As usual these experts use word that cannot be used against them.

Paragraph 3 of your post reads:   The article concludes that commodities prices have been pushed too high by speculation, and what might burst the resultant bubble would be a slowdown in the Chinese economy.  The article also quotes Societe Generale analyst (Albert Edwards)  as follows:  "The commodity bubble is nonsense on stilts," he has the "very strong conviction that before the end of this year, commodity prices will be unraveling."  No Societe Generale jokes, please!!

 With the above in mind what happens if the Chinese economy doesn't slow down.  Price stabilize? Rise further?  

Here is my question if this Gene Epstein can say a Chinese slowdown could burst the commodity bubble, is it not fair to say the Chinese growth is driving the price upwards and therefore why is it a bubble?