It is important to acknowledge that the theory of Natural Law is defined as absolute (whereby an action is regarded as right or wrong irrespective of differing circumstances or conditions) and deontological (which means that the moral value of an action is judged according to the intention and not the consequences), and is most closely associated with St. Thomas Aquinas, who developed the principles and advances of Aristotle, to produce a moral code (existing within the purpose of nature) which human beings are naturally inclined towards.
In addition, Aquinas maintained that the ‘moral life’ is lived according to reason, which is achieved by following the primary precepts which promote the principles of ‘self-preservation and the preservation of the innocent’, the ‘continuation of the species through reproduction’, the ‘education of children’, to ‘live in society’ and to ‘worship God’. Aquinas also acknowledged four ‘secondary precepts’ (do not murder, do not abort unborn, defend the defenceless and do not commit suicide) which are further rulings that human beings should avoid, as they do not uphold the primary precepts.
In view of this, it is possible to argue that in relation to killing during war, the theory of Natural Law would support military action if it upheld the principle of ‘self-preservation and the preservation of the innocent’, such as countering a real threat by another state or liberating a country where mass atrocities are being committed: the declaration of war against Germany in 1939; the Nazi extermination of the Jews; and the treatment of civilians under the rule of Idi Amin in Rwanda.
However, this raises a further issue, as it is therefore necessary to identify exactly who should be classified as a direct opponent – civilians of the aggressive state, workers in the ammunition factories and power stations – as Natural Law would regard the killing of innocent civilians (and prisoners of war) as unjust and a contradiction of the precepts.
As a result, it is evident that that there are various advantages to applying this theory to practical situations including the fact that it provides justification and support for complex issues such as human rights and equality (whilst condemning actions such as torture, irrespective of the consequences) and appeals to many people’s conviction that right and wrong depend on more than just personal opinion and social convention. However, one may also argue that this ethical theory does not take into account the direct consequences of such action and is also guilty of committing the naturalistic fallacy.
In contrast, it is also significant to make reference to the absolute and deontological ethical theory advocated by Immanuel Kant, who argued (in The Metaphysics of Morals, 1797) that we are able to calculate the moral worth of an action in accordance to the Categorical Imperative – an unconditional command comprising of three principles informing human beings of their duty by directing them to actions which are good in themselves: The Universal Law (for an action to be morally valid, the agent must not carry it out unless he or she believes that, in the same situation, all people should act in the same way); Treat humans as end in themselves (never treat humans as a means to an end); and Act as if you live in a kingdom of ends (act as if you were a law-making member of a kingdom of ends).
Kant also considered that to act morally is to do one’s duty, which involved obeying the moral law, and maintained that human beings seek an ultimate end called the supreme good (the summun bonum) – a state in which human virtue and happiness are united. In the ‘Groundwork for the Metaphysic of Morals, 1785, Kant also declared that the highest form of good is good will, which involved following one’s duty to perform actions that are morally required, without a desire to promote self interest: “..the essence of morality is to be found in the motive from which the act is done alone…A good will is not good because of what it effects or accomplishes…it is good through its willing alone – that is, good in itself.”
From the above information, it is evident that Kant’s theory would condemn any form of killing during war, because it directly undermines the maxim of the categorical imperative, which states that people should never be treated as a ‘means to an end’ – an accepted principle during military conflict: for example, at present, Tony Blair risks the lives of the British armed forces in Iraq in order to overthrow the regime of Saddam Hussein. However, I would question whether Kant’s theory could be applied to such situations (as it appears to contradict itself), as he would also argue that we should always tell the truth (in order to maintain a civilised society) even if that consequently resulted in informing a murderer of the location of his next victim.
It is clear that there are many strengths associated with Kant’s theory, including the fact that it commands respect for human life, provides a set of powerful absolute principles (universal code) that prohibit acts that would be commonly considered wrong (such as murder/killing) and therefore corrects the atrocities that could be justified under a utilitarian approach – the moral value of an action comes from the intrinsic rightness in itself. However, Kant’s theory refuses to allow exceptions to different situations, and it could also be argued that a weakness with the concept of universalisability is the problem of different but similar dilemmas – are two moral dilemmas always the same?
In conclusion, although there are undoubtedly many intricate issues with regard to the subject of war, it is vital to consider the various arguments provided (including those above) such as the view that the ultimate principle should be to preserve life (W.D.Ross) and the conditions set out in the ‘just war’ theory. However, my personal view is that although I can acknowledge the arguments provided by idealist and realist thinkers, I believe that in order to justifiably conduct military action, it is necessary to establish an independent system where universal jurisdiction can be enforced, and which will provide an impartial hearing and sentence those accordingly – such as the United Nations.