Only on matters of theology, why would you need to know theology (for example) to explain how there is a pun in John that only works in greek?
Please note that I didn't say you have to know theology in order to argue with Creationists. If you can disprove an idea via another school of thought, that's perfectly fine--provided it's the actual idea, not a cartoon of it. (I'm not saying you're arguing against cartoon versions, just that that's the criteria.)
...as the adage has it one can't reason out something that reason didn't put in.
I don't get the relevance here. One common theist accusation is that atheists don't know theology. We are, to their minds, ignorant of the topic. If you demonstrate that you actually know the topic, but still disagree, they lose that argument.
I think the members of a given religion came to their belief and faith via reason and knowledge of that religion and it's usually esoteric theology will be a very small minority.
I agree. That's one reason I find an understanding of theology to be useful--it demonstrates that the theist themself is ignorant of their religion 9 times out of 10. ANTPogo is a fantastic example of thisconcept in action.
It can be a useful tool but I think claiming superior knowledge of someone's beliefs and explaining what they "really" believe hardly sets up a good playing field to challenge the person's beliefs.
That's not what I'm doing. I'm merely saying that ONE of the reasons to understand theology is in order to demonstrate that they don't actually agree as much with their religion as they think.
The main reason, of course, is to show that you've actually given their side a fair hearing, and have actually considered what they have to say. If you're unwilling to do that, you come off as a beligerant dogmatist, and the conversation shuts down immediately. It's much better to say "Well, I've considered that argument (or a similar one) and here's my response" than to say "That's just theology, and isn't relevant."
Would it be better to say when you are using the word "theology" you are talking about the doctrine, the dogma and so on rather than the "how many angels can tweet" type of "academic" study that I associate with the word "theology"?
I'd say yes, with one caveat.
Sic et Non is a theological text addressing how one should go about considering the problem of God. The Rules of St. Benedict include theological discussions regarding the proper way to live as a monk (remember, monks were attempting to create a slice of Heaven on Earth). Dante's Paradisio includes an overview of some pretty deep theology. Aquinus's proofs, for all their flaws, are a serious attempt at addressing known problems. And so on.
My point is, theology isn't just about doctrine and dogma--it's also about the consequences of doctrine and dogma. It's theory and practice of religious beliefs. To a theist, it's as vibrant and real a field of study as astronomy or theoretical physics, and every bit as practical.
But yeah, the "academic" questions like "How many angels fit on the head of a pin?" aren't included. Some people go a bit nutty, and you can't blame the field for that. Physics has perpetual motion, geology has YEC, theology has angles dancing on pins. The abuse doesn't negate the use.