I do believe in the existence of God, but I do not believe in any of these arguments. I not only think them to be unsound, but I think they are in danger of idolatry, for they invariably replace ones faith in God with a faith in the premises of those argument. Just because something is true doesn’t mean an argument for it is valid, and the premises of such an argument may in fact be false.
Cosmological argument: The principle flaw is that the need for something upon which the existence of things depend does not require it to be God. Atheists have no problem making the laws of nature that upon which the existence of things depend. Both theist and atheist make these an exception to the rule, theists saying that God’s existence doesn’t depend on anything and atheists saying that the existence of the laws of nature do not depend on anything.
Fine tuning argument: Probabilities which cannot be calculated are empty rhetoric, and we have no way to calculate the probability that the universe could have been different than it is. Furthermore just because life of our sort couldn’t exist in a universe different from our own doesn’t mean a different sort of life couldn’t exist in that universe. Also atheists respond with the idea of a multiverse, where all possible universes exist and naturally we must be in one where life is possible.
Moral argument: The above arguments are simply logically unsound but this argument is morally unsound. It is based on an authoritarian notion of morality which is only suitable for toddlers. But in a changing world, mature adults require a morality based on reasons which they can apply to new situations and a morality dictated by some authority (no matter how divine) particularly in ancient documents is simply inadequate. Furthermore we have every indication from science that morality is an evolved instinct of social animals and required for cooperation which is one of the most successful survival strategies to be found in evolution (amply demonstrated in many different species).
So if I do not believe in any of these arguments, then why do I believe? My reasons are found here.