The Age of Entanglement: When Quantum Physics Was Reborn by Louisa Gilder (Vintage Books, 2008) Quantum entanglement is weird. Of all the weird aspects of quantum mechanics, it's the weirdest. The fact that what you do to one particle can affect another particle with no physical interaction between them--"spooky action at a distance," in Einstein's words--is a fact of nature, but just because something is proven by every experiment we throw at it doesn't mean we have any idea why.
In the summer of 1269, the southern Italian city of Lucera was under siege, and in the army outside the city walls a man was writing a letter. Decades earlier, in the first half of the thirteenth century, the Holy Roman Emperor Frederick II had expelled approximately 20,000 Muslim inhabitants from Sicily in an attempt to quell religious unrest on the island. The uprooted Muslim communities resettled in southern mainland Italy, and many of them ended up in Lucera. After the forced resettlement, Frederick II made what he probably believed was a very fair deal with his displaced subjects: they were permitted to practice their religion in exchange for taxes, military service, and support against the his enemies.
One of my favorite games to play while studying the history of science is to match the ideas and rhetoric of openly anti-science modern public figures to the era of history in which they and their ideas would feel most at home. I think if we really set our minds to it, and we invent time travel, we can find a place in history for even the most temporally-displaced persons. That way, when we find ourselves thinking, "Why, his ideas are positively medieval, does he even know what year it is?" we need not concern ourselves with the lengthy and painful process of bringing a medieval thinker into the modern era. We only need to identify which century would be a more suitable home, and send him there.