The way in which Muhammad received inspiration has been shown in a previous chapter; but Ibn Khaldoun gives such an interesting account of prophetic inspiration that I give the substance of his remarks here. He speaks somewhat as follows.[142] If we contemplate the world and the creatures it contains we shall recognize a perfect order, a regular {152} system, a sequence of cause and effect, a connexion between different categories of existence, and a transformation of beings from one category of existence to another. Then the phenomena of the visible world indicate to us the existence of an agent whose nature is different from that of the body, who is in fact a spiritual existence. This agent, which is the soul, must on the one hand be in contact with the existences of this world and, on the other, with the existences in the next category of superiority, and one whose essential qualities are pure perception and clear intelligence. Such are the angels. It follows, then, that the human soul has a tendency towards the angelic world. All this is quite in accordance with the idea that, according to a regular order, all the categories of existences in the universe are in mutual contact by means of their faculties and on account of their nature. The souls of men may be divided into three classes. The first kind of soul is too feeble by nature to attain to a perception of the spiritual: it has to content itself with moving in the region of sense and imagination. Thus it can understand concepts and affirmations. It can raise itself high in its own category but cannot pass its limit. The souls of the second class are carried by a reflective movement and a natural disposition towards a spiritual intelligence. They can enter into a state of contemplation which results in ecstasy. This is the intuition of the Saints (Auliya)[143] to whom God has given this divine knowledge.