Benedict XVI says that natural law must be the foundation of democracy, so that those in power are not giving the chance to determine what is good or evil.
The Pope said this today when receiving in audience the members of the International Theological Commission, who had just completed their annual plenary meeting, held in the Vatican this week under the presidency of Cardinal William Levada.
The Holy Father discussed with the theological experts what he considers the antidote to "ethical relativism."
Natural law, the Pontiff explained, is "the norm written by the Creator in man's heart," which permits him to distinguish good from evil.
But, he contended, partly because of "cultural and ideological factors, today's civil and secular society is in a situation of confusion. The original evidence for the foundations of human beings and of their ethical behavior has been lost, and the doctrine of natural moral law clashes with other concepts that run directly contrary to it.
"All this has enormous consequences on civil and social order. A positivist conception of law seems to dominate the thought of many scholars."
Benedict XVI explained that according to these scholars, "humanity, or society, or in effect, the majority of citizens, become the ultimate source for civil legislation."
He continued: "The problem that arises is not, then, the search for good but the search for power, or rather the balance of power.
"At the root of this tendency is ethical relativism, which some people even see as one of the principle conditions for democracy because, they feel, relativism guarantees tolerance and mutual respect.
"But if this were true, the majority at any given moment would become the ultimate source for law, and history shows with great clarity that majorities can make mistakes.
"True rationality is not guaranteed by the consensus of the many, but only by the openness of human reason to the reason of the Creator and by listening together to this Source of our rationality."
Benedict XVI affirmed that natural law is actually a guarantee of freedom.
He explained: "When fundamental essentials are at stake: human dignity, human life, the institution of the family and the equity of the social order -- in other words the fundamental rights of man -- no law made by men and women can subvert the norm written by the Creator in man's heart without society itself being dramatically struck ... at its very core.
"Thus natural law is a true guarantee for everyone to live freely and with respect for their dignity, protected from all ideological manipulation and from all arbitrary abuses of the powerful.
"No one can disregard this appeal. If by reason of a tragic clouding of the collective conscience, skepticism and ethical relativism managed to annul the fundamental principles of natural moral law, the very democratic order itself would be profoundly undermined at its foundations."
The Pope said that men and women of all faiths should combat this possibility.
He said: "Against such clouding -- which is a crisis for human, even more than for Christian, civilization -- the consciences of all men and women of good will must be mobilized, both laypeople and followers of religions other than Christianity, so that together they may make an effective commitment to creating ... the conditions necessary for a full awareness of the inalienable value of natural moral law.
"The advance of individuals and of society along the path of true progress depends upon respect for natural moral law, in conformity with right reason, which is participation in the eternal reason of God."