Chisholm sketched a situation in which a person, (we can call him ‘Smith’), had (a) an obligation to go to the aid of his neighbor, (we can call him ‘Jones’). Assuming that it would be best to notify Jones beforehand, Chisholm imagined that (b) Smith also had a conditional obligation to notify Jones in advance if he was going to come to his aid. On the other hand, (c) if he was going to fail to come to Jones’s aid, then Smith’s obligation would be to avoid telling him that he was coming to his aid. Finally, Chisholm assumed that (d) Smith was going to fail to come to Jones’s aid.