackfriars, on two main lines of argument. One is described as the ‘Where do we draw the line ?’ form of argument—if contraception is lawful, then perhaps so also are sterilization, abortion, sodomy, masturbation, fornication or even adultery. The other argument is also of the same form (though Mr Dummett does not so describe it) for it asks ‘Where do we draw the line?’—if the Church’s moral teaching is untrustworthy here, how can we be sure that it is to be trusted on any other subject ?

Both arguments, it seems to me, presuppose the asking and answering of a more fundamental question: to what extent can lines be drawn at all when moral issues are at stake ? The encyclical takes its stand on ‘what is called the “objective” moral order laid down by God’, and reminds parents that ‘they are not free to define an honest course of action in any way whatsoever that they choose (modo omino proprio ac libero), since they are bound, on the contrary, to act in accordance with the plan of the divine creator’ (para. 10). This again, it seems to me, presupposes a fundamental question: what sort of ‘objectivity’ is here being referred to, in what sense has God indeed got a ‘plan’ ?