It would be foolish of me to attempt to say anything substantive about the ethics of abortion in a blog post. But I do want to comment on Obama’s recent foray into the question, as well as on one interpretation of those comments. Addressing the graduating class of Notre Dame University, a traditionally Catholic university, and in the face of demonstrators denouncing him for his ‘pro-choice’ views, Obama called for each side to be respectful of the other. We can, he said, avoid demonizing one another, and work together on common causes. In particular, he said, we can work to reduce the number of abortions, by reducing the number of unintended pregnancies, and work also to make the lives of women who go ahead with pregnancies in difficult situations more bearable.

Now some of this is surely sensible. But is abortion really an issue on which (as Jean Edelstein, commenting in the Guardian puts it) we can “agree to disagree”? The phrase “agree to disagree” is usually used to mean to put our differences to one side and tolerate one another’s point of view. In certain areas we can surely agree to disagree about abortion – that was Obama’s point – but not on the central issue: whether abortion is to be permitted or not. That’s a yes/no question, not one which tolerates ambiguity.

Philosophers sometimes distinguish between morality and ethics in the following way. Morality is the set of rules that are binding on everyone, whereas ethics consists in one’s own personal standards. The morality/ethics distinction usually coincides with a degree of seriousness, but it may not: someone may think that lying is immoral, but not all that seriously wrong. When something is immoral and seriously wrong, we usually give it the force of law. To say something is seriously immoral just is to say that it ought to be prohibited.

The morality/ethics distinction captures a great deal of what is at stake when views about permissibility of conduct are grounded in overarching metaphysical systems (such as religion). Many of the things that believers hold to be wrong they will (grudgingly or not) accept constitute part of their ethics. They will accept, for instance, that though sex outside marriage is unethical, they cannot demand that this standard be imposed on everyone. But I doubt that the distinction can help here. The question over which the sides disagree is whether abortion is immoral or merely unethical. If you think abortion is murder (or at any rate very seriously wrong), then it doesn’t make sense to relegate it to the domain of the ethical. Similarly, if you think that prohibiting abortion is a serious infringement on the rights of women, you can’t take a relaxed attitude toward it.

The narrow scope for mutual respect and toleration actually comes out quite nicely in Obama’s own speech. He calls on Americans to ‘reduce unintended pregnancies’. Put like that – at that level of abstraction – that is indeed  a goal towards which both sides can work. That’s why Obama used this kind of language. But the language hides the real disagreement, because of course each side tends to have quite different views on how this end is to be achieved: the ‘pro-life’ side favoring abstinence and opposing contraception (this was a Catholic university, recall) and the ‘pro-choice’ side favoring contraception. We can use inclusive language to describe both options, but it’s a bit like describing the goals of the side as ‘promoting the moral good’ – it’s a cheat.

None of this is meant to show that Obama’s call that we engage in moral debate with mutual respect and without demonizing one another is impossible. It might even be a good thing (from where I stand, and without giving my own views away, I see plenty of people on the other side who do not deserve respect; I am sure that those in the other camp would say the same thing, and sometimes they would be right). And this might well be all that Obama meant. But we cannot avoid the substantive debate; we cannot, consistent with our moral commitments, agree to disagree.