Fake news spread online is a clear danger to democratic politics. One aspect of that danger is obvious: it spreads misinformation. But other aspects, less often discussed, is that it also spreads confusion and undermines trust. In this talk, I will argue that it is this last aspect that captures the most pernicious effect of fake news and related propaganda. In particular, I’ll argue that its effectiveness is due in part to a curious blindness on the part of many users of social media: a kind of semantic blindness to the function of their online communicative acts. This blindness makes us not only vulnerable to manipulation to those with a better understanding of the semantic character of online communication, it indirectly undermines the political value of truth—or more exactly, the pursuit of truth, by diminishing confidence in the institutions that protect and encourage that value. In this talk, I will argue that it is this last aspect that captures the most pernicious effect of fake news and related propaganda. In particular, I’ll argue that its effectiveness is due in part to a curious blindness on the part of many users of social media: a kind of semantic blindness to the function of their online communicative acts. This blindness makes us not only vulnerable to manipulation to those with a better understanding of the semantic character of online communication, it indirectly undermines the political value of truth—or more exactly, the pursuit of truth, by diminishing confidence in the institutions that protect and encourage that value.