It irks me beyond measure to see and hear the arrogance of this new class of atheists who seem everywhere at the moment, and who appear on the ascendancy culturally. They willingly engage Christians in debate along the manner limned above, and smugly toss away the challenge to their views--even though on the basis of sheer forensics, they've gotten their clocks cleaned. They're heroes to the young, brain-washed, and uninformed, who follow them like lemmings to their inevitable plunge into hell.
Why do these unbelieving, self-inflated blusterers seem bullet proof? I think that as long as the issue is God in general, or even Jesus Christ in particular, these blind guides and their rodent trains will continue to the precipice undaunted. They can be out debated and argued under the table until the cows come home, and it won't change a thing. A change of heart and mind is desperately needed, but it isn't going to come by arguing about things that are outside of themselves.
You see, change is wrapped up in the notion of repentance. Jesus has not come to call those who see no need for repentance but those who do. If any headway is to be made evangelistically with the growing horde of the educated, urbane, and unbelieving, the argument will have to be about man, not God. The man in them has to be humbled, shown that he is sinful, that he may be able to think a noble thought but lacks the self-control to live a noble life, that as a species he is tied up with the death of everything.
If something doesn't snap the pride of man, he marches unheeding into the fires of doom. An awakening must arise in each one, individually, deep inside. Something has to break the gaze upon self, so that the head can turn to see that the Redeemer is near. Christians have attempted to engage the unbelieving with every argument imaginable, and found their punches landing without impact. Perhaps it's time to lead with sin.
It is not like a logical, even a factual argument is going to bring anyone to salvation. That cannot happen apart from that unseen work of the Holy Spirit. Jesus did clue us into what the Holy Spirit is convicting people of, and it's not forensics. So, if one wants to flow with the Spirit, and see their witness have supernatural affect, the effort to concentrate on is to help the unbeliever realize he is a sinner. Apart from that he'll never be saved.