 Ross’s five basic principles contribute to explaining other, non-basic moral considerations. The duty not to lie has two sources. Ross thinks you ought not lie because, in line with the duty of non-maleficence, to ‘tell lies is prima facie to do a positive injury to another person’ (RG 55) and because, in line with the duty of fidelity, when you enter into a conversation there is an implicit promise or understanding ‘language shall be used to convey the real opinions of . . . speakers’ (RG 54; also 21; FE 97). The obligation to obey the laws of one’s country is explained by the obligations of gratitude, fidelity and beneficence (RG 27). If one has benefitted from the laws of one’s country one ought to obey those out of gratitude for the benefit; if one has remained in a country in which one knows one is expected to obey the laws and one has relied on them for benefit, one has (at least implicitly) promised to obey them and should do so for that reason; if one’s country’s laws work to promote the general good, one ought to obey them as part of promoting general good (RG 27–28).