A/HRC/23/47 where LARs cannot reliably distinguish between combatants or other belligerents and civilians, their use will be unlawful. 67. There are several factors that will likely impede the ability of LARs to operate according to these rules in this regard, including the technological inadequacy of existing sensors,42 a robot‟s inability to understand context, and the difficulty of applying of IHL language in defining non-combatant status in practice, which must be translated into a computer programme. 43 It would be difficult for robots to establish, for example, whether someone is wounded and hors de combat, and also whether soldiers are in the process of surrendering. 68. The current proliferation of asymmetric warfare and non-international armed conflicts, also in urban environments, presents a significant barrier to the capabilities of LARs to distinguish civilians from otherwise lawful targets. This is especially so where complicated assessments such as “direct participation in hostilities” have to be made. Experts have noted that for counter-insurgency and unconventional warfare, in which combatants are often only identifiable through the interpretation of conduct, the inability of LARs to interpret intentions and emotions will be a significant obstacle to compliance with the rule of distinction.44 69. Yet humans are not necessarily superior to machines in their ability to distinguish. In some contexts technology can offer increased precision. For example, a soldier who is confronted with a situation where it is not clear whether an unknown person is a combatant or a civilian may out of the instinct of survival shoot immediately, whereas a robot may utilize different tactics to go closer and, only when fired upon, return fire. Robots can thus act “conservatively”45 and “can shoot second.”46 Moreover, in some cases the powerful sensors and processing powers of LARs can potentially lift the “fog of war” for human soldiers and prevent the kinds of mistakes that often lead to atrocities during armed conflict, and thus save lives.47 70. The rule of proportionality requires that the expected harm to civilians be measured, prior to the attack, against the anticipated military advantage to be gained from the operation.48 This rule, described as “one of the most complex rules of international humanitarian law,”49 is largely dependent on subjective estimates of value and contextspecificity. 71. Whether an attack complies with the rule of proportionality needs to be assessed on a case-by-case basis, depending on the specific context and considering the totality of the circumstances.50 The value of a target, which determines the level of permissible collateral damage, is constantly changing and depends on the moment in the conflict. Concerns have been expressed that the open-endedness of the rule of proportionality combined with the complexity of circumstances may result in undesired and unexpected behaviour by LARs, with deadly consequences.51 The inability to “frame” and contextualize the environment 42 43 44 45 46 47 48 49 50 51 Noel Sharkey “Grounds for Discrimination: Autonomous Robot Weapons” RUSI Defence Systems (Oct 2008) pp. 88-89, available from http://rusi.org/downloads/assets/23sharkey.pdf Peter Asaro “On Banning Autonomous Weapon Systems: Human Rights, Automation, and the Dehumanisation of Lethal Decision-making” p. 94, International Review of the Red Cross (forthcoming 2013) p. 11. Human Rights Watch (see note 7 above), p. 31. Marchant (see note 26 above), p. 280. Singer (see note 3 above), p. 398. Ibid. Protocol I additional to the Geneva Conventions, 1977, art. 51 (5) (b). Human Rights Watch (see note 7 above), p. 32. Lin (see note 34 above), p. 57. Noel Sharkey, “Automated Killers and the Computing Profession” Computer, Vol. 40 (2007), p. 122. 13