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.

I'm very sceptical about the prospects for 'big' environmental causes - 'saving the planet', halving the world's population, ending the exploitation of animals, and so on - but a person can ask him- or herself how he or she personally may exercise compassion or humility towards animals, vegetal life and so on.

There is no reason at all to think that creatures with very different purposes and concerns would arrive at the scientific image, and no reason at all to accuse such creatures of getting the world wrong - a point that both Chuang Tzu and Nietzsche make when comparing human and animal perspectives.

There is something myopic and stunted in focussing only on the meaning of words and sentences. And this myopia is especially unfortunate when combined with a rather abstract view of a language as a set of elements and rules for combining these. For the result is to divorce enquiry into meaning from attention to the way words - and gestures, facial expressions, rituals and so on - are embedded in practices, in what Wittgenstein called 'the stream of life'.

For me, the existentialists are important critics of 'absolutist' claims, and Heidegger and Merleau-Ponty are, at least in their later writings, also exponents of a doctrine of mystery: Being or the 'well-spring' of everything is, for Heidegger, ineffable, just as what Merleau-Ponty called 'Flesh' is for him.

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'.

It is indeed impossible to describe reality 'in itself', but that does not mean that our lives are answerable to nothing but our own conventions and commitments. They are answerable to a way of things that transcends the reach of our conceptual schemes.