David Hume puts forward three main objections to the type of cosmological argument offered by Leibniz and Clarke (Hume 1779, Part IX, and the entry Hume on religion). The first is that the notion of (absolutely) necessary existence itself is problematic. Suppose that some being is absolutely necessary—then its nonexistence should be absolutely inconceivable. But, says Hume, for any being whose existence we can conceive, we can also conceive its nonexistence, and thus it isn’t a necessary being