natural law

The ambiguity of the term natural law rests upon a metaphorical link between regularities in nature and the authoritative regulation of human activity. In its latter use, ‘natural law’ refers to principles of law and morality, supposedly universal in scope and binding on human conduct. In medieval Christian theology natural law was held to be a God-given system, but from the Reformation onwards, attempts were made to give natural law secular foundations in human nature and reason. In the Leviathan of Thomas Hobbes , for example, ‘laws of nature’ provide rational grounds for the social contract, and so for the establishment of political authority. Since the eighteenth century, legal theory has tended to be hostile to the notion of natural law-the conventional, socially and historically formed character of law being more commonly emphasized. However, the increase in moral authority attaching to human rights since the Second World War owes much to the natural law tradition.

The idea of the natural world as created by God, and so being subject (like human society) to God's authority, led to the metaphorical extension of the notion of natural law to refer to regularities in nature. Here, again, the idea had its religious and its secular adherents, though from the scientific revolution of the seventeenth century, the principal division was between rationalists and empiricists. The former tended to attribute necessity to the laws of nature, some of them (such as Leibniz) supposing these to be rationally demonstrable from a priori principles. The empiricists held that knowledge of the laws of nature could be established only on the basis of observation and experiment. On this view the regularities summarized in laws of nature could not justifiably be held to have any necessity about them. Our expectation that such regularities would continue into the future, however unavoidable in practical life, was (David Hume argued) nevertheless rationally ungrounded, and a mere habit of mind.