Fungi

Fungi occupy a role far larger than their familiar forms suggest: they recycle organic matter, build soil, connect forest life, and produce compounds that can alter animal consciousness. The book moves between the laboratory study of psilocybin and the ecological work of Paul Stamets to recover fungi as active participants in nature, not merely resources or objects of human study. Their networks invite an expansive account of life’s interdependence, while the scientific status of claims about fungal intelligence remains a question to examine rather than assume.

A kingdom obscured from view

Fungi are described as one of the least understood and least appreciated kingdoms of life. Their ecological work is foundational: by breaking down organic matter, they return materials to living systems and help build soil. Without that decomposition, dead plants and animals would accumulate rather than re-enter the cycles on which other life depends. Yet fungi also face deep human suspicion, in part because some are poisonous. Stamets argues that this aversion is striking given that humans are genetically closer to fungi than to plants, and that both humans and fungi depend on energy first captured by plants.

Psilocybin mushrooms make that neglect especially consequential. Their psychoactive compound comes from a fungus, but the laboratory setting can make that origin easy to forget. In contemporary research, volunteers receive synthetic psilocybin as a small pill, not mushrooms; the clinical environment further separates the experience from the organism in which the compound occurs. The book points out that the mushroom’s presence is largely reduced to a ceramic decoration in a session room, even as volunteers report profound changes associated with its chemical. The resulting distance obscures a striking natural fact: a fungus produces a molecule capable of temporarily changing mammalian consciousness.

The history of that relationship extends beyond the laboratory. Psilocybin mushrooms became known to science in the 1950s, while Mazatec people had used them secretly for healing and divination since before the Spanish conquest. The active compound was identified, synthesized, and named in the late 1950s by Albert Hofmann. LSD, too, has a fungal origin: it was derived from ergot, a fungus. These examples connect modern pharmacology to organisms and practices that clinical accounts can leave in the background.

Networks beneath the forest

Stamets has made fungi’s practical value a public cause, presenting mushrooms as potential contributors to solving environmental problems. His concept of Mycoremediation draws on fungi’s capacity to break down complex organic molecules. After the Exxon Valdez oil spill, he demonstrated the approach with oil-contaminated waste: in a comparison shown in his presentation, a black, oily heap inoculated with oyster mushroom spores was, four weeks later, reduced by about a third and covered with mushrooms. The example gives his broad advocacy a material demonstration: fungal processes can act on pollution, not only sustain less visible ecological cycles.

His more far-reaching account centers on mycelia, the networks of fine filaments through which fungi extend underground. In Mycelium Running, the title refers both to mycelia spreading through the ground and to Stamets’s view that they help organize living systems. He describes these networks as Earth’s natural Internet: branched, redundant, self-repairing connections that can extend over great distances. One honey fungus in Oregon, cited in the book as the largest organism on earth, spans 2.4 miles.

The book distinguishes the suggestive metaphor from evidence that gives it substance. Slime molds have demonstrated an ability to navigate mazes toward food, sensing its location and growing in that direction. In forests, mycelia link tree roots, supply nutrients, and convey information about environmental threats; trees can also send nutrients selectively to other trees. Taken together, these findings make a forest appear less like a collection of isolated plants and more like a connected community, with fungi organizing some of its exchanges. They support a picture of fungal networks as responsive and consequential, though they do not by themselves establish every claim made for fungal consciousness.

Fungi, animals, and altered minds

The question of fungal agency becomes more provocative when fungi affect animals directly. Cordyceps offers an unsettling example: it can take over an ant’s behavior and eventually produce a mushroom from its head, spreading fungal genes. The image prompts a comparison with Stamets, whose life and work are devoted to fungi. The analogy is pointed but not literal: where the fungus commandeers the ant, Stamets has given himself to advocating for fungi, spreading their spores and their potential through research, cultivation, and public teaching.

Psilocybin raises a different puzzle. The book asks why a fungus would produce a substance that so radically alters the minds of animals that eat it. A simple defensive explanation seems incomplete: the compound is produced mainly in the mushroom’s fruiting body, the part most likely to be eaten. Stamets and Terence McKenna have suggested that neurochemistry might be a means by which nature communicates with humans, but the narrator considers this a poetic proposal rather than a scientific account. The question remains open in the evidence presented. Fungal chemistry is demonstrably consequential; its evolutionary purpose is not settled.

This uncertainty matters because fungi do not fit neatly into the familiar division between passive nature and active human observer. Their chemicals can affect animal minds, their networks can alter exchanges among trees, and their decomposition changes the conditions in which other life persists. The book’s account does not require every fungal process to be conscious in a human sense. It instead asks readers to take seriously forms of influence and responsiveness that do not resemble human thought.

A different way of doing science

Stamets’s approach is placed in the tradition of Alexander von Humboldt, who treated human feeling, sensation, and imagination as means of investigating nature rather than contaminants to be eliminated. Like Humboldt, Stamets is presented as a self-taught naturalist and inventor who crosses disciplinary boundaries and uses imagination to notice systems others may overlook. His images of mycelial networks, a forest’s immune system, and nature’s neurological connections can sound romantic; the book notes that research has made some of these images more durable than their initial reception suggested.

The contrast is not between science and fantasy, but between ways of practicing science. A detached observer may treat nature as a set of separate objects, while a relational approach attends to interactions among living beings. Stamets’s claims are strongest where they lead to practical or testable questions: how fungi break down waste, how mycelia connect trees, or why bees visit woodpiles. The book reports research suggesting that honeybees may visit woodpiles to consume antimicrobial compounds produced by mycelia, potentially helping protect their hives. The proposed exchange between bees and fungi remains an invitation to investigate, not a fully answered transaction.

Fungi thus hold together the book’s scientific and philosophical concerns. They are organisms with material effects, sources of compounds that have altered human and animal consciousness, and participants in networks whose full workings are still being discovered. To take them seriously is to loosen the assumption that nature consists of inert objects awaiting human use. Stamets’s expansive language sometimes outruns what can be firmly established, but the evidence described gives his central insistence weight: life underground is connected, consequential, and less passive than a human-centered view has allowed.