Science

He has been corrected, both patiently and politely and loudly and rudely, over and over again. And he persists in uttering falsehoods.

But he doesn't merely persist in uttering falsehoods. He does so in a manner (what things he insinuates rather than saying outright, what related things he conspicuously doesn't say, what qualifier and caveats he employs) which indicates that he knows he is doing so. He is a fucking liar. He knows it. He knows what he is doing, and it is fucked up.