Know thine enemy
I guess a military analogy would be appropriate. When going into battle, it's important to not only know what offensive weapons an enemy has, but what defences there are as well. So what that means for me is regardless of whether I'm on the offence or defence is that I need to know whether I have the defences to properly counter any attacks and that I have strong enough weapons myself that I can pierce my opponents defences. In the context of debates, it means not only do I have to be able to effectively argue my case, but I have to argue it in such a way that reaches through to them.
The argument about Stalin being an atheist or that what happened in Soviet Russia was done in the name of atheism is something I'm not accustomed to. I first came across it when reading The God Delusion. Firstly I didn't know that Stalin was an atheist, or why it matters what his beliefs were - he was a tyrant who did what he could to fortify power. How that has to do with the notion that God is an incredulous concept I'll never understand. But it's a popular argument so knowing how to counter it should be a vital part of an argument arsenal. From what I can gather, the argument is meant to show the dangers of an atheist society though to me it just speaks volumes for the problems of totalitarianism. Stalin used the church when it suited his own ends and attacked it when it didn't. His actions were a profound human tragedy that can not be adequately expressed in words, but to link that to atheism seems nothing more than a tenuous link for a desperate.
The person who decided to contact me was obviously a fan of Lennox, so it would make sense that his personal reasons for belief are similar to that of Lennox - that God is a source of justice. So if that is the case, the appeal against atheism on a societal base would make sense. So in hindsight if I knew what I was up against, I would make sure I could cover the evolutionary origins of morality, talk about the societal role in dictating behaviour, how justice arises and plays a part in society, and talk about societies as a whole where certain extremes arise. So when I move away from strong science and into sociology, I do hit a wall. Does this mean that I'm conceding defeat? No. Quite simply the arguments along the societal line are irrelevant to my arguments of why I don't believe in God. Even if society is better off with belief in god than without, it doesn't make the existence of a god more likely. As Voltaire spoke:
Si Dieu n'existait pas, il faudrait l'inventer. (If God did not exist, it would be necessary to invent him.)
When in an open argument, there is no real way of knowing what your opponent is going to spring on you. Likewise there is no real way of knowing how responses will come to seemingly reasonable arguments. One could have all the facts and construct an elaborately succinct argument and simply have it ignored. I've had that happen multiple times when talking about the fossil record to creationists, though in those instances it was a case of pushing shit uphill.
It really was perplexing when the person I was discussing with claimed that he had pushed me into a corner and countered all my arguments. I don't feel it's personal arrogance, I have been challenged many times where I have been pushed into a corner and this did not at all feel like one of those times. Indeed if he took a minute to even ask why I don't believe and then addressed those points, then maybe I could see where he was coming from. For a message initially titled "Listen and learn" it seemed like the person did not for an instant want that same position personal improvement. Instead he was happy to rely on his own knowledge even when it was manifestly false (such as his definition of atheism.)
Without even bothering to understand where I was coming from, how was he ever going to reach me? Likewise without knowing his reasons for belief in a god, how would I reach him? I could read theist text after theist text, listen to apologists, and still I'd only have arguments that if I threw them out there could only apply to certain people. This has understandably made me quite cautious to go on the attack. I play chess in much the same manner, rarely will I go on the attack against an unknown opponent, rather I take a cautious approach and watch for mistakes / opportunities. Of course chess has set rules so you won't see people trying to use their knight like a rook, so the analogy breaks down at that point.
I've learned from this that it's more than just fact memorisation that comes along with making a successful argument. I've got to be able to communicate my ideas in a way others can understand rather than using the sledgehammer approach I so often employ. By seeing someone come after me, I've glimpsed at the trappings one can easily fall into without a proper awareness of an opponent's position. I've read Dennett talk of writing a successful argument, in where you first take an opponent's position and rephrase it in such a manner so that they can see something insightful from it, and only then can you go about dismantling it. It's a tough standard to live by, but the more I see of communication on matters of disagreement, the more I see merit in Dennett's way of thinking. The key is understanding and without that one is lost.