“Don’t know your past, don’t know your future,” sings Ziggy Marley, son of the legendary reggae singer Bob Marley, on “Tomorrow’s People.” Somewhat obvious, but it sounds great to the thump of a dancehall beat. I’m not one for retrospectives, especially retrospectives of events that just occurred. Those “I Love the 80s” and “I Love the 90s” shows on VH1 drive me crazy. In the greater epoch of human history, it’s been about a tenth of a nanosecond since the events actually occurred. Watching them has all the feeling and nostalgia of opening a time capsule a week after it was put in the ground.