of his attack on what he calls 'the ruling theory' of legal positivism.
Positivism is for him a combination of connected claims: that
law is a system of explicitly adopted or enacted rules; that law
and morality are conceptually separate; that in hard cases when
there are no clear legal rules, judges exercise discretion by ap-
pealing to extra-legal considerations; that these extra-legal
considerations are often utilitarian in character in that they seek
to promote the general welfare rather than individual rights.
Dworkin rejects each one of these claims. He argues that law
consists of principles as well as rules. These principles are moral
principles which confer rights on individuals. In hard cases where
rules do not dictate a result, a judge is still bound by legal prin-
ciples and does not therefore have discretion. Decisions governed
by legal principles enforce the existing rights of individuals, and
hence judges do not create the law: they discover it. Judges
should not decide hard cases on the basis of those considerations
which influence legislators when they pursue policies promoting
collective goals. Individual rights are to be enforced against
considerations of the general welfare. Judicial discretion is
mistaken both as a descriptive thesis about how judges in fact
act in hard cases, and as a prescriptive account of how they ought
to behave. Dworkin has pursued these themes over many years,
and in successive papers, now collected in a book, Taking Rights
opposition to legal positivism as well as his own theory of law.1
He has also applied his theory to topical issues with results that
are recognisably liberal in character, although it is a form of
liberalism without the usual utilitarian underpinnings.
The focus of discussion has been on Dworkin's denial of
judicial discretion, for this is the central issue of legal theory in
the United States, where jurisprudence thrives more than any-
where else in the world. The American legal system revolves
I Ronald Dworkin, Taking Rights Seriously (London: Duckworth, 19m.