How would you define bullshit? How would you distinguish it from, say, lying, or telling falsehoods, from humbug, from deception, from accidental or deliberate misrepresentation? What does it take for something to rise to the level of bullshit? Does it depend on the truth value of an utterance or speech act? On the intention of the speaker? On the inferences a speaker makes about an audience's state of mind? And, normatively, is bullshit more reprehensible than lying? More innocent? More insidious? Does it belong to an entirely different ethical classification?
Fortunately, philosopher Harry Frankfurt wrote the (very short) book on Bullshit a few years ago, trying not only to provide a conceptual analysis of what bullshit is exactly, but to also say something about the ethics surrounding bullshit. Here's a little preview of why it matters:
"The essence of bullshit is not that it is false but that it is phony."