  This last claim is denied by those who believe that the offence/defence distinction is substantive. These writers accept that offences and defences are governed by different procedural rules. Their claim is that the distinction between offences and defences explains why those rules differ. Perhaps the most well-known version of this view runs as follows. Offence elements are individually necessary, and jointly sufficient, to describe an act that there is general reason not to perform. Defence elements block the transition from the existence of that reason to the conclusion that \(D\) ought to be convicted of a crime. On this view, whether we should think of the absence of consent as an element of the offence of sexual assault, depends on whether we think that there is a general reason not to have consensual sex with others. If there is no such reason, the absence of consent is necessary to give us an act we have general reason not to perform. So it is an element of the offence of sexual assault. If, on the other hand, there is a general reason not to have consensual sex, consent is properly thought of as a defence to sexual assault (Campbell 1987; Gardner 2007, 144–149).