The wild diversity of religious doctrines suggests to Kitcher that they are all almost certainly false. Plantinga makes an interesting response:
But even for whole systems: there is certainly wide variety here, but how does it follow that they are all almost certainly false? Or even that any particular one is almost false? Kitcher's book is an exercise in philosophy. The variety of philosophical belief rivals that of religion: there are Platonists, nominalists, Aristotelians, Thomists, pragmatists, naturalists, theists, continental philosophers, existentialists, analytic philosophers (who also come in many varieties), and many other philosophical positions. Should we conclude that philosophical positions, including Kitcher's low opinion of religious belief, are all almost certainly false? I should think not. But then wouldn't the same be true for religious beliefs? The fact that others hold religious opinions incompatible with mine is not a good reason, just in itself, for supposing my beliefs false. After all, if I were to suppose my views false, I would once more be in the very same position: there would be very many others who held views incompatible with mine.
To put it my own way: a philosopher discrediting religion on the ground of doctrinal diversity is a case of the pot calling the kettle black. Philosophers notoriously contradict one another on anything and everything. Everything is up for grabs. What then gives philosophy the right to judge religion?