The science of eras in an imperfect one, but it is not an art: It is simply hard to practice, because its defining quality—time—is superior to all others. The beginning of a historical period can rarely be pinpointed until it has passed; the end is often forgotten before it is ever determined.
For example! Political experts have been struggling with a particularly difficult question since at least 2011: When is 2016? Irrelevant old-timers insist that 2016 cannot start until 2015, but nobody has paid much credence to such stubborn contrarianism since 1992, which began in 1989. Eager young hotshots, using a mixture of traditional and theoretical methods, have suggested that [...]