At his blog Lenin's Tomb, Richard Seymour parses the meaning of "post-truth politics," a phrase that has been widely used to describe the era inaugurated by the rise of Donald Trump and like-minded demagogues. Seymour affirms the usefulness of this phrase, but he provocatively argues that truth or falsehood is not rooted in facts alone, but rather in "the register of desire." Here's an excerpt from the piece:
It is not even necessarily the case that there has been a metric increase in the volume of political lying of late. It is simply that there has been a shift in political imaginaries. The ideological context in which we evaluate truth-claims is such that, while fewer people are likely to be taken in by fuzzy satellite imagery of weapons laboratories, proportionately more people are likely to be taken in by the idea that Mexican immigrants are rapists.
In the era of the 'war on terror,' there was much ado about a threat to reason posed by nefarious Islamists, poststructuralists, conspiracy theorists, and assorted leftists. There were various books by 'muscular liberals' extolling an historically disembodied, fetishistic version of the Enlightenment as the unique saleable property of 'Western civilization'. We could easily believe, then, in all sorts of strange and false stories, including about "al-Qaida" -- the blackhole into which all global problems were compressed.
And if the lies we tell, and believe, have changed, it is useless to respond to that with mournful nostalgia for the very recent past. According to Lacan, someone who lies on the couch is always operating in the dimension of truth. One can speak factually all day long, in an empty fashion devoid of (or rather, avoiding of) subjective truth. This is part of the resistance to analysis. As soon as one lies, however, one creates. And there is no creation without desire. Once you start to lie, you tell the truth about your desire -- perhaps in the only way that you can, through displacements and metaphors.
The lies we might tell about immigrants, for example, tell the truth about us. If we are not able to say, "any amount of immigrants is too many, and we should sadistically and brutally punish them for being here," we can instead massively exaggerate the numbers, identify migrants as 'illegals' and 'bogus', and scapegoat them for sexual assault and violent crime.
This is, of course, one reason why it is often useless to approach political argument like a debating society. One can correct false statistics, but people are neither simply deceivers nor deceived. They are, even when lying, operating in the dimension of truth. Correcting a lie, however necessary in its own right, does nothing to get to that other place, the place of desire -- and as such, by itself, it leaves the lie intact.