tla's definition of ignorance is about living in a bubble. It's when you haven't read War and Peace in Russian (and French: let's be frank, the book is at least quarter foreign) and are proud of it, or don't care to read it despite being a self-professed bookie because it's so damn big and you don't want it and you have other things to do instead bla bla bla... It's fine not to read it, I suppose, but if you enter an argument about Russian literature later on (or Tolstoy's literary works, even), you'll be out of your field; if you then presume that you ought to partake in the argument because you're you and because you want it (despite having little to know knowledge on the subject), you're partaking in willful ignorance, shielding yourself from the idea that you can't know everything and/or things that you ought to know about by now. At least, that's how I understand what tla meant. Maybe that's what mk meant, too.