The strengths that can be ascribed to natural law are a product of its absolutist deontological view of morality. This is to say that it enables people to establish common rules in order to structure communities. This can be an attractive option in a society such as our, enduring a relativist era that is suffering from a break down in traditional social structures and moral uncertainty.
Aquinas’s view of reason as a tool for moral understanding and his idea of a common nature and morality for all people gives natural law a universality that goes beyond any one religion or culture. This can be seen as a very positive aspect considering the intercultural strife and disharmony that exists between cultures and societies which all uphold similar basic principles such as conserving life.
Natural moral law gives a concrete reason to be moral and provides a firm basis for individuals to refuse to cross moral boundaries. It also provides justification and support for those ideas popular in today’s world such as human rights, whilst condemning actions such as torture, irrespective of consequences. Natural law also provides a way of living, giving guidance on day-today questions of how to live life and then links them to the fundamental principles of life. It provides a complete system of moral living in step with what it is to be human. This may be a most attractive proposition for some, which suggests that it is most certainly strength of natural moral law.
Some have challenged Aquinas. They have questioned the existence of a common natural law that is apparent and self-evident. One who made such a challenge was Neilson In his article ‘An examination of the Thomistic theory of natural moral law’. Neilson argued that human nature isn’t as self-evident as Aquinas claims and cites anthropological studies such as Scandinavians who killed their elderly relatives in order to let them into Valhalla, claiming that these differing moral standards cast serious doubt over the idea of a common natural law within all human societies. Nielson goes on to say that Natural law obscures these basic moral differences that exist between human societies.
There is also the possibility that a natural law does exist, but it is more complex than Aquinas believed. For example, Aquinas ruled homosexual activity as un-natural as it does not lead to pro-creation, but perhaps for those involved they find love and purpose in life through expression of their sexuality. This example serves to highlight the suggestion that perhaps what is ‘natural’ differs depending upon circumstances.
In their book The Puzzle of Ethics Peter Vardy and Paul Grosch challenge the way in which Aquinas works from general principles to lesser purposes. Aquinas maintains that as human beings must preserve the species, every discharge of semen should be associated with life generation. To use the genitals in other ways is immoral. However, one could perhaps justify sexual acts on the premise that they further the couple’s relationship. If this is the case then it is not necessary for every discharge of semen to be associated with life generation. It could be then that Aquinas was wrong in his deductions, as they may have been based upon an incorrect view of human life. This was perhaps as a result of thirteenth century naivety on Aquinas’ part.
Vardy and Grosch also consider Aquinas’ view of human nature unholistic. Perhaps the genitals are for pleasure rather than reproduction, or some other purpose, maybe even a multitude of purposes. It could also be that sexual activity does not only found in the genitalia. Psychologists have drawn much more complex pictures of human nature than that presented in Aquinas’ simplistic account. In contrast to Aquinas’ apparent belief in a fragmented collection of parts, today the human body is seen as one psychophysical whole.
Aquinas’ natural moral law is a Christian ethic and yet Jesus quite clearly opposes legalistic morality in the New Testament. Jesus debated frequently with moral legalists of his time, the Pharisees. Similarity can be found between Pharisaic law and natural moral law. As a result, some, such as Joseph Fletcher argue that Jesus himself has rejected natural moral law.
Some Christian ethicists argue in favour of a morality that is based more on the person involved rather than the acts committed. One such writer is Kevin T. Kelly, who in his book ‘New directions in Moral Theology’ identified two traditions found in Christian morality. One of these is centred upon acts, and the other is centred on the dignity of a human person. Kelly sees both of these strands of morality at work in recent Christian thinking. The Constitution of the Roman Catholic Church, Gaudium et Spes, maintains that ‘the moral aspect of any procedure is influenced by intentions and motives but also objective standards, based on the nature of the human person and his acts’. Kelly argues for a morality based on the human person as author and director of any actions, and moves away from the idea that actions have moral value in themselves. A more extreme form of personalism as demonstrated by Kelly, can be found in situation ethics, which abandons an uniform legalists approach to morality in favour of consideration of the situation and the results of actions that in turn determine the goodness or badness of an action and not the action in itself.
Given the criticisms raised against natural law, it is worth pointing out that natural law may not be as rigid as it my first appear. Aquinas observed that although primary precepts were unchangeable, the secondary precepts might change in some particular aspects, or in a case in which special reasons make it impossible to observe them.
In trying to decide then, if natural moral law can be held as a definitive ethical theory one has to realise that although the theory isn’t as rigid as it first appears it is still faced with problems, which may well, be insurmountable. The conclusions of the Roman Catholic Church regarding the prohibition of activities such as artificial contraception and homosexual acts, as already shown, can be subject to convincing challenge. It is also important to note that in the absence of clear guidelines it is impossible to know definitively what is and what is not natural and so therefore rendering the issue wholly subjective. Once an issue becomes subjective, and it is difficult to produce an instance when subjectivity would be absent, natural moral law has to fail as a definitive ethical theory.