Lovers keep on lovin’. Believers keep on believin’. Sleepers just stop sleepin’. ‘Cause it won’t be too long. What’s THAT supposed to mean?

Aside from the Beatles’ 1965-1969 output, it’s hard to imagine any artist or band having a more productive quadrennial than Stevie Wonder had from 1972 to 1976. No longer a child star but a musician in complete control of his own work, Wonder went into the studio and spun out a succession of groundbreaking songs and albums, redefining R&B with layered keyboards and a social conscience.

The music Wonder created in this stretch was so important that Eddie Murphy made good comedy joking about how difficult it was to joke about him. In his standup, Murphy shared the reaction to his bobble-headed Stevie impression on Saturday Night Live: “Stevie Wonder is a musical GENIUS, man! I got all his albums. I got Music on My Mind, I got Talking Book, I got Fufinity, Fulfillity, fuck it, you know, the GOOD one!”

(For the record, that would be Fulfillingness’ First Finale. Also for the record, Wonder has a pretty good sense of humor himself and has made some memorable SNL appearances.)

And several of the songs from this period featured prominently in an upcoming Popdose discussion of the best protest songs of the rock/pop era. It seemed unfair to pick just a single song, given the steady stream of brilliant commentary that flowed from Wonder’s voice, keyboards and drums.

Two of the albums Murphy mentioned were released in the same year. The second, Talking Book, produced one instant standard (You Are the Sunshine of My Life) and the first of Wonder’s sociopolitical classics, Superstition. Just hearing the hi-hat in Superstition’s intro is enough to tell the listener we’re about to get something more meaningful than most artists over the next several generations were able to produce.

With the follow-up, Innervisions, Wonder showed just how direct he could be in his lyrics. “To find a job is like a haystack needle / ‘cause where he lives, they don’t use colored people,” Wonder sings in the harrowing Living for the City.

But Wonder isn’t someone who loses hope. Even in Living for the City, he brilliantly captures the determination of people living in difficult circumstances: “To walk to school / She’s got to get up early / Her clothes are old / But never are they dirty.”

That brings us to the other classic on Innervisions: the powerful spiritual Higher Ground.

The song is shrouded in mythology because it was released just before Wonder was in a near-fatal traffic accident. Taken literally (“I’m so darn glad he let me try it again / Because my last time on earth I lived a whole world of sin”), Higher Ground is about reincarnation, an interesting topic for someone about to get a second chance at life.

But Wonder isn’t an orthodox anything. Superstition was skeptical of religion — “When you believe in things that you don’t understand, you will suffer” — and Wonder’s spirituality here is, depending on how fundamentalist you are, either too vague or beautifully inclusive.

Like the woman in Living for the City, Wonder is striving here to reach that higher ground no matter what else is happening in the world. Soldiers keep on warrin’, powers keep on lyin’, lovers keep on lovin’ — all part of a world that keeps on turnin’. You can’t stop it, though maybe Wonder anticipated the word “woke” 40-some years in advance with “Sleepers just stop sleepin’.” You have to keep going.

You might think that’s a nice timely message not just for the turbulent Watergate/Vietnam era but also for today’s “post-fact” political chaos. But when is it ever not timely?

Little surprise, then, that this song produced the most memorable cover version from Wonder’s catalog, with all due respect to Stevie Ray Vaughan’s blistering take on Superstition (complete with a one of those witty videos MTV used to air and a cameo from the original Stevie). Flea and John Frusciante turned Wonder’s layers of keyboards into a funky frenzy of percussive guitar chords and a killer slap bass hook, and the Red Hot Chili Peppers had a hit.

But as durable as this song may be — applicable to any decade or any genre — this song is a product of the 70s. The spiritual and social awakening. The striving for something profound. The bedazzling …

So, yes, this is an enduring struggle. Politicians keep on politicking. Haters keep on hating. But we’re going to keep on trying to reach that higher ground.