 There are at least two good descriptive reasons to be sceptical about both the belief- and the consent-based theories of customary international law. First, they cannot explain why newly independent states are bound by rules of custom in respect of which they never had an opportunity to give consent or time to form beliefs (Hart 1961 [2012: 226]). Secondly, neither the consent-based nor the belief-based account of customary international law can adequately explain change in customary rules. Under the consent-based theory, the replacement of a rule of custom with a contrary one would be explained as a consequence of states withdrawing their consent from, and acting in breach of, the prior rule. Under the belief-based approach, a change in custom would be explained by error or insincerity on the part of states, either acting on the erroneous belief that a particular rule was one of customary international law or lying about their belief.