‘Is agnosticism necessary?’ examines the responses of agnosticism to atheism. Atheism does not require a defence, rather it is up to theists to convince us that there is a God. If there is room for doubt, then atheism is the rational choice: this is the presumption of atheism — it is the negative position. The arguments against this view are set out. There should be no presumption of atheism, and indeed no presumption of theism either: the initial position should be an agnostic one. Agnosticism is not redundant, but does rest on the relatively weak point that we cannot prove God does or does not exist.