the reader may be surprised by our emphasis on the similarity of muhammad's teaching to the methods of modern science. the scientific method demands that were one to undertake an investigation, he should suspend his personal views, beliefs and doctrines. it demands that he begins his study by observation, classification, comparison, experimentation, and then draw his conclusions from these scientific observations as premises. a conclusion reached through this method is scientific and, by the same token, it remains susceptible to further scrutiny and investigation. it remains valid as long as further scientific study has not disproved any one of the premises on which it is based. this scientific method is the highest human achievement in the cause of free thought. and yet this very method is none other than that of muhammad, the very foundation of his cause. how did his followers become convinced of it? they repudiated all their previous beliefs had began to concentrate their thoughts on what lay before them. but what was before them? what were the facts of religious life in arabia? every one of the arab tribes had its own idols; but which one was true and which false? besides, within arabia as well as in the surrounding countries, there were christians, jews, sabeans, zoroastrian fire-worshippers, and others who worshipped the sun. whose faith was true and whose false?