<span>Johannes Gensfleisch zur Laden zum Gutenberg was a German blacksmith, goldsmith, printer, and publisher who introduced printing to Europe. His introduction of mechanical movable type printing to Europe started the Printing Revolution and is widely regarded as the most important invention of the second millennium, the seminal event which ushered in the modern period of human history; but his the first most famously achieved is the printing press that Johannes Gensfleish zur Laden zum made in the workshop.</span>
Not sure about the 1st one, but it sounds like a cruel irony, or karma, where one does something bad, and later on the same bad thing gets done to you. Breaking the fourth wall is when a character in a comic, book, or tv show/movie talks to the reader, or states that he knows that there is an audience and he is just a character (comes from the old tv sets where there were only 3 walls, and the fourth wall was where the audience would watch in, and cameras would shoot: so when they "broke the fourth wall", they looked out at the audience and talked to them). Externalised conscience is essentially, as far as i know, when a character decides between what he wants to do and what he should do, and there are usually many soliliquies (excuse the spelling) while he makes the decision. Not sure if this is all 100% correct, but that's what my non-drama knowledge allows me, and hope it helps you out a little bit.
Because its hard to depict what they mean because og the culture and because its hard to study it due to its conditions .!.