It would be through individual effort, inspired perhaps by reading Nietzsche's books, that the Overman might emerge, not through social or educational engineering.

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 dis-incumbenced stance is the one people should cultivate, we are told, once they recognize that there is no world beyond the human world. They will, indeed must, have their beliefs and values, but they will recognize that these 'lean upon' - and are answerable to - nothing other than human commitments and purposes. The only fidelity, Rorty remarked, can be to our own conventions.

The garden is as good a symbol as you can find of a dialectic between spheres of experience - of culture and nature - that presuppose one another.

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.

Like Nietzsche's own writings on education, most of mine were relatively youthful ones. Both were inspired by a critical animus against prevailing trends in education: in Nietzsche's case, the production either of 'useless', dry-as-dust scholars or people 'useful' for the needs of an expanding industrial economy; in my case, a similar subjection of education to economic imperatives, but also to ideological obsessions, notably with promoting 'equality'.

Things only 'show up' for us as they do, as Heidegger would put, in and through practical engagements with the world that enable objects to have significance and salience - as hammers, pots, trees or whatever.