My experience on this is that there are 3 types of BSers, the know-it-all BSer, the know-nothing BSer, and the all-purpose BSer.
The know-it-all BSer does in fact know quite a lot about a broad range of topics. Problem with this is that he has built his self image around his status as an expert, and thus finds it difficult to ever admit that there is anything he doesn’t know. So when such a situation arises, he copes with it by BSing. Generally such guys pull it off by talking a lot about aspects of the issue that they do know and glossing over those that they don’t.
The know-nothing BSer is the opposite - a guy who knows relatively little about anything. He copes with this by tending to make things up, or, more usually by speaking in vague generalities and hoping no one knows that he really doesn’t know what he is talking about. The problem with this type of guy is that in his ignorance he doesn’t know which things are “acceptable” to not know, and so is afraid to admit that he doesn’t know anything, leading to absurd situations in which he pretends to know about relatively obscure topics.
The all-purpose BSer is someone who knows about as much as anyone else, and has no unique motivation to do this. But some people just have a very loose attitude towards information, and are unable to distinguish between genuine actual knowledge and thoughts that are floating around in their head, or jive that they once overheard or saw somewhere.
) lectures, and the invents classical authors and learned professors to cite in support of his errors.