From the point of view of the recognition of the diverse spheres of facts, modes and norms, the traditional distinction between legal rights on the one hand, and ethical, moral, 'natural' or human rights on the other is of paramount importance. The former (which are also called "positive rights") belong wholly or primarily to the factual and modal spheres, whereas the latter belong to the normative and modal spheres. The expressions ethical, moral and natural right themselves may be defined in divergent ways, yet they are always contrasted with the concept of legal rights, and are held to exist prior to, or independently of, the law or other institutionalized social systems; that is, if the existence of ethical, moral or natural rights is acknowledged at all.

While human rights are or would be rights which every human being has as a human being, natural right does not in the same way refer to a biological category of one or more species. It only refers to living beings looked upon from a 'natural', that is, a nonlegal or noncultural perspective. Quite often tho, the sole category of living beings recognized as having natural rights are human beings nevertheless. Thus, an advocate of rights may contend that there is 'at least one natural right, namely the equal right of all men to be free' (not of all natural, living or animal beings). In the context of human rights, moral rights and natural rights may be used interchangebly, but as soon as someone starts talking about rights which are created or conferred by people voluntarily, these special rights are moral rights which are not regarded as natural rights. Human rights themselves have been defined as moral rights of all human beings (or 'people') at all times and in all situations. They have also been defined as general, moral rights which are of a fundamental importance, and which are held 'unconditionally and unalterably'.

The holders of human or moral rights are not always taken to be individuals. According to some theorists they may also be groups of human beings or whole natural communities of nonhuman, or both human and nonhuman beings. In the event that the parties are individuals, human or moral rights may be depicted as the rights of the individual against all other individuals, vis-à-vis the world at large and the state, or only the state, and so forth. It seems odd that someone could ever recognize human rights of individuals vis-à-vis the state only, because the expression human right suggests that the party has the right as a human being, not as a citizen or a member of a state. Logically speaking, to belong to a state, or to live in one, is a contingent matter, 'even for human beings'. Altho the notion of right is very closely related to that of the law and to what the law should be, this conception of human rights is one-sidedly archistic for a supposedly universal right.

Having rejected the view that only citizens or groups of citizens could have human or moral rights, the next point is whether, conceptually speaking, also nonhuman beings can have moral or natural rights. Many human theorists take it that only human beings, and that all human beings, have such rights. (Furthermore, they also equate human being with person, and vice versa.) Some more enlightened theorists of rights have started from the principle that beings which have or can have interests are the kind of beings which can have rights. This includes nonhuman animals, and if this excludes plants, it also excludes human vegetables.

When it is claimed that human rights are possessed by all (human beings), equally by all (human beings), and not on the basis of some subordinate quality like race, sex or social status, this qualification can be applied to any kind of right someone may fancy. For example, animal rights are, then, rights possessed by all (animal beings), 'equally' by all (animal beings), and not on the basis of a subordinate quality like species, sex or the region where the animal lives; or, children's rights are rights possessed by all (children), 'equally' by all (children), and not on the basis of a subordinate quality like descent, sex or age. No theory of rights has ever clarified why exclusively human beings should have 'human rights' because of their being human. No theory can explain why not every category of beings, or of sentient beings, or of beings with interests, should have the specific right of their category. None of the above so-called 'characteristics' of human rights pertains to human beings in particular. This does not only mean that an analogous type of right may pertain to categories which take in (solely) nonhuman beings, but also to any category that comprises only a subclass of human beings (such as citizens or human children), or a subclass of human and another of nonhuman beings (such as persons, logically speaking).

In trying to justify human rights many advocates have taken the preservation of 'mankind', human dignity or some kind of equality as a fundamental 'law' or basic principle. The equality they speak of may be unqualified, may pertain to certain respects in which all persons are equal, to a minimum acceptable equality, or to a political equality. (One natural-rights theorist has 'justified' human equality on the basis of the equal need of continued motion, because human beings are 'self-moving' bodies, which would all 'equally try to continue their motion', and which would all be 'equally fragile'.) Yet, if equality is really a basic principle, it must apply to all beings belonging to the same category as that of 'self-moving bodies'); not exclusively to human beings but to sub- and super-specific categories, and to other species as well. (Political equality is itself already a sort of subspecific principle.) Of course, the founding principles of human rights may be the preservation of humankind and the equality or dignity of all human beings. But why start here, and why stop here?

Some theorists have taken the meaningfulness of life as justificatory quality, but --first of all-- it is not always clear what they mean by life, let alone what they mean by meaningfulness. If life denotes the organismic state of self-moving or living beings, then the 'meaningfulness of life' does not generate human rights, but rights of living beings in general. On the other hand, if life denotes the state of being vital and functioning instead of dead, then this 'meaningfulness' only generates one right: the mandatory 'right' to life of all living beings, or only of mental beings, if both physical and mental experiences are believed to be essential. This intrinsic right corresponds to the general duty not to kill other living or mental beings, nor oneself. It does not imply any extrinsic, or other intrinsic, duty of noninterference, nor does it admit of any personal discretionary right of life, that is, both the right to continue one's own life and the right to finish, risk or sacrifice one's own life. Strictly speaking, it both allows too much (everything except killing) and disallows too much.

Utilitarians who have not rejected the concept of right altogether, have attempted to base their justificatory theory on the maximization of interests. Apart from all its defects, this approach has often been conducive to at least one good thing: the recognition of all living beings that can suffer as the recipients or bearers of rights. Altho this ability to suffer has been used in attempts to justify only human rights, it has correctly been pointed out by those utilitarians that this criterion applies to all sentient beings, and it must therefore be concluded that it is sentient beings which have the rights thus justified.

It has been argued that the objection against traditional consequentialism that it could not accomodate agent-relative values and the autonomy of human beings or people, only applies to utilitarianism and other forms of 'welfarist consequentialism'. It is not necessarily contrary to consequentialism itself to recognize certain kinds of agent-relativity, such as that of the doer or viewer, or to admit such a kind of relativity in the evaluation of the consequences themselves. The evaluation still remains consequence-based then and the goals in which these agent-relative values are now incorporated become the rights of a sort of 'goal-rights system'. Such a system would at the same time provide an alternative for 'constraint-based deontology' which is as inadequate as traditional consequentialism --as the argument goes-- because of its inability to deal with the interdependence of acts of different people. The weight of different rights (and duties) does in such a system itself depend on the consequences and the evaluation of those consequences.

A category which is, biologically speaking, probably not much different from, or equal to, the one involved in questions of utility is the class of beings which have (or can have) interests. Justificatory theories which rest on the having of interests need not attribute rights to all beings which have interests tho. Having interests may be conceived of as a necessary but not a sufficient criterion of having rights. With respect to human rights the result is the same nevertheless: there are either no human rights or, if there are, human rights are merely one kind of rights among many other kinds pertaining to specific classes of beings with interests.

What all the above-mentioned justificatory theories of rights and most other ones have in common, is that if they do justify or explain anything at all, this only or primarily concerns intrinsic general right-duty constellations. If they somehow do concern extrinsic right-duty constellations, then only in terms applicable to all rights, or rights and duties. Such is the case when the concept of interest is introduced (itself not a first-order doctrinal principle) or when a political complexion is put on the principle of equality. Every appeal, however, to doctrinal principles of the same (first) order, can solely justify intrinsic rights and duties. The majority of traditional justificatory theories of rights do not more than that, and not seldom in such an obviously inadequate way that they cannot be taken seriously.