What is a word for something that can be said to be "unproven", but because the context in which any such proof would appear does not yet exist? I can think of contested, but are there any others?
I hate to disregard an explicit request for a single word, but I really think you'd be missing a good opportunity to illustrate an important concept if you didn't use:
Black Swan - After Dutch explorer Willem de Vlamingh discovered black swans in Western Australia in 1697, the term metamorphosed to connote that a perceived impossibility might later be disproven.
from Black Swan Theory; Wikipedia
This is no small concept and is "widely" understood:
Since being published in 2007, as of February 2011 has sold close to 3 million copies. It spent 36 weeks on the New York Times Bestseller list list; 17 as hardcover and 19 weeks as paperback. It was published in 32 languages...
The Nobel Prize winning psychologist Daniel Kahneman wrote “The Black Swan changed my view of how the world works” and explains the influence in his 2011 book Thinking, Fast and Slow.
from Black Swan (2007 book); Wikipedia