That issue, of course, is abortion. And the Catholic News Agency today filed this report of a remarkable debate on the issue that just took place in Colorado:

A Catholic-sponsored debate about the ethics of abortion packed hundreds into an auditorium on the University of Colorado campus in Boulder, CO this past Friday night. The debate featured two prominent philosophy professors—Drs. Peter Kreeft and David Boonin—who defended their views on the ethics of abortion.

Listeners filled all 288 seats of the auditorium, while others sat in the aisles. Still more sat in the overflow seating in the basement hallway, and even crowded the stairs leading up from the basement, a total audience easily surpassing 400 in number.

The debate, sponsored by the Thomas Aquinas Institute for Catholic Thought, addressed the question “Is abortion morally justifiable?” Dr. Peter Kreeft, of Boston College, answered that it could never be while Dr. David Boonin of the University of Colorado argued that abortion was sometimes a moral choice. Both professors offered many reasons and counterarguments defending their position.

The professors are both prominent in their field and in the public eye. Kreeft has authored more than 45 books dedicated to defending Christian beliefs and understanding suffering, morality, philosophy, life, and God. Dr. Boonin’s 2003 book “A Defense of Abortion” won an honorable mention from the American Philosophical Association. Boonin is also the chair of the University of Colorado’s philosophy department.

Dr. Kreeft opened the discussion with an “intuitional” appeal, saying “more people in fact are convinced by seeing, by experiencing, than by arguing.” He noted that people usually change their minds through personal relationships rather than through strictly rational analysis. He advised the audience to listen to the “inner shock” of conscience.

Shifting to an explicit rational argument, Kreeft took the position that a human fetus is a person possessing many rights, including the right to life. He also argued that people cannot rationally deny the right to life of the unborn without denying the right to life of newborns.

He recounted how he once discussed abortion with “some very intelligent feminists,” claiming that they had no argument justifying abortion that would not also justify infanticide.

“After the argument they came up to me and said ‘Congratulations, professor, you changed our minds. We didn’t think you could do that.'”

“‘Oh, good,’ I said, ‘you’re pro-life now?'”

“‘No, we’re pro-infanticide’,” Kreeft finished, prompting surprised laughter from the audience. “So logical consistency can be a two-edged sword,” he noted.

Even someone who was unsure if an unborn child is a person, Kreeft argued, would in the absence of certainty have to refrain from having an abortion. To kill someone without knowing if they are human is still homicide. To act in a rash manner that could kill someone, such as poisonously fumigating a room without being sure it was empty of people, would amount to criminal negligence. Barring certain knowledge that an unborn human is not a person, abortion similarly would be blameworthy even if the human fetus were not a person with the right to life.

Dr. Boonin began his remarks with a general comment criticizing the belief that the only arguments against abortion are religious arguments. “In fact, there are a number of distinct arguments, potentially quite powerful arguments,” against abortion that do not refer to God and rely on reasonable premises that people on both sides of the abortion debate would accept. He said Kreeft’s opening remarks were examples of such reasoning.

Boonin then presented criticisms of some general pro-life arguments and raised some philosophical concerns about Kreeft’s arguments. Boonin said that it was “implausible” to many people that human membership automatically entailed having the right to life. One such case is that of an individual whose capacity for consciousness is lost when most of his brain is physically destroyed.

Boonin suggested that Kreeft’s argument that any moral uncertainty about moral status of the unborn child meant all abortions were at minimum morally blameworthy could have radical implications if applied consistently. This “appeal to uncertainty,” as he called it, could require pacifism, vegetarianism, opposition to capital punishment, and the advocacy of a moral imperative to give all of one’s excess income to those in need.

There’s much more, well worth reading, at the link.