"I began to examine the objects of sensation and speculation to see if they could possibly admit of doubt. Then, doubts crowded upon me in such numbers that my incertitude became complete. Whence results the confidence I have in sensible things? The strongest of all our senses is sight,--yet if we look at the stars they seem to be as small as money-pieces--but mathematical proofs convince us that they are larger than the earth. These and other things are judged by the SENSES, but rejected by REASON as false. I abandoned the senses therefore, having seen my confidence in their ABSOLUTE TRUTH shaken. Perhaps, said I, there is no assurance but in the notions of reason? ... that is to say, first principles, as that ten is more than three? Upon this the SENSES replied: What assurance have you that your confidence in REASON is not of the same nature as your confidence in US? When you relied on us, reason stepped in and gave us the lie,--had not reason been there you would have continued to rely on us. Well, nay there not exist some other judge SUPERIOR to reason who, if he appeared, would refute the judgments of reason in the same way that reason refuted us? The non-appearance of such a judge is no proof of his non-existence.... I strove to answer this objection, and my difficulties increased when I came to reflect on sleep. I said to myself: During sleep you give to visions a reality and consistence, and on awakening you are made aware that they were nothing but visions. What assurance have you that all you feel and know does actually exist? It is all true as respects your condition at the moment,--but it is nevertheless possible that another condition should present itself which should be to your awakened state, that which your awakened state is now to your sleep,--SO THAT, AS RESPECTS THIS HIGHER CONDITION YOUR WAKING IS BUT SLEEP." Over and over again Alwyn read these words and pondered on the deep and difficult problems they suggested, and he was touched to an odd sense of shamed compunction, when at the close of the book he came upon Algazzali's confession of utter vanquishment and humility thus simply recorded: "I examined my actions and found the best were those relating to instruction and education, and even there I saw myself given up to unimportant sciences all useless in another world. Reflecting on the aim of my teaching, I found it was not pure in the sight of the Lord. And that all my efforts were directed toward the acquisition of glory to myself. Having therefore distributed my wealth I left Bagdad and retired into Syria, where I remained in solitary struggle with my soul, combating my passions and exercising myself in the purification of my heart and in preparation for the other world."