Craig, Plantinga, and others have said that the Witness of the Holy Spirit is such a powerful, immediate, and veridical feeling, it provides them with an intrinsic defeater defeater to any counter evidence that might come up that suggests that their God view is not correct.
I thought and prayed about it all day today, and I am now having my own special witness in my heart that is informing me about a transcendental reality. In fact, my experience of the Witness of the Flying Spaghetti Monster in my heart is so powerful, it gives me an intrinsic defeater defeater defeater to their Jesus beliefs.
My point is this. When confronted with the possibility that there could be evidence that would undermine his conclusion that the Christian God exists, or that Jesus Christ is the savior of humanity, William Lane Craig has said that the witness of the Holy Spirit is so powerful and so assuring, and he's so utterly convinced of its veracity, that he has a built in, intrinsic defeater. Prior to even confronting that evidence, Craig has announced that nothing could convince him that he's made a mistake. Furthermore, his access to this special witness of the Holy Spirit is something private that he feels inside his head. How does he know that this special feeling can be trusted? Because it is a very powerful feeling that inspires complete trust in him. How does he know that this feeling is more than just a feeling, it is a reliable indicator of the truth outside of his head? The feeling is a very powerful, assuring feeling that it is accurate about the truth outside of his head. Craig's feeling is the measure of its own reliability, hence "intrinsically justifying" is just a distracting way to say his reasoning is utterly circular.
The point of the Flying Spaghetti Monster Witness example is to show just how ludicrous this story is. What's to keep every other believer in other incompatible divine beings from announcing the same? And what standard would those of us who don't have the feeling use to judge between these reports? If I'm having this feeling, and feels like it's authentic, is that sufficient to establish that it is? Of course not. What if the ardent Spaghetti follower announces that his feeling not only informs him about the authenticity of the FSM, but it also informs him, intrinsically, and incorrigibly, that anyone else who claims to have a intrinsically justifying Witness belief in any other God is wrong? The FSM voice in his head tells him, "If anyone says he's got an intrinsic defeater defeater for his belief, don't worry. I'm giving you an intrinsic defeater defeater defeater, so you can rest assured that you're believing in the one true divine being and all of the rest of them are deluded."
Craig's witness of the Holy Spirit justification for theism, and his intrinsic defeater defeater response to objections is complete silliness obscured by pseudo-epistemological jargon.