>Accordingly we must say that if a man listens to backbiting without resisting it, he seems to consent to the backbiter, so that he becomes a participator in his sin. And if he induces him to backbite, or at least if the detraction be pleasing to him on account of his hatred of the person detracted, he sins no less than the detractor, and sometimes more.
http://www.newadvent.org/summa/3073.htm#article4
It is obviously sinful to allow a person to backbite if I'm directly involved in the conversation. But is it a mortal sin (or a serious venial sin) if I don't interrupt someone's else conversation when I hear backbiting? When I asked my confessor about correcting others, he said that I need to discern wether it's going to make more good than harm and it seems to me that it would not be mortally sinful, since these people are going to continue as soon as I leave. Also, it doesn't seem to count as "listening" since I don't give my attention or approval to this, so I would only hear it.
Still, I have been wondering wether I'm missing something, so I'd like to know your opinion about this /christian/. Yes, this post was made right after I've heard my friends backbiting someone