Think in Bayesian terms. If you update your priors at all when the lie comes, then the firehose will overwhelm you, because the lie (or a similar, related lie) comes so often. If you update at all, then you wind up believing it.

But the only defense is to not update your priors. That means that you don't update on things that are actually true, either.

This is basically the death of epistemology. How do you know, and how do you know you know? It's no longer possible in this environment.

Postmodernism talked about a post-truth world. Putin has made it a reality.