What does Coelho says about the soul of the world? How does the protagonist succeeds in finding the soul of the world?

The final realization of the book is that Santiago's soul is just a part of the Soul of the World, which is the same as God. This in turn translates in to a much more pragmatic ecumenicist theme in the book - that is to say, that throughout the narrative there is a minimization of the difference between Muslim and Christian, the two religious spheres in which the narrative takes place. The reader is led to understand that since God is one with all of creation, all religions are essentially saying the same thing. Thus, Santiago's initial thoughts about the strangeness of the "infidels," as he first refers to the residents of the city of Tangiers, are quite quickly swept away by his realization that the spiritual concerns of Muslims are very similar to his own. The shopkeeper's concerns about his dream of pilgrimage to Mecca can be identified with any dream that one is afraid of fulfilling.