Pope Benedict XVI used an address at a Roman Catholic university in the Vatican City on Saturday to reiterate his criticism of scientists whose quest for knowledge leads them to stray morally by conducting research into areas, such as embryonic stem cells, that he said value discovery over life.

“Universities can reveal the fruitfulness of truth,” he said. But “the contemporary world,” he continued, “seems to give pride of place to an artificial intelligence ever more dominated by experimental techniques and thus forgetful that science must always defend man and promote his efforts towards true good,” according to excerpts of the speech posted on the Vatican’s Web site.

Then the pope called up an analogy that, 10 or 15 centuries ago, would have been unheard of for a pontiff to utter. Benedict, a former theology professor, likened the wayward scientists to Icarus, the figure in Greek mythology who fell to his death in the sea when arrogance led him to soar too close to the sun on high-tech wings of his father’s design.

Icarus, “carried away by the joy of discovery,” paid the ultimate price for “his illusion,” Benedict told his listeners at the Pontifical Lateran University. Professors, he said, have “the task not only to investigate truth, ... but also to promote knowledge of every aspect of that truth, defending it from reductive and distorting interpretations.”