This year we celebrate the 60th anniversary of the UN Universal Declaration on Human Rights and 40th anniversary of the promulgation of Humanae Vitae, Pope Paul VI’s encyclical “On the Transmission of Human Life”. Are they connected with each other and, if so, how?

This is the question posed by one correspondent, who even points in the direction an answer might take. He is not looking for an article on the principles of Catholic Social Teaching, but something on “the why (the value) behind them, [namely] that man has a moral dimension to his life, which he must live by in order to be whole”. Further, he adds, “God must be seen as the lynch-pin holding the whole thing together.” And of course he is right.

World War II demonstrated to humanity the horror and devastation caused by governments which treated human beings as less than human and so were liquidated for ideological reasons. Statesmen from East and West, from the most diverse cultural and religious backgrounds, recognized that the principal bulwark against a repeat of the disregard for human life that characterized the War period should be respect for those human rights which every human being enjoys simply because he or she is human.

For this reason they produced the UN Universal Declaration on Human Rights as a kind of measure for all laws and State activity. It was an affirmation of objective moral criteria with which to judge all laws and governmental action.

However, a philosophical and legal development took place soon after, which led to the denial of the existence of any objectivity in moral norms. Based on the scientific mentality, i.e. the belief that objectivity was limited to what could be quantified or measured, morality, which cannot be quantified, was seen to be essentially subjective. Against the background of the theory of evolution, human nature was considered not something fixed but subject to change. This denial of any common human nature was articulated most persuasively by JP Sartre and the French existentialists. Morality was thus considered to be essentially irrational, a kind of personal preference or feeling (resulting perhaps) from the accidents of genetics and environment.

The affirmation of the pluralism of cultural traditions soon led to the claim that there was also a plurality in morals (Isaiah Berlin) – and so the denial of a moral order that is universally binding on all. To claim otherwise was to “impose” on others one’s (irrational) personal preference. In the wake of these developments, the only recognized moral criterion was the principle of utility. What is useful is moral.

This usefulness is generally interpreted by legislators in terms of economic considerations, seen most recently in the readiness of the Government and the EU to sanction destructive, embryonic stem-cell research. The correspondent who posed this question comments: “As recently as the fall of Communism, living by moral principles was seen as indispensable to mankind’s continued existence; now it seems that man is merely an actor in a morass of economic considerations.”

Humanae Vitae was ostensibly about birth control. In fact, it was also, if not primarily, about the nature of morality, namely whether or not there was an objective moral order rooted in our common humanity. Those theologians (and bishops) who rejected the Church’s teaching went on to develop a new moral theology that was but a variant on utilitarianism, a subtle variant, but nonetheless utilitarian. They denied the existence of any moral absolutes, i.e. any human actions that were intrinsically wrong irrespective of the motivation or circumstances.

Behind this was the denial that there is a common human nature. Instead, human nature was considered to be dynamic and historical – and so morality was understood to be subject to change. What was immoral yesterday, could be moral today. In this new context, conscience became paramount. Not the conscience that was capable of perceiving objective truth – but a purely subjective conscience, what “I” think is right is right for me – and so subjective sincerity became the main criterion not objective truth. In this way, the moral relativism of the post-war period together with its utilitarianism seeped into Church life.

Behind the denial of an objective moral order is the denial of a common human nature – which in turn arises from the denial of God, the creator. “Jean Paul Sartre has said that all of French Existentialism is to be found in Ivan Karamazov's contention that if there is no God, everything is permitted” (Katharena Eiermann). Because we are created in the image and likeness of God, we reflect something of the unchanging nature of God in our own transitory nature.

That something is morality, what the ancients called the natural law, which in turn reflects the eternal law. It was written down for us in the Ten Commandments, summed up in the dual commandment of love, and clarified in all its implications by the Church in its mature moral teaching. Human rights are a modern expression of the same natural law. But unless they are grounded in our God-given human nature, they too dissolve into the morass of economic considerations where might alone is right.

D. Vincent Twomey, SVD, is the author of Benedict XVI: The Conscience of Our Age, (Ignatius Press 2007) and The End of Irish Catholicism? (Veritas 2003).