This extraordinary vitality of the Ṣūfī restatement of Islam, however, is explained when we reflect on the all-embracing structure of Ṣūfīism. The semitic formula of salvation can be briefly stated in the words, "Transform your will",--which signifies that the Semite looks upon will as the essence of the human soul. The Indian Vedantist, on the other hand, teaches that all pain is due to our mistaken attitude towards the Universe. He, therefore, commands us to transform our understanding--implying thereby that the essential nature of man consists in thought, not activity or will. But the Ṣūfī holds that the mere transformation of will or understanding will not bring peace; we should bring about the transformation of both by a complete transformation of feeling, of which will and understanding are only specialised forms. His message to the individual is--"Love all, and forget your own individuality in doing good to others." Says Rūmī:--"To win other people's hearts is the greatest pilgrimage; and one heart is worth more than a thousand Ka‘bahs. Ka‘bah is a mere cottage of Abraham; but the heart is the very home of God." But this formula demands a _why_ and a _how_--a metaphysical justification of the ideal in order to satisfy the understanding; and rules of action in order to guide the will. Ṣūfīism furnishes both. Semitic religion is a code of strict rules of conduct; the Indian Vedanta, on the other hand, is a cold system of thought. Ṣūfīism avoids their incomplete Psychology, and attempts to synthesise both the Semitic and the Aryan formulas in the higher category of Love. On the one hand it assimilates the Buddhistic idea of Nirwāna (Fanā-Annihilation), and seeks to build a metaphysical system in the light of this idea; on the other hand it does not disconnect itself from Islam, and finds the justification of its view of the Universe in the Qur’ān. Like the geographical position of its home, it stands midway between the Semitic and the Aryan, assimilating ideas from both sides, and giving them the stamp of its own individuality which, on the whole, is more Aryan than Semitic in character. It would, therefore, be evident that the secret of the vitality of Ṣūfīism is the complete view of human nature upon which it is based. It has survived orthodox persecutions and political revolutions, because it appeals to human nature in its entirety; and, while it concentrates its interest chiefly in a _life_ of self-denial, it allows free play to the speculative tendency as well.