Heh, apparently I have absorbed Sumner's thinking to the extent that I almost wrote his post for him:

When the bitcoin price crash comes, most people will wrongly say; “Aha, I told you that it was a bubble.” But why? Because they will have forgotten about their first bubble prediction. People were calling it a bubble at $2, and again at $30. Now it’s over $200. If it plunged to $35 dollars, the bubble predictors will say they were right all along, but they will have been wrong. They’ve merely remembered their bubble predictions, not where bitcoin was when they made their predictions. [Ha! I wrote this yesterday and delayed posting--that'll teach me. It's $160 tonight]

...I can’t predict where bitcoin is going, but I can predict there will be many false “bubble” claims when it eventually crashes—and it will crash. The only question is whether it will crash from a price so far above the current price, that it’s still a good buy at $160. And the EMH says that the answer to that question is; “God only knows.”

Ah, the nay-saying begins. "Oh no, it's only up 5x over the last month and not 10x!" Remember that the predictions I was talking about blowing were that it would peak in the $30s or $40s; I and and anyone like me was wrong, still are wrong, a fall to 'just' $100 does not make me feel much better about having blown them, and I will still have learned that there are enough people willing to buy into Bitcoin for any reason that its exchange rate can be pushed all the way to $260.

More generally, just as a large price increase does not prove that Bitcoin will ultimately not be a bubble and will go to $100k, a large price decrease does not prove that Bitcoin will ultimately be a bubble and go to $0. We of all people should know to not apply double standards and hindsight bias.