Blimpish claimed that in refuting God, I hadn't refuted any of these four philosophical arguments. I think it is important to explain why these arguments for God are rubbish;
Ontological: This is the argument for God from imagining 'his perfection'. Kant claims that "ontological arguments are vitiated by their reliance upon the implicit assumption that existence is a predicate".
Basically, the very fact you can 'think' there is a God who is perfect, cannot be proof there is. What is 'perfect' anyway? It is indefinable.
Cosmological: This is the 'non-argument' that our very existence, 'means' there must be a God. It 'means' nothing of the sort, if only because it leads to the question 'who created God?'. This argument is obvious nonsense.
Teleological: This is the 'Intelligent design' argument that the complexity of the Universe 'must' mean a designer. If you believe in evolution then this argument becomes rubbish.
Intrinsic Probability: Ockham's razor (also spelt occam's) disproves this argument because it states that the simplest argument is usually correct.
There has been reams and reams written by philosophers on this issue, but there is no need to over-complicate these issues, they are basically very simple. I work on the need to make things as simple as possible. Feynman's diagram demonstrates the power of not over-complicating issues.