Mill's words resonate strongly today when so much public debate is between rival tribes who have erected ideological defences against any possible intellectual challenge and stay cocooned within their own comfortable echo-chambers. When minds are closed to opposing argument, even sensible opinions lose rational justification and degenerate into mindless "dead dogma". Think climate change or tax cuts.

Reasoned dissent is a particularly valuable asset within the public service. In their policy-advising role, public servants are meant to act as a rational counterpoise to the more partial motivations of politicians through their willingness to question received assumptions and evidence. Conversely, if public servants lapse into their own unthinking consensus, they are betraying their own professional mission.

According to recently retired public service commissioner John Lloyd, many Australian Public Service staff have fallen into this trap. In his valedictory address sponsored by the Institute of Public Administration Australia, Lloyd warned of the dangers of APS "groupthink" dictated by political correctness and stressed the importance of diversity of views and opinions that contribute to good policy advice.

Many public servants hearing these remarks will probably have written them off as typical of Lloyd's right-wing prejudices and not worth bothering about. What else would you expect from a member of the Institute of Public Affairs? By reacting in this way, however, they might simply be confirming the accuracy of Lloyd's comments. So imbued are they with public service groupthink that they are incapable of treating any right-wing criticism seriously.

At the very least, Lloyd raised interesting questions. To what extent is the APS subject to politically correct groupthink (or "progressive consensus", to use a politer term)? How far does this impinge on its capacity to offer alternative governments impartial advice? How far is the APS's prized political neutrality a cover for a definite ideological world view?

These are large issues that can be left for another day. The main point is that Lloyd, though in many ways an inappropriate choice for commissioner and the target of frequent criticism in the pages of the Informant and elsewhere, did have a clear virtue: he was unafraid to challenge accepted Canberra wisdom. He thus offered the locals the opportunity to critically re-examine their own ingrained beliefs, which are often closer to Mill's dead dogmas than to living truths.

One set of assumptions concerns the differences between the public and private sectors, particularly in their ethical dimensions. Many people who have made their careers as public servants tend to think of the public sector as governed by quite distinct values and procedures, radically different from those found in the private sector, particularly the for-profit commercial sector. There may be a few organisational characteristics in common, but the differences are predominant. Some outsiders, however, see the sectors as largely similar in structure, apart from a few distinguishing features due to the unique legal and constitutional purposes of government. Lloyd was in this second camp (essentially similar though partly different) and took every opportunity to tell public servants they had much to learn from private-sector practice.

One example was his sponsoring, in 2016, of a report on the merit principle by a leading businesswoman, Sandra McPhee. The report's purpose was to argue that the merit principle is not unique to the public sector but is also found in the private sector, and so should not be seen as a special, distinguishing feature of the public service justifying lengthy and time-consuming processes. The argument carries some weight. Merit appointment certainly occurs in some parts of the private sector, particularly large, bureaucratic organisations. In addition, government organisations could usefully follow some private-sector practices in streamlining some of the more cumbersome procedures associated with appointments.

However, the rationale for the merit principle in the public sector is significantly different from that in the private sector. Commercial companies can choose to appoint by merit if they think it will enhance their performance, but are not obliged to. Indeed, many private organisations successfully follow the principles of nepotism and cronyism without provoking adverse comment. In the public sector, merit and the accompanying prohibitions on cronyism and nepotism are legally binding obligations imposed on managers whether they like them or not.

In this way, the McPhee argument, though ultimately unconvincing as it stands, can be seen to help clarify our thinking about the merit principle in the APS and the extent to which it is genuinely distinct from private-sector practice.

Similar debates between the two positions (essentially different but a bit similar, and essentially similar but a bit different) have often arisen over the general issue of the supposed uniqueness of ethical values. Again, the answers are not straightforward. From a public-sector perspective, the notion of "public-service ethics" seems to imply ethical values that are distinctive to the public sector, including not only the public-service conception of merit appointment but also other government-related values, such as political neutrality and impartiality, public accountability, due process and fair treatment of citizens. These values are all anchored in the principles of liberal-democratic government and are sometimes known as "classic" or "core" public-service values.

However, there are some ethical virtues, such as honesty, integrity and legality, which belong in any comprehensive list of public-service values but are not exclusively public in application. These values are also relevant to the non-government sectors and figure prominently in private-sector codes of conduct. From a business perspective, any attempt by the public service to lay sole claim to such ethical principles will always appear narrow-minded and sanctimonious. At the same time, some organisational or managerial values, such as efficiency, effectiveness and innovativeness, which have been particularly associated with the private sector, are increasingly emphasised in government as well. For example, the list of APS values in the Public Service Act begins with the statement that "the APS is professional, objective, innovative and efficient", a somewhat awkward compilation of traditionally public-sector and managerial values.

The extent of overlap between values in the different sectors has been the subject of academic research by scholars in the Netherlands, the source of much interesting recent research in public administration (see, for example, "What's valued most? Similarities and differences between the organisational values of the public and private sector", Public Administration 2008, by Z. Van Der Wal and others). A survey of more than 1000 public service and business managers asked respondents to select the five most important values from a preselected list of 20 values. There were a few marked differences between the sectors: public servants gave more weight to lawfulness, incorruptibility and impartiality, while businesspeople especially stressed profitability and innovativeness. But the similarities were more numerous. Of the 10 values most widely endorsed by managers in each sector, seven were common to both sectors: accountability, effectiveness, efficiency, incorruptibility, reliability, expertise and impartiality.

Admittedly, the apparent agreement may hide some important differences. For example, accountability, though universally valued, has markedly divergent implications in the two sectors. Nonetheless, the extent of overlap is significant and underlines the similarity of ethical principles governing organisational practice regardless of the sector to which an organisation belongs.

Public servants have an understandable tendency to focus on the uniquely public aspects of their ethical framework and to ignore the experience of those with a private-sector background as irrelevant. Lloyd's tenure as public service commissioner served to challenge this complacent myopia. He may have been misguided in some of his views but, at the very least, he should be credited with livening up debate.

Richard Mulgan is an emeritus professor at the ANU's Crawford school of public policy. richard.mulgan@anu.edu.au