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.

I don't think we should just 'muddle through' and ignore the question of life's meaning. Or better, perhaps, I don't think it is a question that can be ignored once the business of asking about the worth and significance of what one is doing - one's work, one's pleasures, one's ambitions and so on - has got going. You can't at any point stop the urge to ask Tolstoy's questions, '... and then what?', 'What's the point of that?'.

It's one thing to assent to propositions like 'The way of things is ineffable', and quite another to internalise what it is being gestured at by such propositions, to get a sense or feel for mystery. For me, at least, it is in and through ways of engaging with nature that this sense is intimated. These ways include being in the garden.

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.

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.

As for the meaning of gardens, particular gardens may have, of course, all sorts of different meanings - emotive, historical, emblematic, religious, commemorative, and so on. But I think that good gardens all signify or exemplify an important truth about the relationship of culture and nature - their inseparability.

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.