First, there are debates focused on empirical problems, which are simply arguments over the way things are in our society. There are plenty of useful debates like this: Will it make us safer if we invade Barataria? Will gun control reduce violent deaths? Will the proposed artichoke subsidy be good for the poor? Is there any such thing as a witch?
On the other end of the spectrum, though, are debates that don't have much at all to do with empirical evidence but instead with moral questions. Is slavery evil? Is it okay to be naked in public? Should incest be prohibited? Should we burn a witch if we ever find one? Empirical analysis, if it exists at all here, is often an attempt to duck the fundamental moral question at the heart of the issue.
|Everyone agrees on what's going on here. The only question is its moral significance.|
The abortion debate belongs to this second class. Almost everyone is clear on the facts. (Of course, there are a few empirical disputes—take, for instance, the debunked hypothesis that abortions cause breast cancer.) But the major grounds of dispute are moral, and mostly boil down to two questions: how bad is it to destroy a fetus? and what are the rights of a pregnant woman? These questions cannot be answered with empirical data. They are questions of transcendent morality, and thus fundamentally unsuited to public debate. A citizen has his convictions, and he can certainly attempt to tug on the heartstrings of any of his fellow citizens if he chooses to. But a Catholic who believes that abortion is murder and a liberal who thinks it's fine will be at an impasse until one of the two gives up her a priori moral convictions.
This isn't, though, a polar divide. The gay-marriage debate, for instance, falls in the middle of the spectrum. On the one hand, it is an area in which there is tremendous empirical confusion, filled with answerable questions like: what are typical outcomes for children of same-sex couples? will allowing same-sex marriage damage traditional marriages? is gay marriage likely to lead to legal polygamy? I've personally seen reasonable people change their mind on gay marriage after being exposed to empirical evidence. On the other hand, though, there's a strong moral undercurrent to the debate that doesn't have much to do with the facts. The result is that if I support gay marriage, I have no chance of persuading a fundamentalist Evangelical who believes that it is an evil in itself. Last year, I found myself in a conversation about gay marriage with a nonreligious man whom I respect very much. "I don't think it's right," he said. "It's against the values I was raised by." And there were no two ways about it.
And now for my prescription: when it comes to moral debates, we're better off not having them unless we're simply interested in what our fellow citizens think, or unless we think that our opponent is working from inconsistent moral axioms. By and large, we should solve moral debates by voting, not by arguing.
With empirical debates, full steam ahead.
And when it comes to mixed debates, we must separate out the empirical disputes and focus on them exclusively. For when it comes to debating morality in public, we don't have a logical leg to stand on.