This is the second post in a yearlong series. Read about it here and see the list of all songs in the series here. A new post about a different song will be posted each Monday throughout 2016. You can listen to the songs in a Spotify playlist.

When The Doobie Brothers recorded “Livin’ on the Fault Line,” producer Ted Templeman overheard singer and keyboardist Michael McDonald casually playing a riff. Templeman implored McDonald several times to finish that song, as Templeman felt it could become a hit. McDonald put it off until a few years later, when Kenny Loggins came to his house for a songwriting session and heard McDonald playing that same riff on the piano. They wrote a bridge for the song that day, and the next day, they wrote the chorus for the song that ultimately would become “What A Fool Believes.”

The song was recorded for The Doobie Brothers’ “Minute By Minute” album, which came out in December 1978. It became the band’s biggest hit and defining song. It reached number one on the Billboard Hot 100 for one week in 1979, and the song was awarded Song of the Year and Record of the Year at the Grammy Awards in 1980.

But five months before The Doobie Brothers’ version was released, Loggins released his version on his album “Nightwatch,” in July 1978.

I have struggled on which version to consider the original, and which version is the cover, if either version is to be considered a cover at all. Normally, it seems straightforward that the first recording is the original and any version that follows that is covering the original. But I’m not sure that applies in a case when two people co-wrote a song and then each co-writer concurrently released his own version. Though Loggins released his version first, The Doobie Brothers’ version featured McDonald singing a song that he co-wrote. If it’s a cover, then it’s a cover by technicality only, deserving of a footnote.

We tend to think of covers as songs in which the cover artist takes a familiar tune and puts a new spin on it. But that’s certainly not the case here, as the song exists, in no small part, because of McDonald.

This song’s history has caused me no shortage of hypothetical questions. If two artists released their versions of a song on the exact same day, we couldn’t use release dates as a way of gauging which was the cover and which was the original. We’d have to look at which one was recorded first, because it’s conceivable that one artist could hear another’s unreleased track and cover it. That’s not the case with “What a Fool Believes,” but it’s certainly possible that listening to one recording could influence the other artist’s version of the song. Does who recorded it first matter more than who released it first? What if, hypothetically, they not only released the songs on the same day, but recorded them on the exact same days? Whose version would be the original, and whose version would be the cover?

Loggins might have co-written the song and released the first recording of “What A Fool Believes,” but in collective pop culture consciousness, that is a Doobie Brothers song. To many, McDonald is a standard-bearer of what was once referred to as “blue-eyed soul,” and his soothing voice pairs nicely with the pleasant synthesizers that back him on “What A Fool Believes.” Not surprisingly, Loggins’ version sounds similar to The Doobie Brothers’ version. Loggins’ take has more texture and layering to it, though, as the guitar sounds more prominent in his version than in the keyboard-heavy version by The Doobie Brothers.

Loggins’ album “Outside: From the Redwoods” features a live duet with McDonald. It’s slower and softer than either of their previously recorded versions. They sound as if they’re not trying to wake the neighbors. And then the sax comes in and he doesn’t care about waking anyone.

In 1980, Aretha Franklin covered “What A Fool Believes” for her album, “Aretha.” Her vocals on the track make McDonald’s and Loggins’ versions sound cold, quiet, and almost bored. To call her take lively is an understatement, as she sounds like she’s singing a Gospel song at a revival in a packed church, all over handclaps and danceable Pointer Sisters synthesizers. Franklin’s version is an exuberantly warm, almost-but-not-quite-too-enthusiastic hug, making Loggins’ and The Doobie Brothers’ version a cold fish handshake.

English dance group M People released a version of “What A Fool Believes” on its greatest hits album, “The Best Of M People.” The track has minute of buildup before singer Heather Small starts singing the familiar lyrics. Electronic music — particularly disco and house tracks — can sometimes sound void of humanity, but M People’s pairing Small’s deep, soulful voice with Paul Heard’s and Mike Pickering’s emotional keyboards led to dance music that sounded as visceral or relatable as any Motown song.

My favorite version is from Self. More than a decade before Jimmy Fallon and The Roots made it their schtick to bring in artists to re-record a song by that artist using nothing but classroom instruments, Self released an album of songs recorded on toy instruments. Though that premise sounded like a gimmick that could get old very quick, “Gizmodgery” might be Self’s most listenable album and has held up since its release in 2000.

My friend Keith introduced me to it when we were freshmen in college. We had just moved into the dorms, where we had access to Napster and could play all our favorite songs for each other. As has been the case whenever I’ve met a fellow music nerd, we tried to stump each other with bands and songs that we hoped the other had never heard. Such was the case when Keith said, “Wanna hear a version of the Doobie Brothers that sounds like it was recorded on Fisher Price toys? Because it was, and it’s awesome.”

Enough time has passed that I can finally admit that this quirky cover version was my introduction to the song. I can’t say I have any memory of The Doobie Brothers from before college, though I had enough awareness to know who they were. And because I had just met Keith and didn’t want him to think I was a total noob, I kept my lack of Doobie Brothers knowledge to myself. (Sorry, Keith!) I just listened to the song, which Keith promised would be awesome. And it was awesome.

Since then, of course, I have gone back and listened to The Doobie Brothers’ version, but it sounds too earnest and serious now I’ve gotten to hear it on toy instruments that were made to be played by drooling children who may or may not be potty-trained. The Doobie Brothers’ version a perfectly fine song, but I can’t help thinking of that version as a demo, a first draft that needed reworking before becoming the Self version.

Much in the same way that Trent Reznor is the mastermind of Nine Inch Nails, Matt Mahaffey is the brains behind Self. When listening to Mahaffey’s version, one can tell he had fun making it. He should have had fun, because it is him playing with toys. And it’s a version that endures for multiple listenings. Playing a song on instruments meant for children could quickly become a tired joke, but the buoyant melody of the original song translates well to toy instruments without sounding jarring or like a gimmick. Mahaffey is a skilled musician, and that comes across on this track, despite the obvious limits of the equipment he’s chosen to use. I have enjoyed many of the Self albums, but I think this album was the best way to discover Mahaffey and his whiney-but-endearing voice. From that moment on, I’ve learned to always trust anything that comes out of Keith’s mouth that starts with “Wanna hear…”

I do not deny that Keith is a big reason as to why I like this Self version, even if I do think I would love it had I discovered it independently of him. But I think that’s how many of us approach songs, particularly cover songs. Our affection for the feelings and memories triggered by the songs we love play into how we judge any other version of the song, even if that “other version” of the song is the original version. Or original version(s), as the case is for “What A Fool Believes.”

You can listen to these songs and previously discussed cover songs in a Spotify playlist. Read about the rest of the series here.