 Hence, a right not to be risk-exposed will have to be defeasible so that it can be overridden in some (but not necessarily all) cases when the increase in probability is small. However, it remains to find a credible criterion for when it should be overridden. As Nozick observed, a probability limit is not credible in “a tradition which holds that stealing a penny or a pin or anything from someone violates his rights. That tradition does not select a threshold measure of harm as a lower limit, in the case of harms certain to occur” (Nozick 1974, 75).