In the chapter 'Nonsense du Jour' he discusses an academic paper 'On Bullshit' by Harry Frankfurt (Professor Emeritus of Philosophy at Princeton University). That there should be such a paper is brilliantly giggleworthy. To paraphrase the paraphrasers:
In his essay Frankfurt characterizes bullshit as a form of falsehood distinct from lying. The liar, he says, knows and cares about the truth, but deliberately sets out to mislead instead of telling the truth. The "bullshitter", on the other hand, does not care about the truth and is only seeking to impress:
“It is impossible for someone to lie unless he thinks he knows the truth. Producing bullshit requires no such conviction. A person who lies is thereby responding to the truth, and he is to that extent respectful of it. When an honest man speaks, he says only what he believes to be true; and for the liar, it is correspondingly indispensable that he considers his statements to be false. For the bullshitter, however, all these bets are off: he is neither on the side of the true nor on the side of the false. His eye is not on the facts at all, as the eyes of the honest man and of the liar are, except insofar as they may be pertinent to his interest in getting away with what he says. He does not care whether the things he says describe reality correctly. He just picks them out, or makes them up, to suit his purpose.”
Mooching around the web a bit checking sources, references and bibliographies (for fun I should add, not because I am some kind of fact hound on a quest for the truth) I found this, a paper looking at synonyms for bullshit, one of which is 'bunkum', and a fantastic extract from a Seinfeld script which discusses the philology of the verb 'to debunk':
Elaine: If anyone needs any medical advice, Elaine met a doctor. And he’s unattached.
Jerry: I thought the whole dream of dating a doctor was debunked.
Elaine: No, it’s not debunked, it’s totally bunk.
Jerry: Isn’t bunk bad? Like, that’s a lot of bunk.
George: No, something is bunk and then you debunk it.
Jerry: What?
Elaine: Huh?
George: I think.
Elaine: Look, I’m dating a doctor and I like it. Let’s just move on
It makes you glad to be alive. Then it makes you miss Seinfeld.
