Here’s a cool little miracle that happens all the time and we barely even think about it: A song isn’t truly finished until the listener completes it in their mind. I’m not talking about the noise of trees falling in an empty forest. I’m talking about the fact that all music is a collaboration between a sender and a receiver — the same way that literature is a collaboration between a writer and a reader. Art isn’t a thing, it isn’t stuff. It’s an experience. And it takes two.

Maybe that explains why Solange’s new album, “When I Get Home,” feels so generous in its half-presence. Here are umpteen different lullabies, each drifting through time with a slipperiness that makes them feel unfinished compared with master strokes by Solange’s forebears, say, Janet Jackson or Prince or Lauryn Hill. We’ve heard Rihanna working in a similar mode on “Anti.” Ditto for Frank Ocean on his matching 2016 albums “Blonde” and “Endless.” These are recordings that invert the generosity of the R&B that influenced them — instead of ramping up yesteryear’s maximalism, these songs make room. And in Solange’s case, the word “home” is right there in the title. There’s enough space in this music for us to live inside it.

The whole thing starts with a positive visualization: “I saw things I imagined.” Solange sings a version of that lyric 16 different ways, and by the time she finishes her final lap around the track, we’re hopefully seeing some things, too. The committed vocal repetition throughout “When I Get Home” feels both casual and intense, and it makes time move in strange ways. Solange’s refrains can make succinct snippets of music feel mysteriously drawn out, while her most dynamic note-bursts almost always seem to evaporate too soon.

Occasionally, she bends space and time altogether. On “Beltway,” she sings about a desirous love-loop meant to evoke the highway that encircles her native Houston, but as the melody yearns, the song begins to move as if it’s climbing an ascending spiral.

On “Dreams,” there’s a delicate push and pull between dazed distance and wakefulness, hope and disappointment. Solange’s mantra line — “Dreams, they come a long way, not today” — is the prettiest thing she sings on this album, but before we can float off into perfumed oblivion, another voice appears in the background, chanting from across a hypnagogic chasm: “Sometimes, I feel I’m going down/ Sometimes, I feel I’m gonna die.”

That voice belongs to Devin the Dude, the great Texas rapper who does pathos and weed jokes with expert equanimity. And he’s just one in an astonishing array of guests on “When I Get Home,” a list that includes Scarface, Cassie, Earl Sweatshirt, Sampha, Steve Lacy, Gucci Mane, Playboi Carti, Devonte Hynes, Pharrell, Panda Bear, Metro Boomin and more.

Their cameos are far from splashy. Instead, these maestros appear like stealth thought bubbles or fuzzed-out memories. And when they do, it’s easy to feel like we’ve reached a deep vantage inside Solange’s head space. We’re her collaborators, too. We hear things she imagined.