This debate is about as informal as they get, but doesn't suffer for it. Both speakers are highly articulate and well grounded in the designated subject matter, which is the existence of god and the problem of evil.
Plantinga leads off with a basic restatement of the logical form of the problem of evil and notes that the philosophical community has more or less moved on to the evidential problem of evil. He goes on to claim that some of the classical arguments for god (e.g. cosmological and fine-tuning arguments) provide some evidence for the existence of a creator, and that such evidence should be weighed against the evidential problem of evil. Such arguments may be evidentially relevant to the amoral creator god of deism, but cannot be helpful as evidence for the all-loving god of classical theism.
He eventually gets around to his own defense against the problem of evil, wherein he invents the idea of “no-see-ums” and posits the question of “whether god’s reasons are more like no-see-ums or more like Saint Bernard’s [dogs].” This is particularly ironic way of stating the problem since the latter is an actual canine, while the former is merely a clever concept made up by an apologist for the sake of illustration and persuasion. Um...yeah.
Plantinga goes on to recall the story of Job, in quite some detail, which also strikes me as an odd move, given that the moral of that peculiar story is that if God has any good reasons for allowing evil, they are known only to God (and possibly Satan) but not revealed to humankind. This is not exactly encouraging to the field of theodicy as a theological enterprise.
Nonetheless, Plantinga asserts that there must be good reasons that God permits evidently gratuitious suffering, and states on account of these unknown reasons, "I continue to believe in God and his goodness, and am entirely rational in so doing." He goes on to attempt a theodicy of his own, by providing reasons which might be part of the package of unknown reasons, and they are as follows: The key doctrines of Plantinga's religion (e.g. incarnation, resurrection, atonement) are incomparably good. Therefore, any world in in which Plantinga's religion is true is better than worlds in which it is not true. Therefore, the problem of evil isn't really a problem at all. Seriously, that's his argument. If Plantinga begged the question any harder than this, he'd be ticketed by the thought police.
At any rate, the conversation starts to get geniunely interesting and insightful when Gale takes the stage around 36 minutes in, and starts throwing out questions and having an interchange of ideas. I'll leave it to the listener to judge, but it seemed to me that Gale did a better job of asking difficult questions than Plantinga did of answering them.
Overall, this debate is worth watching. Share and enjoy!