JF Ptak Science Books LLC Post 1922
Much of human intellectual history has been dedicated to looking inside, seeing the unseen, the stuff underneath, the invisible, the clouded, the inscrutable, the things-behind-something-else. If you could somehow weigh all of the stuff that we know that is “visible” versus all of the other stuff that is not, I think that the scales would fly over instantly into the world of the unseen. Some of this material though does not have a measure: for example, numbers are part of the unseen world, ideas made of nothing, points and lines in an imaginary series of planes and dimensions, and so have no mass themselves. Everything that is alive on and in our bodies, on our skin, in our water and food, and which were all basically unknown until the invention if the microscope, have little weight in and of themselves, but when you add the whole biota together…well, then you’ve got a whole weighty lot of nothing Then there’s the stars unseen beyond the six or eight thousand that we can see without a telescope, the rest of the universe waiting, discovered only 400-odd years ago, a very weight affair (and that's not counting the dark matter). I know that this is sort of a horrible argument, a beery and inelegant way to describe the path of human knowledge, but it strikes a (dis)chord with me.
What is the history of the unknown, anyway? Its seems like an infinite volume in Borges' infinite library. After all, at any given point in time it would not be possible to know what the things unknown in your universe were, though you could guess at the absence of things by the changes they brought to the known stuff around you. And to go back and write a history of the unknown would probably show an expansion of the topic rather than its collapse. However, if we are dealing in a Borgesian vocabulary we could establish that The Unknown at some point in the future becomes finite, and that a human-techno-cyborg race was closing in on the concept of the unknowable unknown having somehow established its parameters, and that at some point in the prickly future, the end of the unknown was in sight. As a matter of fact, it could be stipulated that the concept of the Unknown would cease to be in existence on 26 March 3012. Then it would become time for a special assortment of people to work together to create the unknown, even as galactic brain churned in the background producing all of the possible works of literature/art/music, filling up the gap between the known and the unknown.
Creating unknowables in a time of the Post-Unknown would be, um, problematic.