This "professor without a brain"-story sounds very much like a 19th century argument to me. It would be the most likely period in time where a "scientificist" would try to disprove (does he really?) the existence of an all-powerful god, or at least show the contradictions of
His nature. Saint Augustine already did that in the 5th century.
The moral philosopy branch hasn't come up with scientific replacements for Christian morals in our culture. How could they - if Christian values were somehow encoded in the world, so to speak, wouldn't all scientists be Christians by definition, whether they believed in God and Jesus or not?
God(s) may or may not exist, human beings do exist, and so does the human condition. Moral standards are created by us as we go along. If our culture changes its values, so do the patterns of accepted behavior. That's why moral standards differ from time to time and culture to culture - Christian No.2 in the argument tries to equate them with hot and cold, black and white, you either have (his kind) of morality or you have none. We have a basic set of intercultural commands and taboos - don't lie, honor your parents - but we don't seem to agree across the globe that we shouldn't kill animals for sport, abortionists to save lives, etc.
I'd rephrase the God-question in practical terms as:
Is there a reason to believe something good will happen to me when it's unlikely?
As they say, in the trenches, everbody learns to believe in God (well, not everybody). I've felt the need to imagine Jesus, or E.T., walking beside me when I felt very alone and the whole world against me. Unfortunately, I'm not very good at it, and I haven't touched popular philosophy (self-help books

) since I read a pile of the stuff years ago. I don't have one mode of thinking that will help me anytime, anywhere, except that good things happen. They just do.
As for the tired old argument that there's either God's plan for us or pure "randomness" - it's not random in any way we would notice, since we don't experience the other universes where we wouldn't exist. It happened, the Big Bang. Just like that. I'd call this sort of randomness a miracle.