I think the bishop's argument was shortcircuited by the overly ambitious heading of the talk. Trying to prove "Jesus is our Saviour" in a philosphical discussion is impossible. However, making a strong - even winning - argument for the existence of God, even a personal God, is a different matter, and that talk about 'feeling an inner light' is a very strong argument indeed. We humans have something like a sex-drive towards God: If there were only male men on earth, and they had never seen a woman, they would still be yearning for women. They couldn't describe them. They wouldn't exactly know what it is they desire, but they could give you an idea: "Something gentle, beautiful, that you can take in your arms and in your bed, something you can talk to and sleep with.." etc.
Well, it's kind of the same with this other thing we yearn for, called 'GOD'. And for every yearning there is some kind of satisfaction - that's just an empirical fact: Hunger, Curiosity, Exhaustion. Every lock has its key. Of course, when I find that key, it might be very different from what I imagined, but I will immediately recognize it, because it quenches the exact thirst I was feeling. Only the dimmest Christians (or Muslims, Buddhists etc.) will fail to admit that when God finally reveals himself to them, they will not be surprised. And the 'tooth-fairy' argument would be quite out of place here: Nobody would fall into a state of lifelong depression because his childish fancy for this myth was disappointed. The yearning has to be fundamentally deeper in order to be taken earnestly. The yearning for God is of that nature.
What do we think?