[This post is the first in a series. It draws on an old paper of mine (see 379000 here) and takes a critical view of ideas sometimes used in libertarian advocacy but also central to a traditional Marxian notion of exploitation. I thought I'd give it another outing. Here I merely set the scene, explaining what is to come.]
A justificatory belief system is a complex of interdependent themes and arguments. The whole, typically, has an intricate life: evolving, subject to piecemeal addition or subtraction, to internal shifts rearranging its constituent elements, to critical stricture, defensive reinforcement, creative modification, and so on. It is not always easy in the circumstances to estimate the exact importance of a given element of the whole, to know how much depends on its particular strength. Yet some elements are obviously more central strategically than others, and if it can be shown of any such central element that it is in fact intellectually flimsy, then, other things equal, this weakens the chain of justification in which it is a link.
In this series of posts, I shall focus on what I believe to be a link of this normatively strategic sort, an argument commonly associated with the name of John Locke and used in attempts to legitimate (great) social inequality. The argument derives original moral entitlements to private property from the labour expended by free individuals on virgin natural resources - or, as Locke himself expressed this, the labour 'mixed' with them - and it functions, for many who use it, as a polemical weapon against government interference with private property and the transactions between private proprietors; hence as a weapon against state encroachment upon the 'free' market. Since property titles of such origin, as well as any derived in turn from them by voluntary transfer, are held to be a matter of fundamental right, the state may not impinge on them or on the legitimate dealings of their holders other than in the way of vouchsafing protection.
The argument to be examined I shall call the labour-mixing argument. To suggest that its difficulties had gone unnoticed hitherto would not be right. They have been commented on many times. Given how serious and important they are, though, there is something odd about the way they are generally dealt with. Writers note them briefly - whether because they do not think them overwhelming, or because they think them too obviously so to be worth troubling over - and then pass on to what is of more immediate concern. With one exception to my knowledge, there has been no concentrated effort either of decisive rebuttal or of careful vindication (if the latter is indeed possible). The exception is an article by Jeremy Waldron, the substance of which is also incorporated in his formidably impressive The Right to Private Property.1 What follows takes the same direction as Waldron on this point: it impugns the labour-mixing argument. But there is more, in my own view, to be said about that argument than Waldron says, if we are to understand both its apparent strength, its widespread appeal, and the full extent of its actual weakness.
This is how I shall be proceeding. First, I exhibit the chain of moral reasoning in which I am interested, with one of its key consequences. I then comment briefly on features of it which I either do not challenge in this context or else do not wish to consider, and I say why I do not. That leaves, by elimination, the argumentative link which matters here, and I indicate why I think it really does matter. I go on to examine it: criticizing the labour-mixing argument and related justifications of very unequal private property.
 Jeremy Waldron, 'Two Worries About Mixing One's Labour', Philosophical Quarterly, 33 (1983), pp. 37-44; and The Right to Private Property (Oxford: OUP, 1988), pp. 184-91. I refer, hereafter, to the second of these simply as Waldron.
(Part 2 is here.)