An “invention” is, of course, not just a product you make, it’s a story you tell, a fancy you fashion. This linguistic slipperiness runs through Alex Gibney’s The Inventor: Out for Blood in Silicon Valley, his gripping critique of StartUpLand, a place pathologically allergic to plain speaking. Gibney’s Enron: The Smartest Guys in the Room (2005) is one of the definitive portraits of corporate American group-think, flagging up the delusional market faith that would help decimate economies a couple of years later. The dangerous sway of belief and magical thinking are recurring preoccupations of the film-maker— his previous film was…