There are certain metaphysical theories which present a view of the world and of the position of human-beings within it which have seemed attractive or at least impressive to many irrespective of the arguments that are marshalled in their favour. That is certainly true of Schopenhauer. His identification of the inner nature of reality with the will, and the conclusions which he drew from this as regards the nature of human-beings and their place in the world, have seemed striking and perhaps even illuminating to many thinkers, not all of whom have been philosophers in the most obvious sense and not all of whom have had much concern for the underlying argument that led Schopenhauer to his conclusions. It is in this way too, perhaps, that certain of Schopenhauer's ideas have become well known—his emphasis on the will to live, his pessimism and his views on suicide, and his thoughts about human nature and about sex that have been seen as something of an anticipation of Freud. In recent times attention has also been directed to his influence on Wittgenstein. In all these respects, however, it is Schopenhauer's ideas that have been influential, rather than the argument that underlies them. Indeed it is sometimes said that Schopenhauer was not a very systematic thinker at all. If that seems true it is so in the sense that Kant too has seemed to some unsystematic in the details of his argument. That does not mean that the main structure of the argument is not clear. So it is with Schopenhauer.