An idea extremely prevalent in the current era is that everything is equally valid. For instance you cannot, you will be told, say that one work of art is greater than another because of this equal validity of everything. So a quick look at the logic at play here.
Everything is equally valid. Therefore all statements are equally valid. And an example of one such statement within the totality of equally valid statements is that:
Everything is not equally valid.
And so if everything is not equally valid, then the first statement that everything is equally valid is false. So the statement of all being equally valid contains within itself its own disproof.
This is an extremely important little intellectual matter. It will be argued, once you extend the thinking here from the page to its implications to "real life"- afraid I can't be arsed plotting the intellectual journey- that this is a disproof of democracy itself, or liberalism, but this is a false, defiled version or interpretation of democracy where everything is permitted, and given the falseness of this notion, then the society that permits itself everything will inevitably become falsified, defiled, made decadent and collapse, partly or even significantly effected by those people who will then impose the apparently necessary subsequent harsh order on the collapsing society- most obviously effected by the propagators of the dumbing down of that society's members through the forms of the mass-media.
The Weimar period of something like absolute liberalism, where all, or an idea of all, is permitted, all being equally valid, followed by the inevitable disproof, the totalitarian period, which had exploited the weakness of the misconstrued or false "liberalism" or democracy of the Weimar period. A long earlier piece here.