Considerable obscurity surrounds the introduction into Islamic thought of the orthodox doctrine that it is God who “creates” the acts of man, whereas man merely “acquires” them (kasaba, iktasaba). The doctrine is sometimes attributed to al-Ash'arī, but in his Maqālāt al-Islamīyīn he himself frequently uses the term in his accounts of the views of other writers. This paper examines the various uses of kasaba and iktasaba in that work to see what light is thrown on the origin and development of the conception.