This is the text of my OBO entry on arguments for the existence of God.

General discussion of ontological arguments. (Extended the discussion of ontological arguments in the then current version of my SEP entry on ontological arguments.).

The Evil-god challenge attempts to undermine classical monotheism by contending that because belief in an omnipotent, omniscient, omni-malevolent God (the Evil-god hypothesis) is similarly reasonable to belief in an omnipotent, omniscient, omnibenevolent God (the Good-god hypothesis), the onus is on the classical monotheist to justify their belief in the latter hypothesis over the former hypothesis. This thesis explores the Evil-god challenge by detailing the history and recent developments of the challenge; distinguishing between different types of Evil-god challenge; responding to several (...) prominent objections to the challenge; and applying the challenge to philosophical arguments for the existence of God. I also evaluate the efficacy of parallel arguments as a whole, with a view to determining the parameters of the Evil-god challenge by laying out exactly which theistic positions are irrevocably undermined by it. I conclude that the Evil-god challenge effectively damages several arguments for the existence of God and, in cases where it does not straightforwardly do so, it nevertheless reduces the Good-god theist’s belief to one or more intuitions. (shrink)