It is widely assumed by philosophers that the main task of moral philosophy is to provide a general theory of morality. Moral philosophy will provide us with the correct distinction between right and wrong action, or between good and bad behavior, or between virtuous and vicious character. Right, wrong, good, bad, virtuous and vicious are the central concepts in morality. The job of philosophy is to sort out their meaning and relations. The central concepts are thus a very small set of so-called “thin” concepts.

Some virtues theorists object that this is an unduly narrow approach to the subject. They wish to introduce a richer repertoire, the repertoire of the virtue and vice concepts. For them the task of moral philosophy is to make sense of good and bad character and action in terms of the recognized range of virtues and vices, such as kindness, courage, fairness, honesty and justice. This is indeed an enriched approach – but is it rich enough?

We might go much further. Suppose we were to collect a whole lexicon or thesaurus of moral terminology. How rich would it be? Oddly enough, no-one seems to have done this. I have seen suggestions that it would be quite small. My own amateur attempts suggest otherwise. I have a list of 100 terms for morally wrong actions, including relative rarities such as buck-passing, whitewashing, stalking and racketeering, but not forgetting core concepts such as murder, theft, rape, fraud and assault. Admittedly, we seem to have fewer terms for good actions. But Edmund Pin-coffs (in Quandaries and Virtues) showed that we have a rich repertoire of good and bad character concepts.

This approach might be deemed the “thick” method of doing moral philosophy. It rests on the indisputable idea that we already have a considerable stock of moral distinctions. But what work does it leave for moral philosophy to do? Does it reduce the philosopher to mere stamp collecting? In fact there is much to do, given this idea of moral philosophy. The central task is that of making sense of our moral lexicon. It requires that we interpret the meanings and relations that hold within and between these concepts. It also requires that we set these concepts in the wider context of our other concepts and of the social institutions and practices that employ these concepts.

In fact this “thick” approach is a widely practiced approach to moral philosophy, but one that lacks the status of the general theories and theorists. And few philosophers have attempted to put together a general account of moral concepts, as distinct from a general theory of morality. One exception is the Hungarianborn Australian philosopher, Julius Kovesi. In his 1967 book Moral Notions, Kovesi set out to explore how moral concepts are constructed, how they are used, and how they relate to our other concepts. His main general point is that they are in no way special except in that their content is moral content.

Kovesi’s central idea was what he called the “formal element” of concepts. This idea is somewhat similar to what Wittgenstein meant by the “rule-following” aspect of how we use concepts in practical life. Similar, but not quite the same. A better translation of what Kovesi meant is “the reason why we have the concept”. Concepts are formed because we need to make distinctions. We have a reason to make them. For example, the concept of manslaughter arises from our need to distinguish some kinds of wrongful killing from other kinds. Concepts thus structure what counts as a reason in our shared lives. Concepts are not just forms of rule-following. They have rational force.

Kovesi distinguished the formal element of a concept from its “material elements”. The material elements are the various ways in which the concept can be instantiated. There are innumerable ways in which murders can be committed. Likewise, there are innumerable kinds and examples of tables or games or plants or whatever. At present there may be only 118 known chemical elements, but it is important that the set is not closed – new elements may still be discovered. This openness is a general feature of concepts, Kovesi thought. And this implies that we cannot grasp the meaning of a term simply by listing instances or kinds of the term, even if the list is correct as far as it goes. We need to grasp not just what the list’s members have in common but what would make some additional example a genuine or false example. And to grasp this we need to go back to the formal element, to the reason why we have the concept. A digital book has little in common with a paper-based book but it is still a book, because the formal element is the same.

Kovesi’s argument was intended to break down the distinction between fact and value that has so dominated moral philosophy. Values enter into the formation of our concepts, while “facts” so-called play only a secondary role. There is no defined set of facts that accounts for the meaning of any given concepts. What gives our concepts meaning is the shared values that inform them. Values and reasons go together in structuring the concepts that shape our lives.

Kovesi’s moral philosophy shows why we need a rich repertoire of concepts. Each concept has a role to play. Take one away and our capacity for moral functioning is to that degree weakened. Moral philosophy has to be “thick”. What then of our “thin” concepts? Kovesi had an answer to that question. Some of our thin concepts, good and bad, serve as very high level discriminators. “Good” is the most general term of approbation. Other thin concepts play a role in moral reasoning. “Right” and “wrong” play a part when we are debating about an action that does not fall directly under any of our existing repertoire of concepts. In general the thin concepts play a supplementary role in moral thought, and not a central role, as many moral philosophers assume.

Moral Notions had a strong influence on a few philosophers, and no influence at all on many. To those for whom his work mattered it seems to still matter.

Amongst them are some well-known names: Bernard Harrison, Peter French, Bob Ewin, Jean Bethke Elshtain, and Dennis Patterson. A collection of papers by these authors and others designed to re-introduce Kovesi’s distinctive contribution to moral philosophy has recently been compiled by Brian Mooney and Alan Tapper, under the title Meaning and Morality: Essays on the Philosophy of Julius Kovesi (Brill, 2012). Alasdair MacIntyre once described Moral Notions as “a minor classic of moral philosophy”.