Macfarlane's books are organized around questions. Not chapter-organizing questions; book-organizing questions. Why do we climb mountains? (Mountains of the Mind, his first book.) Is a river alive? (his recent four-year book.) Can a forest think? Are we being good ancestors? (a question Macfarlane attributes to Jonas Salk.) Does a mountain remember?1
The questions look simple. Why climb mountains? George Mallory's famous answer (because it's there) was wisecrack in 1922 and has been the legendary answer ever since. Macfarlane found it useless: it took me 300 pages to answer the question in Mountains of the Mind. It took me 300 in Is a River Alive. And I didn't come to the end of any of them.1
Perell helps him crystallize what the questions are doing: they are portals. Macfarlane: They're modest. They're the wardrobe. They're the modest entrance point. And then you push through the through the fur coats. Whoosh, you're into it.1
The reference is to Narnia. The wardrobe is small, conventional, easily-overlooked. Push through the coats and you find yourself in a vast snow-covered landscape with a lamppost. The portal-question works the same way: the question looks innocent — is a river alive? — and once you commit to taking it seriously, you find yourself in territory it would take three hundred pages to begin to navigate.
Three properties recur across Macfarlane's portal-questions:
Property 1 — Deceptive simplicity. Is a river alive? sounds like a yes/no question a child could answer. The simplicity is the wardrobe-camouflage. The actual answer requires hundreds of pages of cross-disciplinary work, and even then is not closed.
Property 2 — Stakes the writer (and reader) cannot dismiss. A portal question matters. Climbing mountains is a real thing humans do at risk of death; whether they should is a real question. Whether a river is alive bears on environmental policy, indigenous rights, ecological consciousness, and the metaphysics of agency. The question's mattering is what holds the writer to it for years.
Property 3 — Resists closure. A portal question does not have a yes/no answer that, once given, settles the matter. It opens into more questions, more frames, more relevant considerations. The book's value is not the answer; the value is the territory the question opens.
The portal question is the book's engine for the years of work the book requires. Macfarlane's books take 4-8 years. The writer needs something that holds focus across that span. A theme isn't enough — themes can drift. A topic isn't enough — topics are too inert. A portal question is enough because the writer has not yet answered it and is being pulled along by the gradient of answering.
Each chapter is an attempt to answer the portal question from a different angle. The cumulative effect across all chapters is the book's response to the question — which is more partial than a definite answer but more substantive than no answer.
Crucial: the writer is not answering the question for the reader. The writer is answering the question for the writer, with the reader watching. The writer's pursuit-of-answer is what generates the prose; the reader follows the pursuit and accumulates their own response to the question alongside.
Macfarlane doesn't pin questions on his desk, but he does pin quotes. For Is a River Alive? he pinned this from Ursula K. Le Guin (which appears right before the first chapter after the prologue):
One way to stop seeing trees or rivers or hills only as natural resource is to class them as fellow beings, kinfolk. I guess I'm trying to subjectify the universe because look where objectifying it has gotten us. To subject is not necessarily to co-opt, colonize, exploit. Rather, it may involve a great reach outward of mind and imagination.1
A great reach outward of mind and imagination. That phrase becomes the structural ambition of the book. The portal question (is a river alive?) plus the structural ambition (a great reach outward) defines what the writing is for over the years.
Macfarlane and Karlsson's animating-question converge on the principle that long-form work needs a question to organize around. Both insist that the question — not the theme, not the topic, not the structure — is the engine. Both require the question to be personal-enough to risk something. The split is scale: Karlsson's animating-question organizes an essay; Macfarlane's portal-question organizes a multi-year book. The architectures are otherwise structurally identical.
Macfarlane diverges from Bilton's theme-as-through-line on the question vs thesis distinction. Bilton's discipline requires you to have the answer (the theme as declarative sentence) before drafting. Macfarlane's discipline requires you to have the question and to not have the answer. The split reveals two genuinely opposed theories of what writing is for: Bilton treats writing as demonstration of a position the writer holds; Macfarlane treats writing as exploration of a question the writer cannot answer alone.
Portal-questions-as-book-engine maps onto two adjacent domains where the same deceptive-simplicity / vast-territory architecture appears: Eastern-spirituality (the koan tradition in Zen Buddhism) and creative-practice (the contemporary essayist tradition of the framing-question).
Eastern-Spirituality: Koan as Cognitive Doorway (Zen) — the Zen tradition of koans (what is the sound of one hand clapping; what was your face before your parents were born; does a dog have buddha-nature) deploys deceptively-simple questions that resist conceptual closure and require sustained attention to penetrate. The koan is not solved; it is sat with. Through sustained sitting, the koan opens into territory the conceptual mind cannot reach. Macfarlane's portal-questions are structurally identical: deceptive simplicity, resist closure, require sustained attention, open into territory beyond conceptual answer. The structural identity: both traditions use questions that defeat the answer-format as instruments for sustained engagement with what the answer-format cannot reach. The insight neither domain generates alone: Macfarlane's literary methodology of portal-questions is operating in the same conceptual territory as Zen koan-practice — and the writer who has done koan-work understands viscerally what a portal-question demands. A writer who has sat with what is the sound of one hand clapping for a year understands what is a river alive? requires.
Creative-Practice (Essay Tradition): Tension as Essay Engine — the contemporary essay tradition (Montaigne's que sais-je? — what do I know? — as the founding question) treats the essay as an attempt to circle a question rather than answer it. The tension between the writer's attempts and the question's resistance is the essay's energy. Macfarlane's portal-question scales this essay-tradition principle up to book-length. The structural identity: both forms (essay; portal-question book) treat the question's irreducibility to a settled answer as the source of the writing's productive force. The insight neither domain generates alone: Macfarlane's books are operationally extended essays — the architectural commitment is essayistic (circle the question; refuse closure) even though the format is book. Writers who have internalized the essay-tradition can scale to portal-question books more naturally than writers trained in argumentation-traditions where books are expected to defend theses.
A third connection worth marking: portal-questions have structural similarity to wonder as survival skill — both refuse the foreclosed answer that the inventory-mind wants to provide.
The Sharpest Implication
If a book's structural sustainability across years requires a question the writer cannot answer rather than a thesis the writer can defend, then most book-publishing pipelines (which require pre-sold book proposals with clear arguments) are structurally selecting against the books that produce Macfarlane-quality work. The uncomfortable implication: the writer who can articulate a clear thesis early gets the book deal; the writer who is sitting with a portal-question and doesn't yet know what the answer is, doesn't get the deal until they have done the four-year journey on their own — and most writers can't fund that journey without an advance. Macfarlane's methodology depends on a position (academic tenure plus established literary reputation) that lets him work on portal-questions for years before the book exists. For most working writers, the methodology is structurally inaccessible because the economic infrastructure won't support it. The publishing industry rewards thesis-books and starves portal-question-books — and the cultural cost is that we get more well-argued books with shorter shelf-lives and fewer multi-year explorations that endure.
Generative Questions