Charles J. has distinguished a number of different modes of libertarian thickness (see here and here), but I think I’ve got a new one. At first I thought it was just a special case of application thickness, but the latter seems to be primarily an epistemic matter, applying to cases where the non-aggression principle in fact entails X independently of value Y, but people have a hard time seeing that it does unless they view the matter through the lens of Y. At least this seems a natural reading of Charles’s two chief examples of application thickness:
Think of the feminist criticism of the traditional division between the “private” and the “political” sphere and those who draw it in such a way that systematic violence and coercion within “families” are justified, or excused, or ignored, as something “private” and therefore less than a serious form of violent oppression. Or the way in which garden-variety collectivism prevents many non-libertarians from even recognizing taxation or legislation by a democratic government as a form of coercion in the first place.
The kind of thickness I’m talking about, by contrast, concerns cases in which the non-aggression principle doesn’t entail a definite result without the help of value Y. Consider a case in which there are a variety of different possible ways of applying the non-aggression principle, all equally compatible with the principle itself. In such cases it might be argued that we should allow some additional value or commitment to decide among these options. Now this additional value might be one that is connected to non-aggression via one of the other modes of thickness, but it might equally be one that is simply valuable for independent reasons. In the latter case – and arguably in the former as well – we have a mode of libertarian thickness that doesn’t seem reducible to any of the others; let’s call it “specification thickness.”
Nothing new here, really – both Charles and I have written about the problem of “reducing” or “specifying” the natural law (see here and here), though by means of conventions; but I’ve also written (here) about how one part of virtue helps to specify the content of another. Moreover, specification thickness is essentially Kevin Carson’s argument (here) for his mutualist position on land ownership; Kevin thinks that the Lockean, Georgist, and mutualist positions all represent equally possible applications of libertarian principle, and so he argues for mutualism on the grounds that it is best supported by various additional values. Plus I gave an analogous argument (different content, same structure) at at least one Mises conference.
So I’ve had all the pieces for identifying this additional form of thickness for a while, but for some reason I didn’t start to put them together until I was preparing for my thickness talk at FEE (and even there I was still calling it one form of application thickness).
Im now inclined to treat specification thickness as a form of application thickness, and to treat the purely epistemic version (call it recognition thickness) as a different form of application thickness.