So stellt der satz den Sachverhalt gleichsam auf eigene Faust dar.

Foreword. Towards the end of this paper I refer to the work of A. J. Smith who died suddenly on 11 December 1991. His last book, Metaphysical Wit, was published in January 1992 by Cambridge University Press. I would like this paper to be thought of as a small tribute to the man and his work.

There is in Texas an area known as ‘the Big Thicket’. It is an area of impenetratable swamp and woodland. Once, long ago, I heard an American philosopher singing about Wittgenstein's Tractatus. His song had the refrain ‘O the Tractatus is a big thicket’. The general idea was that philosophers, like runaway slaves of old in Texas, had disappeared into it never to be heard of again. I am going to risk it in this paper. But I do hope to emerge with something relevant to say about the theme of this series of lectures: the impulse to philosophise.

What I have to say about the Tractatus is set in the general background of how it should be read in relation to Wittgenstein's Philosophical Investigations. In his preface to this later work he wrote