My f avourite moment in the Coen brothers' comedy The Big Lebowski comes when Jesus Quintana walks up to the Dude in the bowling alley and says: "Liam and me, we're gonna fuck you up." (He's talking about a bowling match.) "Yeah?" the Dude replies. "Well, that's just, like, your opinion, man." The exchange nicely captures the confusion that increasingly surrounds the distinction between "hard" and "soft" knowledge, or things which are and aren't provable. Attempting to take the sting out of Jesus's statement, the Dude ignores the fact that he is making a prediction, and instead claims that he is doing no more than expressing an opinion—which is something that cannot be proved either way. But a prediction may be proved, of course—not immediately, but when the event about which the prediction is being made takes place. The logical conclusion of the Dude's position is that the outcome of a sporting contest will always be merely a matter of opinion—which is clearly ridiculous, and hence funny.

In the above exchange, the Dude is mistakenly attributing "soft" properties to something—a prediction—that will soon belong to the category of "hard" knowledge. But the slippage can also occur in the opposite direction. A common example is the word "refute," which is increasingly used simply to mean "reject" or "disagree." Here, people are doing the reverse of what the Dude does: they are trying to attach hard, or absolute, qualities to what is really just an opinion. To refute something is not simply to disagree with it, but to show it to be false: there is a burden of proof. A further layer of irony (not to mention an unwitting tautology) is added when people use the formulation: "I absolutely refute that statement."
William Skidelsky