Drawing the line between reasonable and unreasonable risk imposition requires appealing to concepts such as probabilities and the size of benefits obtained by taking a risk.

The problem of dealing with risks in deontological theories is similar to the corresponding problem in rights-based theories. The duty not to harm other people can be extended to a duty not to perform actions that increase their risk of being harmed. However, society as we know it is not possible without exceptions to this rule. The determination of criteria for such exceptions is problematic in the same way as for rights-based theories. All reasonable systems of moral obligations will contain a