The focus of environmental ethics should indeed be on the virtues and how these inform our relationship to natural environments.

Nietzsche's 'perspectivalism' was expressly directed against the 'laughable juxtaposition of "man and world"'. But 'absolutist' accounts, too, typically try to demonstrate that human beings are integral components of the world these accounts articulate - that, for example, we are simply material bodies subject to the same natural processes as everything else.

The aim of dis-incumbence is a hubristic one, for it requires confidence in the ability of men and women to live in the belief that nothing they do can, in the end, be justified by anything. That's a belief that it is easy to proclaim in seminar rooms or pubs, but not one that people could actually live with.

I was keen to dispel a familiar misunderstanding: that existentialists somehow relish the alienation of human beings from the world. This may have been Camus's attitude, but it was certainly not that of Heidegger, Sartre and Merleau-Ponty, each of whom tried to show that we can only experience the world in relation to our own projects and purposes. The world is initially one of 'equipment', said Heidegger: it is a world of 'tasks', said Sartre.

The main objection to the 'scientistic' claim that physics describes the world as it is in itself is that you 'can't weed out' the human contribution. That is, the scientific image of the world, like any other, is indelibly shaped by our interests, practices and prejudices.

The writing I have in mind and sometimes indulge in myself is concerned, not with plants, mountains or birds as items of scientific description, but with experiences of nature that impinge upon our moods and emotions, enrich our imagination and reveries, and shape our sense of how we stand in relation to the environing world. In a broad sense of the term, this kind of writing is an exercise in phenomenology, an attempt to render the significance that birds, plants or whatever have for us.

The demands of the economy, and more recently those of political correctness and the diktat against ever offending anyone, are not conducive to a classroom or university seminar climate in which genuinely free and critical reflection on how to live prospers.