The most striking difference between Christian and Muslim theologies is that while, for Christians, God is a person, Muslims worship an impersonal deity. Despite the importance of this difference for a host of theological issues, it is a difference which has gone largely unnoticed by Christians and Muslims alike. Yet Christians everywhere will affirm that God is a person, while the average Muslim will readily deny this. Theism is often defined by philosophers of religion who work in the Christian tradition in such a manner as to require the belief that God is a person. Thus The Encyclopedia of Philosophy has it that, ‘THEISM signifies belief in one God (theos) who is (a) personal, (b) worthy of adoration, and (c) separate from the world but (d) continuously active in it”. John H. Hick admits that, ‘Theism…is strictly belief in a deity, but is generally used to mean belief in a personal deity”. Richard Swinburne states that a theist is one who believes that there is a God who is a ‘person without a body (i.e. a spirit) who is eternal, free, able to do anything, knows everything, is perfectly good, is the proper object of human worship and obedience, the creator and sustainer of the universe”, and J. L. Mackie, while arguing the case of atheism, endorses Swinburne's definition of theism.