Besides this, they deny that God has attributes, and maintain that he knows by his essence only and not by means of any attribute accessory to his essence. In this point they approach the doctrine of the Mutazilites, doctrines which we are not obliged to condemn as irreligious. On the contrary, in our work entitled, "Criteria of the Differences Which Divide Islam from Atheism," we have proved the wrongness of those who accuse of irreligion everything which is opposed to their way of looking at things. (5) _Political Science._ The professors of this confine themselves to drawing up the rules which regulate temporal matters and the royal power. They have borrowed their theories on this point from the books which God has revealed to his prophets and from the sentences of ancient sages, gathered by tradition. (6) _Moral Philosophy._ The professors of this occupy themselves with defining the attributes and qualities of the soul, grouping them according to genus and species, and pointing out the way to moderate and control them. They have borrowed this system from the Sufis. These devout men, who are always engaged in invoking the name of God, in combating concupiscence and following the way of God by renouncing the pleasures of this world, have received, while in a state of ecstasy, revelations regarding the qualities of the soul, its defects and its evil inclinations. These revelations they have published, and the philosophers making use of them have introduced them into their own systems in order to embellish and give currency to their falsehoods. In the times of the philosophers, as at every other period, there existed some of these fervent mystics. God does not deprive this world of them, for they are its sustainers, and they draw down to it the blessings of heaven according to the tradition: "It is by them that you obtain rain; it is by them that you receive your subsistence." Such were "the Companions of the Cave," who lived in ancient times, as related by the Koran (xviii.). Now this mixture of moral and philosophic doctrine with the words of the Prophet and those of the Sufis gives rise to two dangers, one for the upholder of those doctrines, the other for their opponent.