A weak defense, insofar as he picked only one point to go all-in on, and it's probably the least significant one. Also, notice his attempt to trivialize "igon value" as "my spelling"; the appropriate phrase would have been "my ignorance". I'd say this rebuttal does more to expose Gladwell as a sleight-of-hand artist than Pinker's actual critique did. It doesn't mean that Gladwell isn't a superbly entertaining writer and storyteller, though; and at his best, a popularizer of damned interesting stuff.