More on the notion of simplicity

After my earlier post, I read an appreciation of Christopher Hitchens http://www.commentarymagazine.com/2011/12/16/how-hitchens-is-great-even-in-death/ that included this:

"The proper task of the ‘public intellectual’ might be conceived as the responsibility to introduce complexity into the argument: the reminder that things are very infrequently as simple as they can be made to seem. But what I learned in a highly indelible manner from the events and arguments of September 2001 was this: Never, ever ignore the obvious either. "

But of course what is obvious isn't always (or often?) obvious.