The approach to the philosophy of mind that has been adopted in this book does not attempt to demarcate a special domain of mental phenomena. Instead, the fact of presence – the “There is … ” – in its several dimensions has set the agenda for this inquiry, and the progressive differentiation of the concept of what there is – that is, of the world – has replaced the analysis of states of mind and internal representations. As a result, at the point that has now been reached, a picture has emerged that is rather like the one Wittgenstein discusses in the Tractatus – a picture of the world in which there is no place for “the subject,” – or, rather, in which it is at best “the limit of the world.” In this vein, Wittgenstein remarks that “from nothing in the field of sight can it be concluded that it is seen from the eye”; and he adds that “solipsism strictly carried out coincides with pure realism” because “the I in solipsism shrinks to an extensionless point and there remains the reality co-ordinated with it.” Although Wittgenstein goes on to speak of what he calls a “metaphysical subject” that must be conceived in non-psychological terms – not as “a part of the world“ and not as “the human body or the human soul of which psychology treats” – this seems to mean mainly that the only “subject” he is prepared to recognize is one conceived as “the limit of the world.”