The ambiguity of the word ‘nature’ is so remarkable that I need not remark upon it. Except perhaps to emphasise that this ambiguity — scarcely less apparent, as Aristotle long ago pointed out, in its Greek near-equivalent physis — is by no means a merely accidental product of etymological confusions or conflations: it faithfully reflects the hesitancies, the doubts and the uncertainties, with which men have confronted the world around them. For my special purposes, it is enough to say, I shall be using the word ‘nature’ in one of its narrower senses — so as to include only that which, setting aside the supernatural, is human neither in itself nor in its origins. This is the sense in which neither Sir Christopher Wren nor St Paul's Cathedral forms part of ‘nature’ and it may be hard to decide whether an oddly shaped flint or a landscape where the trees are evenly spaced is or is not ‘natural’. The question I am raising, then, is what our attitudes have been, and ought to be, to nature in this narrow sense of the word, in which it excludes both the human and the artificial. And more narrowly still, I shall be devoting most of my attention to our attitudes towards that part of nature which it lies within man's power to modify and, in particular, towards what Karl Barth calls ‘the strange life of beasts and plants which lies around us’, a life we can by our actions destroy.