No More Humans? Enhanced Soldiers as a Weapon, Means or Method of Warfare

By: Thibault Moulin

Doctrinal Background

Could a soldier be considered as a thing? At first sight, this idea might sound questionable–perhaps shocking. However, this is precisely one of the questions raised by human enhancement technologies, which started to make its own way in scholarship.

For instance, Chircop and Livoja suggest that a pharmaceutically-enhanced warfighter ‘does not become a mere instrument’ or a ‘weapon’, ‘as long as a warfighter possesses human agency [...] the ability to exercise free will’.[1] However, should this ‘human agency’ be ‘erased’, ‘turning the warfighter into a mere automaton or a remotely controlled biological avatar’, it would ‘be possible to speak of warfighters as weapons’.[2] They also think that ‘a robotically enhanced warfighter will constitute a means of warfare as soon as the warfighter is, to any extent, integrated with a weapon’.[3] Consequently, ‘[w]here the BMI [Brain-Machine Interfaces] does not use external sensors to record neural activity but relies on implanted electrodes, the integration of the warfighter with the weapon system is such that it is difficult to separate the two. In such circumstances, the warfighter becomes part of the weapon system, and thus a component of a means of warfare’.[4] However, the techniques used by BMIs are more diverse than the ‘recording’ of ‘neural activity’ through ‘external sensors’ (non-invasive) or ‘implanted electrodes’ (invasive). As a matter of fact, they also involve partially-invasive technologies, as well as neurostimulation. The variety of technologies and their potential for military applications need to be taken into account, to determine whether a soldier might be considered a ‘mean’ of warfare.

After having mentioned that ‘autonomous robots are clearly regulatable weapons’, Lin, Mehlman and Abney tackle the situation of a cyborg, ‘part-human, part-machine’.[5] They however mention that, ‘[i]f we want to say that robots are weapons but humans are not, then we would be challenged to identify the point on that spectrum at which the human becomes a robot or a weapon’.[6] They then suggest a ‘simpler solution’: ‘to say that humans are weapons’.[7] Harrison Dinniss and Kleffner consider ‘that the enhanced human soldier, per se, is not to be considered a weapon, because it is not the person that constitutes the offensive capability that can be applied to military objectives or enemy combatants’.[8] For the time being, they think that ‘a distinction between the human, on the one hand, and the enhancement technology, on the other, remains possible since the use of the technology does not convert the human into an object that could be considered a weapon’.[9] Noll affirm that, ‘[t]o the extent that neurotechnology informs future weapons systems, states are under an obligation to consider how the resulting weapons system would relate to IHL obligations’.[10] According to Beard, Galliott and Lynch, ‘[i]f a weapon is deployed in violation of international law, intuition suggests that the person wielding it will be held responsible’.[11] However, ‘this analogy may not extend to enhanced warfighters, who are simultaneously weapon and wielder’.[12] These scholars thus go one step further: they contemplate the possibility for a human being (a warfighter) to be considered as a weapon.


This project proposes to revisit these questions, from the perspective of article 36 of the Protocol Additional I to the Geneva Conventions, and with a specific focus on brain-machine interfaces. According to article 36, ‘[i]n the study, development, acquisition or adoption of a new weapon, means or method of warfare, a High Contracting Party is under an obligation to determine whether its employment would, in some or all circumstances, be prohibited by this Protocol or by any other rule of international law applicable to the High Contracting Party’.

Structure and Methods

In its introduction, this paper will identify the different types of BCIs and their functioning. The concept of this technology is the following: electrodes are either placed on the head (non-invasive), on the skull (partially invasive), or arrays implanted in the brain (invasive). Then, this device ‘translates neuronal information into commands capable of controlling external software or hardware such as a computer or robotic arm’.[13] The status of their military applications will also be investigated, as well as the projects that are supposed to be developed in the future. For instance, in September 2018, DARPA ‘confirmed that an individual equipped with an experimental brain-computer interface […] was able to successfully command and control multiple simulated jet aircraft’.[14] To proceed, the research will focus on medical and bioethics reviews, official publications, as well as a sample of concrete clinical trials.

It is then necessary to study whether a qualification of either the enhancing technology or the enhanced soldier as ‘weapons’ (I) ‘means’ (II) or ‘methods’ of warfare (III) is possible.

  1. A first challenge is a literal one: no consensus exists regarding the definition of ‘weapon’ and ‘means’ of warfare. Most dictionary definitions point at the fact that a ‘weapon’ is an instrument used to cause destruction, injure or kill someone. However, states have traditionally avoided to define this notion, and prefer to define specific types of weapons (biological, chemical, nuclear etc). Germany is among the few exceptions, as ‘weapons’ are defined as ‘instruments that are intended or suitable to kill or injure persons, eliminate or decrease offensive or defensive capacity, and/or to destroy or damage objects’.[15] As to the USA, ‘weapon’ may be understood as ‘[a] device designed to kill, injure, disable or temporarily incapacitate people or destroy, damage, disable or temporarily incapacitate property or materiel’.[16] This mutism disappears with the ‘means’ of warfare, which often find a state definition. However, another problem here is that these definitions are more or less large. Supporters of a wide definition include the USA, Germany and the ICRC. ‘Means’ is defined by the USA as ‘[a] combination of one or more weapons with all related equipment, materials, services, personnel, and means of delivery and deployment (if applicable) required for self-sufficiency’.[17] Germany define them as ‘instruments which, without being weapons themselves, have an impact on particular offensive or defensive capacities’.[18] The ICRC considers that they ‘designate the tools of war’.[19] A more restrictive definition is proposed by the French, British and Australian armies. France suggests that ‘means of warfare refer to weapon, projectiles and substances used’,[20] while the UK considers ‘means’ and ‘weapons’ as similar terms.[21] When considering ‘means of armed conflict at sea’, Australia only evokes ‘[m]ines’, ‘[t]orpedoes’, ‘[m]issiles and other projectiles’.[22] ‘Methods of warfare’ is a less divisive notion. The USA has suggested that the term ‘method of warfare has referred to how warfare is conducted […]’.[23] This is also the view of the ICRC, which considers they are ‘the ways in which they [tools of war] are used’.[24] France affirms that they refer to ‘strategies or tactics’, and the UK, to ‘tactics’. Germany define them as ‘the planification, concepts or doctrines for military procedures that are conceived to affect the military operations and capacities of the enemy, or to protect one's own military operations and capacities’.[25] In each part of this paper, it will thus be necessary to study official state publications, to determine whether a common understanding of ‘weapons’ and ‘means’ of warfare might be identified, or whether states actually have a large latitude in this process. Depending on the outcome, this field could be characterized by a patchwork of divergent national understandings and regulations.
  2. The case of enhancing technologies (BMIs) and enhanced soldiers (warfighters equipped with BMIs) will be evaluated in the light of this previous research. The case of enhancing technologies calls for a study of the nature of BMIs themselves, their effects. It is indeed conceivable that, for the time being, they are merely an intermediary between a person and a weapon, such as an airplane or a drone.[26] The case of enhanced soldiers will then call for a study of the degree of integration of the soldier with the BCIs, his connection with this equipment. A global picture of the way new weapons (drones, cyber-tools etc) have traditionally been tackled will also be displayed. It will also be determined whether states contemplate submitting BMIs to weapon review. Israel has for instance expressed this possibility.[27]

[1] Luke Chircop and Rain Livoja, ‘Are Enhanced Warfighters Weapons, Means, or Methods of Warfare’ (2018) 94 ILS 161, 177.

[2] Ibid.

[3] Ibid 180.

[4] Ibid.

[5] Patrick Lin, Maxwell Mehlman and Keith Abney, ‘Enhanced Warfighters: Risk, Ethics, and Policy’ (2013) 29.

[6] Ibid.

[7] Ibid 29-30.

[8] Heather Harrison Dinniss and Jann Kleffner, ‘Soldier 2.0: Military Human Enhancement and International Law’ (2016) 92 ILS 432, 438.

[9] Ibid.

[10] Gregor Noll, ‘Weaponising neurotechnology: international humanitarian law and the loss of language’ (2014) 2(2) London Review of International Law 201, 211.

[11] Matthew Beard, Jai Galliott and Sandra Lynch, 'Soldier Enhancement: Ethical Risks and Opportunities' (2016) 13(1) Australian Army Journal 5, 15.

[12] Ibid.

[13] ‘Brain-Machine Interface (Nature) <>

[14] William Kucinski, 'DARPA subject controls multiple simulated aircraft with brain-computer interface' (SAE, 12 September 2018) <

[15] Bundesministerium für Verteidigung, Prüfung neuer Waffen, Mittel und Methoden der Kriegführung (2016) 37, [301].

[16] Department of the Air Force, ‘The Law of War’ (03.08.2018) Air Force Instructions 51-401, 13 <

[17] DOD, ‘Dictionary of Military and Associated Terms’ (2018 252 <>

[18] Bundesministerium für Verteidigung, Prüfung neuer Waffen, Mittel und Methoden der Kriegführung (2016) 37, [301].

[19] ICRC, ‘A Guide to the Legal Review of New Weapons, Means and Methods of Warfare: Measures to Implement Article 36 of Additional Protocol I of 1977’ (2006) 932.

[20] Ministère de la Défense, Manuel du droit des conflits armés (Ministère de la Défense 2012) 64.

[21] MOD, The Joint Service Manual of the Law of Armed Conflict (DSDC(L) 2004) 82 [5.32.4].

[22] Commonwealth of Australia, Law of armed conflict (Defence Publishing Service 2006) 6-7.

[24] ICRC, ‘A Guide to the Legal Review of New Weapons, Means and Methods of Warfare: Measures to Implement Article 36 of Additional Protocol I of 1977’ (2006) 932.

[25] Bundesministerium für Verteidigung, Prüfung neuer Waffen, Mittel und Methoden der Kriegführung (2016) 37, [301].

[26] William Boothby, New Technologies and the Law in War and Peace (CUP 2018) 384.

[27] ‘Statement on Lethal Autonomous Weapons Systems (LAWS)’ (2016) <$file/2016_LAWS_+MX_ChallengestoIHL_Statements_Israel.pdf>