I can comment on only a few of the issues the commentators raise within the space allowed me for reply.

Quinn thinks it false to say—as I did—that “severe constraints on liberty may not be imposed in the name of considerations that the constrained are not unreasonable in rejecting.” He offers by way of countercase to that idea the fact (he thinks it a fact) that polygamy may permissibly be prohibited even though those whose liberties are thereby severely constrained are not unreasonable in rejecting “the considerations typically invoked to support such laws.” Exactly which considerations does Quinn have in mind? I suppose that prohibitions on polygamy were originally adopted on the ground of the (putative) immorality of polygamy. But if it is to be acceptable to retain those prohibitions now, there had better be other or further grounds for them.

Compare the laws formerly in force prohibiting interracial marriage. I suppose that those prohibitions were originally adopted on the ground of the (putative) immorality of interracial marriage. I am sure Quinn would agree that that ground for those prohibitions did not then, and would not now, justify them.

Moreover, I am in considerable doubt whether prohibitions on polygamy (or interracial marriage) do count as severe constraints on liberty. As H.L.A. Hart pointed out, prohibiting polygamous marriage leaves a man free to cohabit with any number of women. Constraints on those with whom you may have intimate personal relations would plainly count as severe constraints on liberty; can the same be said of constraints on how many people you may marry?

An immediately relevant question is what form the prohibition takes. Joel Feinberg distinguishes. Society Alpha might merely declare that ‘marriages’ beyond the first are null and void. In Alpha, the parties to the further ‘marriages’ cannot thereby obtain the legal benefits that come of marriage. Is their liberty thereby severely constrained? I doubt it. Society Beta might in addition declare that further ‘marriages’ are a criminal offense. In Beta, the parties to the further ‘marriages’ are in addition penalized for engaging in them. This certainly constrains their liberty; does it severely constrain their liberty? Again, I doubt it.

In sum, I do not think that Quinn’s proposed countercase succeeds. Most of us believe some form of prohibition on polygamy acceptable, but why exactly? I leave that open, for in any case, its adoption does not seem to me to count as a severe constraint on liberty. (Most of us also believe that no form of prohibition on interracial marriage is permissible. But that is not because its adoption severely constrains liberty. Rather it is because of considerations of equality.)

Although I do not think Quinn’s proposed countercase succeeds, I am grateful for it since it is itself interesting, and because it gave me an opportunity to stress that in saying that a prohibition on abortion is a severe constraint on liberty I did not mean merely that women think it is a severe constraint on liberty. We do distinguish, objectively, between what severely constrains liberty and what does not, and it is that distinction I had in mind. I greatly doubt that De Marneffe’s whaler’s liberty is severely constrained by “limiting his freedom to whale”. I suppose that a limitation on the whaling you may do to make a living might constitute a severe constraint on liberty, but if it is to be thought to do so, a case has to be made.

I want to stress also that in saying that women are not unreasonable in rejecting what is standardly given (and is given by the Pope) as ground for prohibiting abortion—namely the doctrine that fertilized human eggs have a right to life—I did not mean merely that women think there is no good reason for accepting it. Here too I had something objective in mind: I meant that there is no good reason for accepting it.

De Marneffe invites consideration of the view that the grounds standardly given for prohibiting abortion may be reasonably rejected as having “no moral weight”. (Does he think I hold this view? I’m not sure.) He then declares that any reasonable person must accept that some of those grounds have some moral weight. But the phrase “moral weight” is his not mine, and I do not know what he means by it. Moreover, since he concedes that those grounds may be reasonably rejected as insufficient to justify prohibiting abortion, it is unclear to me why it matters to him that they do, all the same, have some moral weight.

I think some readers may have thought I meant that nothing at all could justify imposing a severe constraint on liberty, and I probably should have said explicitly that I did not mean this. An emergency would presumably justify it. So might the need to provide public goods (such as national security) in face of a large-scale free rider problem. But putative justifications have to earn their keep. And to the extent to which a putative justification can earn its keep, rejecting it is unreasonable—objectively unreasonable.

Laycock says my attempt to resolve the abortion issue by “allocating the burden of proof to the other side” is “futile”, and I find that puzzling. It is a thoroughly familiar idea that constraints on liberty call for justification, and that the more severe the constraint, the stronger the required justification; can it really be that Laycock rejects that idea? But if one accepts that a would-be liberty-constrainer has the burden of proof, then it is in order to ask whether would-be abortion-prohibitors succeed in carrying it. I have suggested that they do not succeed in carrying it when they declare that fertilized human eggs have a right to life since there is no good reason to believe that doctrine true. The fact that those who make this declaration are, as Laycock says, “honorable people” is neither here nor there.

Regan says my view that there is no good reason to think the doctrine true “raises in turn the deepest issues about how we come to know any moral proposition at all.” And he commends “Bossuet’s central point”, for, he says, “[t]here is no epistemological escape from our moral conundrums.” To suppose that one is not entitled to say there is no good reason to accept the doctrine unless one has solved the deepest problems in moral epistemology seems to me a serious error, though I have no room to discuss it here. In any case, we do well to notice that in commending Bossuet, Regan parts company with the Pope. The Pope does not invite taking action to prohibit abortion on the sheer ground that he is right in thinking it a violation of the right to life: he offers as ground not merely that he is right in thinking this, but that reasonable people should agree—for he says that its being a violation of the right to life is knowable by reason itself. That, however, is exactly what I have denied.