when i read robert fludd, well i dont really remember if it was robert fludd, but it was a very antique /x/ related book, the beginning of the book is pretty much the author being thankful for the king (or princess? i dont remember) for requesting him to write what he was writing, and ive seen this on other books too and it's kinda mind boggling. regarding your OP, i believe the earth is 6000 years old. considering what i just said about the intellectual of the time and the "royalty" of the country he was being thankful for (and also for not being imprisoned, which i didn't mention, since that type of knowledge was forbidden) we can begin to consider that most people in the past were pretty much illiterate npcs/hylics, and that there huge imposed limitations on the people who were not hylics. this still apply nowadays btw, people are the same as ever despite the hand held "education" that were made virtually accessible to the people. even with social media most people will either do oneliners about the mundane (food, clothes, other people, most of the times celebrities) or at best repeat what the upper class tells them to repeat (that being propaganda to change status quo of something, such as ideologies/politics matters) and the pneumatic "intellectuals" of our time get censored or outright persecuted in the shadows all the time, and that's why we are on 4chan, lol.