As I walked back from precept on Wednesday something about the sickening humidity reminded me of a song my sister and I shared last July. And though I knew the two-day heat-wave to be cruel and short-lived, still I was lulled into summertime nostalgia by the eighty-degree April breeze.

* * *

I drive a little too fast and my sister sits beside me in the passenger seat, both of us pretending to enjoy the screaming of our ugly New England highway—all four windows down is as close as we’ll ever get to a “drop-top” in a Volvo station wagon with broken AC.

To the doubtless annoyance of every passing driver, our car vibrates to the beat of blaring pop radio. A weepy Bruno Mars song ends, and the first few piano notes of a lullaby play over a quick beat. The unmistakable voice of Eminem tells us, “I know sometimes/ things may not,/ always make sense to you right now.”

“Yes!” my sister screams, turning up the volume all the way. Mockingbird. “This was my jam in 7th grade!” I say, but my voice is absorbed by the roar of the road and Eminem’s distinctive tenor.

I see my sister next to me rapping along with him, so I join them. We know all the words, and sing the chorus shamelessly, “Hush little baby don’t you cry, everything’s gonna be all right/ Stiffen that upper lip up little lady, I told ya, daddy’s here to hold ya through the night.” In “Mockingbird,” Eminem apologizes to his daughter. He tells her he’s sorry for the pain he’s caused her, the Christmas presents he couldn’t buy her, her mother’s drug addiction. The lyrics are not exactly cheerful, but the soft, continual presence of a lullaby keeps the song from being too tragic for a summer day. It’s a riveting sadness that leads my sister to exclaim, “That’s the best song ever,” when it’s over.

* * *

If you haven’t heard the song “Mockingbird,” you should probably stop reading this and go listen to it. The song’s genius is not simply in the lyrics, but in the fact that its lyrics are built upon the only lullaby everybody knows—“Hush, Little Baby” is the catchy mechanism by which “Mockingbird” captured the undivided attention of millions in 2005.

The technical word to describe Eminem’s use of the lullaby in “Mockingbird” is “sampling”—when artists and their producers borrow a portion of a preexisting song for their own – and it’s hardly a novel technique, especially in hip-hop and rap. In fact, it’s virtually impossible to name a rapper who doesn’t sample. Some samples are especially obvious. In “Shine,” Lil’ Wayne takes the infamous chorus to Al Green’s “Let’s Stay Together,” and adjusts it to reflect witty arrogance rather than devotion— changing “I’m so in love with you” to “I’m way more fly than you.” But many samples go unnoticed by the majority of listeners. In “Thrift Shop,” (over it?) by Macklemore & Ryan Lewis, the underlying saxophone riffs were borrowed from 1960s R&B.

It’s easy to see why rap songs are rarely completely original. The spoken nature of rap means that lyrics and accompanying vocals or instrumentals are not musically codependent in the same way sung lyrics and their accompaniments are. It’s true that rap and the music behind it must fit together rhythmically, but the lack of melody in the lyrics frees rap songs from the constraints which define other musical genres. And while rappers generally create their own raps, they are often not responsible for the music portion of the process, which converts poetry into song. This job falls to a team of producers and musicians, and sampling is integral to their process. Sampling is musical recycling; the ability of artists to reuse portions of old songs rather than having to start from scratch has made rap the phenomenon it is today.

Yet while the continued growth of rap has resulted in large part from sampling and the existence of catchy melody behind the artist’s lyrics, in recent years, pop songs have begun to sprinkle rap into their songs, perhaps in some desperate attempt to cater to a wider audience. The trouble with this technique is that quality of rap is so often compromised when its used in place of a melodic bridge. Take, for example, the song “Payphone,” the 2012 hit single by Maroon 5. Two versions of the song were released, one with a “rap edit” by Wiz Khalifa and one without. Both versions are dominated by vocals; lead singer of Maroon 5 Adam Levine tells listeners “I’m at a payphone/ trying to call home/ all of my change I’ve spent on you.” In the rap edit, Wiz Khalifa boasts about how the money he’s made and the cars he bought with it. The “Rags to Riches” story is a recurring theme in rap lyrics, and hardly something to scoff at when it’s done well, as it reflects the lives of many artists. But Khalifa’s words reflect the negative stereotype that people who dislike rap so often associate with the genre: the widely held notion that rap is little more than a method of bragging about material wealth through crass rhymes and shallow lyrics. The rap interlude begins with, “Man, fuck that shit/ I’ll be out spending all this money/ While you’re sitting round wondering/ Why it wasn’t you who came up from nothing/ Made it from the bottom/ Now when you see me I’m stunning/ And all of my cars start with a push of a button.” It doesn’t any get better.

The lack of power and wit in Khalifa’s lyrics reflect a trend in pop music, which is increasingly using mediocre rap to distract from a general lack of substance. It’s a shame, because rap and pop can undoubtedly be successfully combined. But failed rap verses in pop music will only solidify rap’s lack of worth in the minds of people who already see it as such. Changing people’s minds about such a stigmatized musical genre means making both portions of the Rap+Pop combination of high quality. Otherwise, we risk irrevocably stunting the growth of a musical genere, and people who don’t actively seek out rap will never come to recognize that rap is far more than a spoken alternative to song.