Well it depends what you mean by "pure" restitution. A duty of care standard would, I suppose, be consistent with having rights-violators compensate victims for damages, but incur no further punishment. I don't see any problem with that from a practical standpoint. Generally, however, the duty of care standard is associated with the view that the law exists at least partly to punish wrongdoers, rather than strictly to ensure that victims do not bear the costs imposed on them by the actions of others. My standard example of "duty of care"-style thinking comes from Section 8 of Locke's On Civil Government:
And thus, in the state of nature, one man comes by a power over another; but yet no absolute or arbitrary power, to use a criminal, when he has got him in his hands, according to the passionate heats, or boundless extravagancy of his own will; but only to retribute to him, so far as calm reason and conscience dictate, what is proportionate to his transgression, which is so much as may serve for reparation and restraint: for these two are the only reasons, why one man may lawfully do harm to another, which is that we call punishment. In transgressing the law of nature, the offender declares himself to live by another rule than that of reason and common equity, which is that measure God has set to the actions of men, for their mutual security; and so he becomes dangerous to mankind, the tye, which is to secure them from injury and violence, being slighted and broken by him. Which being a trespass against the whole species, and the peace and safety of it, provided for by the law of nature, every man upon this score, by the right he hath to preserve mankind in general, may restrain, or where it is necessary, destroy things noxious to them, and so may bring such evil on any one, who hath transgressed that law, as may make him repent the doing of it, and thereby deter him, and by his example others, from doing the like mischief. And in the case, and upon this ground, EVERY MAN HATH A RIGHT TO PUNISH THE OFFENDER, AND BE EXECUTIONER OF THE LAW OF NATURE.
Force in defence will entail both direct self-defence and force used to make sure the victim is made whole, in all cases proportionate to damage done to the victim. And no, I do not see how the aggressor could possibly defend against it (unless it were disproportionate). They'd just be trying to avoid suffering the consequences of their aggression, so it'd be "defence" but in the loosest sense of the word possible.
-Jon
Freedom of markets is positively correlated with the degree of evolution in any society...
But you agree that there is no objectively proportionate degree of restitution for an act of agression, nor any objectively legitimate agent to enforce it, no?
Yeah, I'm a bit iffy on how restitution should be determined given the subjective nature of harm. Perhaps common law standards will determine this. I haven't devoted much attention to the matter of restitution/punishment as of yet. As for the latter, yes, if the victim is excluded at least from the analysis.
So I guess my point is, if the alleged initial aggressor didn't voluntarily consent to the restitution, you'd need to appeal to some moral authority that you might not have in enforcing justice under the NAP. If you want my opinion, it's just too simple of a moral framework; conflicts cannot be solved by simple reference to the question, "Is there, or was there, aggression?" So much more needs to be said. [Sorry, that was premature]
One could always go the other way, of course, and question whether a lack of moral authority is truly that much of a tragedy for the principle, or whether restitution is indeed a viable principle at all, IOW extend the anarchist re-examination of the notion of justice to restitution as well.
Well I completely agree that anarchists need to extend their examination. But under my framework for thinking about rights, you'd only need to ask yourself whether the desire to restore justice would be morally significant enough a reason to use the means you were contemplating. If you were handcuffed by the NAP, I think you'd be hard pressed to deal with that sort of situation non-pacifistically. That's why a lot of anarchists have argued against the use of force in enforcing justice, instead claiming that the way justice should be enforced is by refusing violators access to your property, so that they would "have to" "voluntarily" accept justice (ha.).