Who could have imagined, when “The Way it Is” first conquered the airwaves, that Bruce Hornsby would become known not primarily for his supple soft rock, nor his nimble piano work, nor even his easeful way with melody– but rather for his restless, unquietable mind? By Hornsby’s own admission, the success of that song was just a happy accident, no one more surprised by it than he; as Stephen Thomas Erlewine notes, he seemed to abandon pop celebrity the very instant he attained it, and since then he’s flitted from film scores to bluegrass to a stint with the Dead. Wanderlust is his guiding principle, the connective tissue for his body of work, and by this point there’s no justifiable reason to be thrown by his latest flights of fancy; after all, what’s one more rabbit hole from a man so prone to discursion? Take Absolute Zero, a new album that combines the filigree of classical music with the exploratory spirit of jazz, its songs inspired by Hornsby’s fondness for avant composers but also his readings in astrophysics, anthropology, literature, and history. Yes, it sounds like it’s from out of left field; but then, that’s long been Hornsby’s sweet spot.

That’s not to say the album is easily explained. Largely acoustic, Absolute Zero centers on Hornsby’s playing, which moves fluidly from flurried pointillism to plainspoken balladeering, from jostling polytonalities to elegantly rumbling funk. He’s surrounded variously by the thrum of woodwinds, the swell of an orchestra, and the disembodied gurgling of electronics; by the loose-limbed chamber sextet yMusic, long-serving giant of jazz Jack DeJohnette, and whippersnappers like Justin Vernon and Blake Mills, both of whom uphold Hornsby’s restlessness as license for their own unclassifiability. You can call this album many things– brainy, intricate, digressive– but one thing is never is is abstruse. Hornsby may have little interest in pop stardom but he has a keen interest in writing songs that are direct and emotionally available; it’s that instinct, coupled with the complexity of his musical ideas, that make Absolute Zero frictive, surprising, and alluring. On song after song, abstraction is settled into accessibility, complexity resolved into viscerality: Listen to how “Fractals” opens with a clutch of fluttering, syncopated notes from Hornsby’s piano, hovering over the shape of a melody and then suddenly congealing around the entrance of a rigid backbeat; in an instant, the song’s delicacy gives way to ruthless locomotion. You can hear the same kind of streamlined knottiness on “Absolute Zero,” where Hornsby’s piano ponderings are stitched together by the slip ‘n’ slide of DeJohnette’s cymbal work. On “Voyager One,” the band hurtles through the cosmos, woodwinds twinkling like stars in the vista, combustible low end providing the rocket fuel. (“[A] multidimensional hoedown,” Jon Pareles calls it.)

In a canon that’s full of passion projects and labors of love, Absolute Zero is both one of the boldest excursions yet but also one of Hornsby’s cleverest consolidations. Indeed, you could say that this is the nexus to which all his discursions have led. The lessons he’s learned in the movies come to bear in “The Blinding Light of Dreams,” a dizzying high-wire chase scene, tension masterfully sustained by the taut push and pull of the orchestra. And you can hear his affection for familiar structures and forms on “Never in This House,” a domestic diorama that wouldn’t sound out of place on a Costello & Bacharach collaboration. “Ecolocation” is only the clearest evidence here of Hornsby’s fondness for Appalachian vernaculars, a shambling jalopy of a blues number. And “Meds,” a collaboration with Mills and Vernon, illustrates the adaptability of his heartland roots: Listen to how it scales from the unsteady plunking of his piano to the kind of big, arena-swelling chorus his label undoubtedly hoped for in the wake of “The Way it Is” and “Mandolin Rain.” And don’t miss the scrape of the string section, imbuing just the right sense of wobbly unease into the song’s frayed edges.

Hornsby’s intellectual appetite is born out not just in his musical ideas but in his poetic conceits: He draws here from so many systems of inquiry that the album is practically a self-contained liberal arts education. But if he’s engaging with different kinds of analytic thought, he’s doing so as a way into the abstract and the imaginative; he’s less interested in the empirical than in the ineffable, so when he compares a relationship to geometric formations (“Fractals”), it’s not because he’s trying to quantify or explain love so much as to articulate its mystery. His interest in science sometimes spills into the speculative, as in the title song, where cryogenic freezing is posited as the best shot at redemption (“Another chance, it may be better this time,” he hopes). Other songs abide the plurality of complex emotions: “Cast-Off,” full of gauzy synths and spectral murmerings from Vernon, grapples for gratitude in the face of rejection; “White Noise,” based on the writings of David Foster Wallace, considers the deadening effects of chronic boredom. Hornsby is also drawn to historical narratives, both personal and cultural, here employed as frameworks for exploring moral formation and evolution: “Never in This House” chronicles the hobbling effects of a dysfunctional family life and longs to break the cycle, while “The Blinding Light of Dreams” CliffsNotes the history of racism in the American South, name-dropping Jim Crow and Harper Lee along the way. As skeletons rattle in the closet, Hornsby turns his attention to space travel: “Travelling to distant suns may be mankind’s only hope,” he sighs. It’s a thread that connects the song to “Voyager One,” where Hornby exhorts: “Let’s break out of our orbits, free of gravity’s effect/ Let’s leave our little planet, fix relationships we’ve wrecked/ Un-learn all our habits, make sure we all connect.” He’s taking an interstellar view of radical neighborliness, the space program his vessel for increased moral bandwidth and empathy. But he’s also dropping some clues as to what Absolute Zero’s all about: Through these works of imagination, Hornsby’s drawing connections between musical idioms and scholastic disciplines; he’s drawing an ever-widening circle around the orbit of human experience.