In Anarchy, State, and Utopia, Robert Nozick seeks to demonstrate that principles of justice in acquisition and transfer can be applied to justify the minimal state, and no state greater than the minimal state. That approach fails to acknowledge the critical role that forced exchanges play in overcoming a range of public goods and coordination problems. These ends are accomplished by taking property for which the owner is compensated in cash or in kind in an amount that leaves him better off (by his own lights) than before the transaction. Forced exchanges use coercion to form the state, but the just compensation requirement guards against redistribution state imposed redistribution for collateral purposes. Once these forced exchanges are allowed to form a state, then they may be used thereafter to justify the powers of taxation and eminent domain used to support infrastructure (roads, sewers, public utilities) that neither the minimal state nor private markets can supply.

In the first part of this article, I argue that even those entities that in their own right and for their own sake give us reason not to destroy them and to help them are sometimes substitutable for the good of other entities. In so arguing, I consider the idea of being valuable as an end in virtue of intrinsic and extrinsic properties. I also conclude that entities that have claims to things and against others are especially nonsubstitutable. In the second part, I argue that cloning poses no threat to the nonsubstitutability of these entities (and in this sense, to the dignity of persons). I also consider the relation between cloning and (what I called) holistic identity, and between the latter and genetic identity. In the concluding part of the article, I try to distinguish cases where identity over time and so-called person-affecting acts have and do not have greater moral significance than nonidentity over time and nonperson-affecting acts. I try to apply my results to cases involving embryos, future generations, and to the so-called Non-Identity Problem.

Technologies are being developed for significantly altering the traits of existing persons (or fetuses or embryos) and of future persons via germ line modification. The availability of such technologies may affect our philosophical, legal, and everyday understandings of several important concepts, including that of personal identity. I consider whether the idea of personal identity requires reconstruction, revision or abandonment in the face of such possibilities of technological intervention into the nature and form of an individual's attributes. This requires an account of the work done by the concept of personal identity, and an explanation of what “conceptual impacts of technology” and “conceptual reconstruction” might mean.

Our existing notions of personal identity and related ideas such as personhood and autonomy may seem unable to comfortably accommodate the possibilities of technologically directed trait formation and development. This is a matter of moral and legal importance because the idea of personal identity embeds major values and reflects value-laden beliefs and attitudes. The assumed endurance of identity underlies interpersonal relationships, the assignment of rewards and punishments, and the very idea of what constitutes an autonomous person. Perhaps radical restructuring or even abandonment of concepts are sometimes called for when the world changes drastically, but I suggest that conceptual modification is not “compelled” for personal identity except under extreme circumstances—the remote possibility of rapid human “shape shifting” where physical and mentational attributes can be transformed quickly and continuously.

Efforts to enhance human traits, including merit attributes and other resource-attractive characteristics (e.g., intellectual and athletic aptitudes, physical size and appearance), may generate legal problems wherever the persistence of identity is presupposed. Some advance speculation is thus warranted on how trait change generally will be managed within our legal and socioeconomic systems, and more particularly on rights of access to trait-altering technologies. I mention the possible distributive effects of enhancing highly-resource attractive traits, including the strengthening individual powers to acquire still more increments in such traits in a self-reinforcing cycle. A brief review of some constitutional issues bearing on trait change completes the discussion.

I conclude that existing and projected technologies do not impel the abandonment or remodeling of the idea of personal identity. We may, however, have to reconsider some uses of this concept in different settings, to rethink our understandings of ideas of merit and desert, and to deal with the distribution of resources that may enlarge and entrench the “distances” between social and economic groups.

If we have a natural right to liberty, it is hard to see how a state could be legitimate without first obtaining the (genuine) consent of the governed. I consider the threat natural rights pose to state legitimacy. I distinguish minimal from full legitimacy and explore different understandings of the nature of our natural rights. Even though I conclude that natural rights do threaten the full legitimacy of states, I suggest that understanding our natural right to liberty to be grounded in our interests in a certain way might not commit us to requiring consent for minimal legitimacy. Thus, even if natural rights effectively block the full legitimacy of states - on the assumption that rarely, if ever, the requisite consent will be forthcoming - they may allow minimal state legitimacy.

This paper argues that libertarian political philosophers, including Robert Nozick, have erred in neglecting the problem of political obligation and that they ought to embrace an actual consent theory of political obligation and state legitimacy. It argues as well that if they followed this recommendation, their position on the subject would be correct. I identify the tension in libertarian (and especially Nozick's) thought between its minimalist and its consensualist strains and argue that, on libertarianism's own terms, the consensualist strain ought to prevail. I then describe the form of the consent theory that I recommend to libertarians. The paper concludes with an extended defense of this form of consent theory against contemporary liberal-egalitarian criticisms of it (both explicit and implicit), including those of Dworkin, Rawls, and their followers.

I offer a defense of the moral side-constraints to which Robert Nozick appeals in Anarchy, State and Utopia but for which he fails to provide a sustained justification. I identify a line of anti-consequentialist argumentation which is present in Nozick and which, in the terminology of Samuel Scheffler, moves first to affirm a personal prerogative which allows the individual not to sacrifice herself for the sake of the best overall outcome and second moves on to affirm restrictions (i.e., moral side-constraints) which prohibit the individual from suppressing others' exercise of their personal prerogatives even if that suppression would serve the overall good. I argue that one ought to follow this line of anti-consequentialist argumentation all the way to the affirmation of restrictions by showing that the rationale for the adoption of the personal prerogative is not satisfied unless the accompanying restrictions are adopted as well.