The Pope entrusted this task in particular to the International Theological Commission, when he met with its close to 30 members, who are holding their annual meeting this week in the Vatican.
Natural law has been a key theme of John Paul II's pontificate. He dedicated passages to it in two of his encyclicals, "Veritatis Splendor" and "Fides et Ratio."
Explaining the meaning of the natural moral law during the audience, the Pope said: "It has always been the Church's belief that God gave man, with the light of reason, the capacity to be able to know the fundamental truths on life and his destiny and, specifically, the norms of moral behavior."
"Making our peers aware of this possibility is very important for dialogue with men of good will and for coexistence in all levels on a common ethical foundation," the Holy Father added.
"Christian revelation does not render this search useless," he said. "On the contrary, it pushes us to search, lighting up the path with the light of Christ, in whom everything is consistent."
John Paul II considered it especially appropriate to entrust this challenge to the members of the International Theological Commission, as he counts on their "experience in the different countries of the world" and their "knowledge of the theological problems."
The commission's members are appointed by the Pope for a period of five years. To guarantee its international character, in general no two theologians come from the same country. An effort is also made to have diverse theological schools represented.