Philosophy today continues to use the tools that Plato did, but it is no less vital for that, argues Anthony Kenny. The author of a recently completed historical survey of the subject, shares his thoughts with Anthony Freeman

Philosophy is not a matter of knowledge but of understanding, or as Wittgenstein put it: "Philosophy is not one of the natural sciences." For Sir Anthony Kenny, whose Philosophy in the Modern World , which is published this month, sees the completion of his four-volume history of Western philosophy, understanding is philosophy's defining characteristic. It is also what makes the relationship between current philosophers and their greatest predecessors fundamentally different from that between, say, today's quantum physicists and Newton.

To deserve the name philosopher, Kenny explains, it is not enough just to study in our own day the topics that Plato or Aristotle studied in theirs. The crucial thing is to do so by essentially the same methods as were available to them - namely, the study of language and reflection on the nature of our own thought. By contrast, contemporary students of zoology and meteorology, topics also explored by Aristotle, find his work of antiquarian interest only because his knowledge base and techniques in these disciplines were so different from their own. This is what marks them out as scientists, not philosophers. Other subjects grow out of philosophy "and set up house on their own", as Kenny puts it, at the point when they acquire uncontentious concepts and have their own distinctive and agreed methods.

Philosophy, meanwhile, continues to deal with the big subjects - being, essence and possibility - in the time-honoured way.

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There are two main reasons, Kenny thinks, why people might turn to a history of philosophy. Some are seeking help and illumination from older thinkers on topics of current philosophical interest; others are more interested in the feel of the intellectual climate of past societies and want to see earlier thinkers in their own context.

This final volume of his history, like the previous ones, caters for both kinds of reader by setting out in the opening chapters a more or less chronological overview of the period, introducing the major players in turn, and then following up with nine topic-oriented chapters. These run the full gamut from logic, via epistemology and aesthetics, to God, the entire book carried along by an enviable combination of authority and page-turning readability.

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Kenny's introduction to philosophy was in the hard school of the Pontifical Gregorian University in Rome, where he studied for the priesthood in the 1950s. Compulsory lectures on Thomas Aquinas were addressed to an international audience of hundreds of students in Latin. Moreover, they dwelt mostly on the professors' personal opinions of Thomism, offering little direct experience of the "Angelic Doctor's" own words. The frustration of these years shows in Kenny's advice to those showing an interest in philosophy now: the best way to learn it is to read the works of the great philosophers of the past.

In view of this, it is perhaps surprisingthat much of his own professional writing consists of introductions, in contemporary terms, to the work of the past heroes he so admires. He modestly attributes this career choice to a belief that, when it came to original philosophical ideas, "I was not able enough to compete with the best of my colleagues", and so could contribute more by helping students and others to engage with the likes of Aquinas, Descartes and Kant. In truth, there is no conflict here, because (unlike the lecturers he endured in his youth) Kenny is the kind of teacher who genuinely introduces his audience to the great minds of the past, rather than imposing himself and his views as a barrier between them.

Among his peers, Kenny is chiefly acknowledged for his work on Aquinas. His ideal here is to treat Aquinas in the same way as Aquinas treated Aristotle, that is, to take him seriously as somebody offering something that is worth considering in its own right and not just to be dismissed as quaint things that people thought hundreds of years ago. It is because he engages seriously with Aquinas's arguments that Kenny is ready to point out where he thinks there are flaws in them; with a great philosopher, he insists, you can learn as much from their mistakes as from where you think they get things right. This follows naturally from his understanding of philosophy as the area where methods and material are essentially unchanging across the generations.

Among 20th-century philosophers, Kenny finds Wittgenstein without equal, noting the failure of anyone since to illuminate the whole area of philosophy as he did. Kenny is saddened that despite a good deal of "Wittgenstein scholarship" going on, the spirit of the Wittgensteinian approach - most of all to the philosophy of mind - has been overshadowed by the narrower scientistic programme, especially in the US. For Kenny, Wittgenstein transcends the alleged divide in 20th-century philosophy between the Anglo-American "analytic" school, which focuses on the logical clarification of thoughts, and the "continental" tradition, which tends to relate philosophical inquiry more to personal, moral or political transformation.

Kenny's secular academic career resulted from his decision, after some years of priestly ministry, that he could no longer continue as a teacher of doctrines and moral precepts about whose validity he was increasingly doubtful. He obtained leave from Pope Paul VI to return to the lay state, and on the strength of his recently published dissertation was offered positions in quick succession at several Oxford University colleges. As well as becoming a distinguished teacher and historian of philosophy, he was, for more than 20 years, at the heart of the British educational establishment, not only holding key posts at Oxford (master of Balliol 1978-89; warden of Rhodes House 1989-99; pro vice-chancellor for development from 1999 until his retirement in 2001) but also spending a period as president of the British Academy. A knighthood came in 1992.

Having finally laid down the burdens of administration, Kenny has in his so-called retirement taken up his pen again and, having produced more than one book a year for the past seven years, appears to be in something close to full-time employment.

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Asked about the current state of philosophy, Kenny regrets the trend towards an inbred jargon-laden "professionalism" in the subject and finds it a cause for unease. Holding as he does that a philosopher has no access either to information or to methods of inquiry that are not open to everybody, he believes strongly that philosophy should be made intelligible to a general public, and he admires Bertrand Russell, in particular, for his gift of combining serious philosophy with accessibility.

Despite its being "full of mistakes and prejudice", he finds Russell's History of Western Philosophy a most readable book and crucially one that gives a feeling of the intellectual excitement of philosophy and of its relevance to practical and political life. In his own four-volume history, Kenny says, he aims to steer a mid-course between the punctilious but dry style of one of his own teachers, the prolific Thomist writer F. C. Copplestone ("the jokes were very few and far between") and the sometimes wayward but undoubtedly entertaining Russell.

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To illustrate his understanding of how philosophy can inform and enlighten work in other disciplines, Kenny refers to another of his recent books, a volume for a series on philosophy and public life, written collaboratively with his economist son Charles.

The subject of the book was happiness, and what philosophy had to offer was a sound structure for thinking about the subject. It seemed to Kenny senior that the economists writing on the subject were getting themselves into contradictions - and consequently some policy disasters - by failing to distinguish three different elements that had made up the concept of happiness through the ages. He identified these as physical welfare, contentment (as a state of mind) and dignity as something that was objective; and Charles discovered that this structure was the thing that enabled him to make sense of the whole picture in a way that reading the economists alone had failed to do.

This has important practical implications. For instance, the World Bank is currently exercised by the question of whether it should go back to concentrating solely on growth, and in the Kennys' book one of the things they argued is that beyond a certain point growth does not contribute to happiness in any significant way.

This is a specific example of how Anthony Kenny sees the role of philosophy in everyday affairs, now and in the future no less than in the past: by making distinctions, resolving ambiguities, and so at best removing the contradictions that impede progress, or at least showing which goals are achievable and which chimerical.

Anthony Freeman is managing editor of the Journal of Consciousness Studies .

Philosophy in the Modern World: A New History of Western Philosophy, Volume 4 by Anthony Kenny is published by Oxford University Press, ?18.99.

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