Eli Pariser has been thinking a lot about this idea of the marketplace of ideas. In civics class we learned that this is the way that the truth kind of comes to the top, that the best ideas displace the worst ideas. But I think it’s a better metaphor than it intends to be, in the sense that marketplaces, as any economist will tell you, are not necessarily the place where the best product comes to the top. There are all sorts of dynamics that determine who wins and, in fact, if you follow disruption theory, which is in vogue in Silicon Valley, it’s all about how actually a worse product can beat a better product in the marketplace. We have a marketplace of ideas in the bad sense of that term, not the good sense of that term, where what wins in the marketplace may not be fair, it may not be right and certainly it may not be true, but it’s based on this very reductive set of rules of supply and demand. We’re all trying to grapple right now with what that means when there are less kind of institutional gatekeepers who are holding in check which ideas are competing with which other ones. But it turns out there are ideas that are very appealing and very contagious that are either completely untrue or that are appealing to our worst instincts about each other.