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.

Like Nietzsche, Heidegger also gave up on the prospect that schools and universities would nurture the kind of reflective openness to the way of things that, certainly by the 1940s, he identified with authentic thinking. The authentic person is not the Promethean, iron-willed figure that pops up in Nietzsche, but someone more like the Daoist sages whom Heidegger admired.

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.

What impressed me about Plato and Sartre was their conviction that we should live our lives in the light of big truths about reality and human existence.

The question of meaning goes all the way down: if human life as a whole is meaningless, so is everything that occurs or belongs within it. Since that's not a thought it is easy to live with, there is good reason to search for life's meaning.

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'.

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.