To describe this world is not to describe reality 'in itself', as it is independently of how we regard and describe it.

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 think it's true that for existentialist thinkers, appreciation of what we are - free, makers of meaning, 'issues' for ourselves, and so on - is at the same time a recognition of how we should try to live.

For many years, questions about the meaning of life were dismissed as senseless. We were told that life, not being a word or sentence or anything language-like, can't intelligibly be said to have meaning. An encouraging development in the last couple of decades is a return by philosophers to addressing - as nearly all people do at some time or another - the question of life's meaning.

There are really three players: 'absolutists', for whom it is possible to describe reality as it anyway is; 'constructivists' or 'humanists', for whom there is nothing beyond a world that is relative to human interests and conceptual schemes; and 'ineffabilists', like myself, for whom any describable world indeed exists 'only in relation to man', as Heidegger put it, but for whom, as well, there is an ineffable realm 'beyond the human'.

An abiding and central concern of philosophy and religion alike is the fear that the world is alien to human beings, that nature is, in Hegel's words, 'out and out other' to 'spirit'. It's easy enough to see how 'constructivist' or 'humanist' conceptions are efforts to dispel this fear.

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