 According to Harbour, atheism is "the plausible and probably correct belief that God does not exist", while theism is "the implausible and probably incorrect belief that God does exist", and anyone who cares about the truth should be an atheist.Harbour makes his case on the basis of two fundamental worldviews which he labels the Spartan Meritocracy and the Baroque Monarchy.Worldviews are the ways in which we look at and try to explain the world around us; as a result, the validity of our worldviews is extremely important because it determines the validity and reasonableness of our beliefs.