Each profession or task in society has a role in society. That profession exists — and, in the end, is paid for by the public — because of some service it performs. Accountants exist because companies can't run their businesses without them, and therefore the service the companies give to society wouldn't get done. They are employed as auditors to make sure that the company is being run honestly, and genuinely for the purpose which society permits it to pursue. That is, accountants have a role within a company or within society at large which serves some purpose, has some point for the good of society. We need flourishing and honest businesses, and so we encourage people to be accountants to develop and exercise certain skills.

In the same way, we want there to be forests and so we agree to pay people who have the skills needed to preserve them. There's a point to this profession within the wider context of society as a whole.

What happens in the case of the fraudulent auditor and the forest ranger who starts a fire? They are using their special skills, which were acquired and are supported for a special purpose, for a different purpose – for the opposite purpose, in fact. The auditor is there to protect society from fraudulent businesses by revealing their fraud: the forest ranger is there to protect the forests that society values. And in both cases, they are able to do what they shouldn't more effectively because of their special skills.

This is a point made long ago by Plato, in the first book of his book The Republic. A locksmith, an expert in locks and keys, is the best person to look after your money for you – but is also the best person to steal it quickly, effectively, and without leaving incriminating evidence. Actually he went on to say that for this reason it looks as if the best person to look after your money is a clever thief.

The point of this is that knowledge, whether expert knowledge or the ordinary knowledge we all have, is not enough. It can be used well or badly – it can be directed towards the right purpose or away from it. So in our society, or in any society, don't necessarily need more expert skills – what we need is honest people, good citizens, who become experts. And probably we won't get them by having more regulations to control the experts — the experts are going to be the ones who are going to be able to find the smartest ways to get round the regulations, or to break them without getting caught. Or we may end up with another level of experts, experts on regulating experts, and if this new level of experts aren't honest people, they'll be able to use their own level of expertise dishonestly. What all of us need to do is to examine ourselves and the people we live and work with, and see whether our own practices are truly directed to the true purposes of the profession, within the pursuit of the good of society.

Christopher Martin teaches philosophy at the University of St Thomas in Houston, Texas. Email: martincf(at)stthom.edu