Lyric discussion by Emjay41 

Cover art for I Know lyrics by Barenaked Ladies

I think this song is a lot less random and meaningless than most of you guys do, imo. I agree with Zamrod that it's social commentary, but I think there's more specific meanings than that.

The first verse seems to be about racism, and the typical teenage superficiality of romance. "I like you because of your image" But I think the speaker is being sarcastic, he is looking at/talking to an attractive, but racist person, and feeling angry and violent, "I have a match; your face, you want to box me?"and he knows that he could argue his non-racist beliefs with this person "My asking you questions you can't answer"

The next part, about the facial hair I think is also about racism. I think the beard symbolizes minorities, possibly specifically Arabs and Mexicans, and I think the mustache symbolizes Hitler, who the speaker finds scarier than these minorities.

The verse about dogs is comparing them to people, and how they are dogs, they are not intelligent as people are, but they don't kill each other over politics and religion and land.

Next verse is about sex and religion, imo. And the last verse, I think is about religion, but also more generally about how everyone percieves things differently, even things that are "facts". And I think that makes the title of the song very ironic, if they are saying that noone really knows anything, they only have a perspective of it, which I believe is true.