Principia wasn't really planned to be put out. It's a nerdy song about the quantum nature of the smallest particles being completely unlike people's intuition. In fact, they're so much closer to being nothing at all than they are to being something, that it's amazing the macro world we walk around in appears to be solid at all. 

Ben was having a nerdy chat with celebrated CERN Physicist

Daniel Whiteson about the existence of gravitons. Getting way above his station, Ben thought he had a proof that gravitons cannot exist. (Ben was wrong..) Daniel is much smarter than Ben.

Alas, after a little more physics chat and sharing this nerdy song, Daniel asked if it could be used on his truly excellent physics podcast, Daniel and Jorge Explain the Universe on their newest episode "What is a particle?"

So here it is, it might end up as a proper release sometime in the future. But for now it's exclusively playable from the website in it's all nerdy glory. Enjoy!