I finally finished that excellent book by Peter Watson last night. One last section that I thought deserved to be excerpted:

But there is another – quite different – reason why, in the West at least, the soul is important, and arguably more important and more fertile than the idea of God. To put it plainly, the idea of the soul has outlived the idea of God; one might even say it has evolved beyond God, beyond religion, in that even people without faith – perhaps especially people without faith – are concerned with the inner life.
…Plato has misled us, and Whitehead was wrong: the great success stories in the history of ideas have been in the main the fulfillment of Aristotle’s legacy, not Plato’s. This is confirmed above all by the latest developments in historiography – which underline that the early modern period, as it is now called, has replaced the Renaissance as the most significant transition in history. As R.W.S. Southern has said, the period between 1050 and 1250, the rediscovery of Aristotle, was the greatest and most important transformation in human life, leading to modernity, and not the (Platonic) Renaissance of two centuries later.
For many years – for hundreds of years – man had little doubt that he had a soul, that whether or not there was some ‘soul substance’ deep inside the body, this soul represented the essence of man, an essence that was immortal, indestructible. Ideas about the soul changed in the sixteenth and seventeenth centuries and, as the loss of belief in God started to gather pace, other notions were conceived. Beginning with Hobbes and then Vico talk about the self and the mind began to replace talk about the soul and this view triumphed in the nineteenth century, especially in Germany with its development of romanticism, of the human or social sciences, Innerlichkeit and the unconscious. The growth of mass society, of the new vast metropolises, played a part here too, provoking as sense of the loss of self.
…Here, therefore, and arising from this book, is one last idea for the scientists to build on. Given the Aristotelian successes of both the remote and immediate past, is it not time to face the possibility – even the probability – that the essential Platonic notion of the ‘inner self’ is misconceived? There is no inner self. Looking ‘in’, we have found nothing – nothing stable, anyway, nothing enduring, nothing we can all agree upon, nothing conclusive – because there is nothing to find. We human beings are part of nature and therefore we are more likely to find out about our ‘inner’ nature, to understand ourselves, by looking outside ourselves, at our role and place as animals. In John Gray’ s words, ‘A zoo is a better window from which to look out of the human world than a monastery.’ This is not paradoxical, and without some such realignment of approach, the modern incoherence will continue.