Dark Energy, Newton's Law and the LHC: Vacuum Energy: the Dog that Didn’t Bark

This note briefly summarizes two things. First, it states why I believe progress understand- ing Dark Energy hinges crucially on finding a solution to the ‘old’ Cosmological Constant Problem, and more generally reviews why technical naturalness provides such an important clue to solving problems in cosmology. A set of criteria are formulated for judging success when discussing prospective solutions to the problem with their proponents, with a goal to helping properly hold everyone’s feet to the fire. Second, I summarize what I see as the most promising approach (so far), which is possibly the only known technically natural solution yet proposed. Its consistency tests and observational predictions are summarized, as well as a list of outstanding problems.