The inverse rule
So, you recently arrived from Alpha Centauri and need a guide to understand how people express what they know? The first thing you have to learn is Newton's unheralded fifth law of thermodynamics, The Inverse Rule. Here are four variations on it:
Whatever people say they're not, they are. "I am not a crook," said Nixon. Of course he was. "I did not have sex with that woman." Sure he did. "Nicole and I were talking about getting back together." Yeah, but the discussions hit a snag when he chopped her head off.
Whatever people say they value, they don't. "Hey, hey," interrupts your a-hole manager, "Don't say 'I.' Say 'we.' It's all about the team." This is your clearest sign that he's a raging egomaniac who will sacrifice all those around him to get an office six inches wider than the one next door. Or, the political candidate who says he's the Decency Guy is about to give a speech about restoring civility and dignity to the office when he's heard referring to a reporter as an "asshole"--obviously meaning it in only the most civil and dignified manner.
When humans use words that signify certainty, they are uncertain. For example, "Certainly, the West Coast can be counted on to make its numbers" literally means "I'm not certain that the West Coast is going to make its numbers, but I sure hope so."
Humans like to generalization. All generalizations are false if applied to every individual, risky if applied to any particular individual, but are often true if taken at a sufficient level of generality. (This is, of course, itself a generalization.) For example, "Jews are Democrats" is false if taken--stupidly--to mean that every Jew is a Democrat, may not be true if applied to any particular Jew, but is true if taken as the generalization it clearly is.
Now on to a truly advanced topic: What a human male means when he tells you that he loves you...
David Weinberger is editor of Journal of the Hyperlinked Organization.