One of his blog posts gives a good summary:
On this anniversary of the adoption of the Universal Declaration of Human Rights, it is worth reflecting on the nature of human rights and what functions they perform in moral, political and legal discourse and practice.
For moral theorists, the dominant approach to the normative foundations of international human rights conceives of human rights as moral entitlements that all human beings possess by virtue of our common humanity. What constitutes a human right, according to this approach, isn’t determined by a positive legal instrument or institution. Human rights are prior to and independent of positive international human rights law. Just because a legal order declares something to be a human right doesn’t make it so. Conversely, the fact that a human right doesn’t receive international legal protection doesn’t mean that it isn’t a human right. The existence or non-existence of a human right rests on abstract features of what it means to be human and the obligations to which these features give rise. The mission of the field is to secure international legal protection of universal features of what it means to be a human being.
On moral accounts such as these, human rights protect essential characteristics or features that all of us share despite the innumerable historical, geographical, cultural, communal, and other contingencies that shape our lives and our relations with others in unique ways. They give rise to specifiable duties that we all owe each other in ethical recognition of what it means to be human. Rights and obligations can also arise from the bonds of history, community, religion, culture, or nation. But if such rights relate simply to contingent features of human existence, they don’t constitute human rights and don’t merit a place on the international legal register. And if we owe each other duties for reasons other than our common humanity – say, because of friendship, kinship, or citizenship – then these duties don’t correspond to human rights and shouldn’t be identified as such by international legal instruments.
In recent years, political theorists have generated a distinctive account of the nature and role of human rights. Unlike most moral approaches, which focus on universal features of our common humanity, political conceptions define the nature of human rights in terms of their discursive function in global politics. Human rights, according to political conceptions, don’t necessarily correlate to the requirements of moral theory. Global human rights practice, for several political theorists, is a social practice whose participants invoke or rely on human rights as reasons for certain kinds of actions in certain circumstances. They represent reasons that social, political, and legal actors rely on in international arenas to advocate interfering in the internal affairs of a state and to provide assistance to states to promote their protection. What this practice reveals is that human rights protect urgent individual interests against certain predictable dangers associated with the exercise of sovereign power. States have a primary obligation to protect urgent interests of individuals over whom they exercise sovereign power, but external actors, such as other states and international institutions, have secondary obligations to secure protection when a state fails to live up to its responsibility.
Legal theorists of human rights, in contrast, typically start from the premise that international law, not moral theory or political practice, determines their existence. An international human right to food, for example, exists because the International Covenant on Economic, Social and Cultural Rights enshrines such a right. Its international legal status as a human right derives from the fact that international law, according to the principle pacta sunt servanda, provides that a treaty in force between two or more sovereign states is binding upon the parties to it and must be performed by them in good faith. Similarly, the right to development is a human right in international law because the UN General Assembly has declared its legal existence. The international legal validity of a norm – what makes it part of international law – rests on a relatively straightforward exercise in legal positivism; a norm possesses international legal validity if its enactment, promulgation, or specification is in accordance with more general rules that international law lays down for the creation of specific legal rights and obligations.
Determining the legal validity of an international human right is a relatively simple legal task. But legal validity doesn’t determine the normative purpose of a human right, and legal conceptions of human rights that seek to explain their purpose in terms that go beyond positivistic accounts of their legal production threaten to reintroduce moral and political considerations into the picture, which undermines the possibility that human rights can be understood in distinctly legal terms.
For example, human rights in international law are legal outcomes of deep political contestation over the international legal validity of the exercise of certain forms of power. Such contestation doesn’t cease upon the enactment of an international instrument that enshrines a human right in international law. Contestation continues over its nature and scope in particular contexts as diverse as individual or collective disputes requiring international legal resolution, opinions offered by international legal actors on state compliance with treaty obligations, juridical determinations of the boundaries between domestic and international legal spheres, and negotiations among state actors that yield binding or non-binding articulations of international legal obligations. Once transformed from political claim into legal right, and as subsequently as a result of interpretive acts that elaborate their nature and purpose, human rights in turn empower new political projects based on the rules they establish to govern the distribution and exercise of power. How to separate the legal dimensions of human rights from their political origins and outcomes is a challenge to those who seek to ascribe legitimacy to human rights in distinctively legal terms.
In my work, I seek to meet this challenge by defining the nature and purpose of human rights in terms of their capacity to promote a just international legal order. On this account, the mission of international human rights law is to mitigate the adverse effects of how international law deploys sovereignty as a legal entitlement to structure global political and economic realities into an international legal order. It contrasts this legal conception of international human rights with dominant moral conceptions that treat human rights as protecting universal features of what it means to be a human being. This account also takes issue with dominant political conceptions of international human rights, which focus on the function or role that human rights play in global political discourse. It demonstrates that human rights traditionally thought to lie at the margins of international human rights law – minority rights, indigenous rights, the right of self-determination, social rights, labour rights, and the right to development – are central to the normative architecture of the field.
tened by climate change.“
Hans Thoolen on Human Rights Defenders and their awards 