In 2016 Michael Winkler wrote an award-winning essay that mentions his “schisms” of self and experiences with depression, the pain of which “intermittently seemed unendurable”. Five years later, his surreal, “exploded non-fiction novel” Grimmish – the first self-published work shortlisted for the Miles Franklin prize – told the story of the “pain-eating” boxer Joe Grim. Now, in Griefdogg, another wry, existentially probing novel, Winkler is again plumbing psyches – his own, yours and mine.

Griefdogg begins with an unnamed narrator, an implied surrogate for Winkler, struggling to draft a speech for a funeral. The deceased, we learn, is Jeffrey Watson-Johnson, a middle-aged, climate-conscious, fitness-obsessed hydrologist (a studier of water flow) living in Mildura. He fancies himself a Don Juan, though he and his wife, Martine, haven’t had sex in three years and seven months. He’s a vegan, community-minded and a “straight arrow”. He’s disciplined and monotonous, an uninspiring yet effective presence on the tennis court. He restacks the dishwasher the way he likes it.

But after he and his cousin fall backwards into a life-altering inheritance, and then into a hotel bed together, a dormant malaise awakes. Exhaustion hits Jeffrey: his work is futile, no one cares, the climate battle having long been lost to “crony capitalism and toasty-warm apathy”; his conscientious life and all these ceaseless decisions are for naught. To Jeffrey, everything seems to pale before the “mystery and majesty” of the colossal realms of water beneath the earth’s surface. Eventually, something snaps – opt me out of everything, he implores his family and friends: “I want to be a human, but live as a pet.”

Thus, the transmogrification begins. Jeffrey becomes Hubert, a family dog aspiring to a Zen-like state, dozing in the sun and watching birds along the Murray while the responsibility for his care is foisted on his loved ones. His life, dutifully, falls apart. But from this newfound detachment, a new sense emerges: an ability to tune into and help relieve other people’s “secret grief”. Questions arise. How does one escape “the pain of being upright, not relaxing in a grave”? What privileged indulgence permits the leisure of disillusionment? Do life’s relentless obligations conceal the anguish that pools in each of us? Would we treat the natural world differently if it had “memory and feelings”?

If it all sounds a bit cryptic, it is.

While tracing the contours of these personal and terrestrial scales of grief, Winkler draws attention to the artifices of his own premise, exposing the seams. “We are, of course, in the business of excavating and parlaying metaphors,” his proxy narrator reflects at one point, seemingly mocking his own attempt to articulate the ineffable. We witness this narrator struggling to write, identifying with Jeffrey (his creation) and his desire to annul the contract of adulthood. These autofictional flourishes remind us of the novel as artificial construct – “But I lie. (You know I lie!)” – and leave us with yet another question: beneath it all, what is of any meaning?

A foil to all this cerebral legerdemain, though, is Winkler’s levity. Griefdogg is funny, despite and not because of the innumerable, gutturally groan-inducing dad jokes that begin to afflict Jeffrey like a psychosis. For a novel replete with ontological asides, literary digressions and detailed hydrological elucidations, you blow through it, much like the leaf in the wind that Jeffrey aspires to become. Winkler is skilled at scratching a metaphysical itch you didn’t realise you had, nudging you down pleasurably tortuous, sparky neural pathways. He is somewhat less successful, though, in making you feel much about it, and the novel’s disparate parts don’t always sit in harmony. There pervades too – ironically, perhaps intentionally – a sense of detachment.

Regardless, Griefdogg is ambitious, a compelling novel told with an already recognisable Winklerian voice: erudite, uncanny, bleakly comic, daggy. It is part beguiling ode to “ordinary citizens concealing ordinary secrets”, part sardonic mockery of navel-gazers, part inquisition of masculinity and midlife inertia. It is also philosophically and climatically poignant; Winkler’s attempt to spelunk into the recesses of himself and “wring words from underground water flow” – a grasping-at of something personal, primordial. He leads you to the water and you drink.

• Griefdogg by Michael Winkler is out now (Text Publishing, $34.99)