(This is an archived extract from the book Patterns of Power: Edition 2)
The law, as Hart said, has to have an “enduring character”, so it cannot change with every passing whim of politicians (5.1.2). People have to know almost instinctively what the law is if they are to obey it, so it is impractical to change it too rapidly, but at the beginning of the 21st century there is an increasing rate of change in society – particularly with the pressures from pluralism and globalisation. The law exists to serve society's needs and therefore has to (cautiously) adapt as the situation changes.
Society has to find a balance between prescriptiveness and flexibility in the Legal Dimension. As Hart expressed it:
“Two principal devices, at first sight very different from each other, have been used for the communication of such general standards of conduct in advance of the successive occasions on which they are to be applied. One of them makes a maximal and the other a minimal use of general classifying words. The first is typified by what we call legislation and the second by precedent.” 
In this book it is argued that a positivist approach, based upon trying to legislate for every eventuality, is inappropriate in today's world. For many issues an alternative approach is possible: to allow new precedents to be established within existing law, so that the law adapts itself to changes in circumstances.
If legislation is “open-textured”, to use Hart’s term, it is not too prescriptive and can subsequently be refined by precedent, using judicial discretion (5.2.2). There are several reasons for favouring the open-textured approach; for example:
· Simpler drafting is quicker (and cheaper) to produce.
· Open-textured legislation is less susceptible to the need for frequent amendments or the drafting of new laws.
· There is less risk of making errors and leaving loopholes in a mass of prescriptive detail.
· It is difficult for legislation which is flowed down from higher levels of authority to incorporate sufficient flexibility to take account of local cultural differences; prescriptive legislation is therefore inconsistent with inclusivity.
It is desirable for open-textured legislation to include a clear statement of its objectives and to give guidance to the judiciary when establishing precedents, to mitigate the risk of undermining the separation of powers (5.2.8) between the legislators and the judiciary. The objectives can be embodied in the legislation as a preamble, as is often the case in international legislation, or they can be stated separately as principles – as is the case if there is a charter of human rights. Ronald Dworkin provided a closely-argued philosophical case for viewing the law as a coherent whole: including statutes (the “rules”) and those principles that have been agreed, such as a Constitution and human rights.
There is also a need for flexibility in the guidance on the sentencing policy contained in legislation, for similar reasons: to accommodate the pace of change and to allow for local differences. This is an area where politicians may wish to be more prescriptive, for political reasons, but they should take account of costs and also the advantages of flexibility in sentencing – to allow the penal system to achieve its aims, which include rehabilitation of those who have broken the law (5.2.7).
Further flexibility is provided by the decision of whether or not to prosecute. The prosecution service can decide that it is not in the public interest to bring a case against individuals who have acted in a morally-defensible and socially-acceptable manner, even if their actions were strictly-speaking illegal. There have been examples of this approach in British law in relation to the very contentious subject of assisted suicide.
© PatternsofPower.org, 2014
 H.L.A. Hart, The Concept of Law, p. 124.
 R.M. Dworkin gives the example of Judge Earl’s argument, in the case of Elmer, that “since a statute forms part of a larger system, the law as a whole, it should be constructed so as to make that larger system coherent in principle”. This argument was used in giving a ruling that prevented Elmer from inheriting his grandfather’s estate, even though he was the latter’s stated beneficiary, because he had murdered his grandfather. Law’s Empire, pp. 19-20.
 On 20 March 2009, the BBC reported the case of Debbie Purdy’s attempt to get a clear ruling on the legality of her husband helping her to travel to Switzerland (where assisted suicide is legal) so that she could die with dignity. The question of flexibility within the British law was specifically addressed in the article:
"Liberal Democrat peer Lord Carlile said the current system should be left broadly as it is and the law was actually "quite clear".
"There is a law against assisting suicide and there is also an important constitutional discretion which can be exercised so that a prosecution may not be brought if it is in the public interest not to bring it," he said.
Making the law "prescriptive" would make using that discretion more difficult, he said.”
The article pointed out that the discretion not to prosecute had been exercised over 100 times in other similar cases. It was available in May 2014 at http://news.bbc.co.uk/1/hi/uk_politics/7953570.stm.