When Neil MacCormick played the bagpipes at the funeral of his close friend, the Labour leader John Smith, on the island of Iona in 1994, he demonstrated not only his musical skill, but a unique ability to bridge the political divide in Scotland.

As a lifelong nationalist, whose father had established the first National Party of Scotland, he was naturally devoted to the concept of independence — a policy that is anathema to Labour in Scotland. But he was possessed of a gift, amounting almost to genius, for seeing the good qualities in other people and other points of view, and he would never allow party bias to interfere with friendship or alliances; the word hardline was alien to his nature.

This may explain why he did not pursue a conventional political career — he was never elected to Parliament, either at Westminster or Holyrood, though he fought several seats for the Scottish National Party in Edinburgh and Argyll, and served for five years as a distinguished member of the European Parliament.

On the other hand, his influence on the development of nationalism in Scotland, and, more broadly, the intellectual life of the nation, cannot be overstated. He was a member of the national council of the SNP for a total of 12 years, wrote the constitution for an independent Scotland, was a special adviser to the party’s leader, Alex Salmond, and helped to effect its transition from a party of protest to a party of government.

At the same time, as one of the world’s leading experts on the philosophy of law, he contributed works of crucial importance to our understanding of the role played by the law in shaping society.

His twin careers, academic and political, were in fact equal parts of the whole. He believed in the rule of law as a central element of a civilised society, and the law itself as the glue that held it together; but he also knew that practical politics — the business of winning votes and being elected to parliament — were essential if the law was to be properly applied.

He wrote widely and with great authority on his subject, and, only months before his death, delivered the manuscript of the last of three volumes that have changed ideas about the history and philosophy of the law.

In them, he took on one of the great debates that continues to divide legal experts — between the views of H. L. A. Hart and Ronald Dworkin, both Professors of Jurisprudence at the University of Oxford in the 1960s, both holding contrasting views about the concept of the law.

Hart argued that a system of law consisted of primary “rules of obligation”, along with secondary rules which provided their framework; society was driven and shaped by them. Dworkin, by contrast, said that there were certain moral principles that underpinned the administration of the law, and these principles played an important part in influencing judicial decisions.

MacCormick, as a former pupil of Hart, and the author of a seminal biography of him, favoured Hart’s approach, but found common ground between the two protagonists. In his Institutions of the Law (2007), he developed his own theory, which took the debate a crucial step forwards, providing a rigorous analysis of the role of law in society and showing how law creates the conditions for social peace and a thriving economy.

He continued to pay tribute to Hart’s most important book, The Concept of Law. “It is”, he wrote, “a work of international eminence which even its strongest critics have acknowledged as a masterpiece worth at least the compliment of careful refutation.”

The same could well have been said of MacCormick’s own body of work, amounting to a dozen substantial books on the constitution, politics and the law.