Animism refers to the worldview that recognizes consciousness, spirit, or soul in natural entities such as rivers, mountains, trees, and animals. Macfarlane presents animism not as a primitive belief system but as a sophisticated understanding of the world that acknowledges the agency and subjectivity of non-human beings. This perspective contrasts sharply with Western rationalism, which tends to view nature as inanimate matter lacking consciousness or intrinsic value. Throughout the book, Macfarlane argues that recovering animistic ways of seeing is essential for developing more respectful and sustainable relationships with rivers and other natural entities.

The Eremocene refers to a proposed geological epoch characterized by mass extinction and ecological isolation, coined by biologist E. O. Wilson from the Greek words meaning “new” and “isolated place.” In Macfarlane’s discussion, this concept represents the potential future age of loneliness in which humans exist as the sole remaining complex life form on Earth due to their own destructive actions. The Eremocene describes not merely the physical absence of other species, but the profound spiritual and psychological isolation that would result from living on a planet stripped of the speech, song, and stories of non-human beings. This term serves as a warning about the ultimate consequence of treating nature solely as a resource rather than recognizing it as a community of living beings deserving of rights and protection.

“Grammar of animacy” is a concept developed by Robin Wall Kimmerer that Macfarlane uses to describe linguistic structures that either recognize or deny the aliveness of natural entities. This grammatical framework determines whether languages treat rivers, trees, and other natural beings as subjects (who) or objects (which/that), fundamentally shaping how speakers perceive and relate to the natural world. Macfarlane argues that English’s tendency to use the word “it” to refer to rivers and other natural features reflects and reinforces a worldview that denies their agency and subjectivity. He advocates for adopting language that recognizes rivers as living beings deserving of respect and consideration, suggesting that changing pronouns from “which” to “who” can help transform human consciousness about natural relationships.

Lifting baseline syndrome is Macfarlane’s proposed antidote to shifting baseline syndrome, representing the process of normalizing environmental improvement rather than degradation. This concept suggests that societies can reset their expectations upward, making clean rivers and healthy ecosystems the new standard that each generation seeks to maintain or exceed. Macfarlane uses the recovery of the Elwha River in Washington State as an example of how quickly natural systems can regenerate when given the opportunity, demonstrating that environmental restoration can happen rapidly enough to shift baselines within a single generation. The concept offers hope that environmental consciousness can be redirected toward positive change rather than simply accepting ongoing decline.

Mauri is a Maori concept meaning “life principle,” “vital essence,” or “spiritual energy” that Macfarlane connects to his exploration of river consciousness. In Māori worldview, mauri represents the life force that flows through all natural entities, making them living beings rather than inanimate objects. The concept plays a central role in New Zealand’s Te Awa Tupua Act, which legally recognizes the Whanganui River as possessing mauri and therefore deserving of rights and protection. Macfarlane links mauri to the Latin concept of anima, showing how different cultures have developed similar understandings of the spiritual dimension that animates natural systems like rivers.

The more-than-human encompasses all forms of life and natural phenomena that exist beyond human experience and control, including animals, plants, rivers, forests, and ecological systems. Macfarlane uses this term to challenge anthropocentric worldviews that place humans at the center of existence and instead emphasizes the agency, intelligence, and rights of non-human entities. The concept suggests that the natural world possesses forms of consciousness, communication, and intentionality that humans must learn to recognize and respect rather than dismiss or exploit. In the context of the book, relating to the more-than-human world requires developing new forms of attention, language, and legal frameworks that can acknowledge the personhood and rights of entities like rivers and forests.

Over-abstraction refers to the excessive removal of water from natural sources such as rivers, springs, and aquifers that exceeds the rate at which these water systems can naturally replenish themselves. In the prologue, Macfarlane identifies over-abstraction as a critical threat to the survival of chalk streams and other water ecosystems, as growing urban populations and industrial demands have led to unsustainable extraction practices. This process depletes underground water tables and reduces the flow of springs and streams, ultimately threatening the ecological balance that has sustained these water systems for thousands of years. The author presents over-abstraction as one of the primary human activities that transforms rivers from living entities into mere resources to be consumed, illustrating the broader tension between treating water as a commodity versus recognizing it as a vital, animate part of the natural world.

The Rights of Nature movement is a global legal and activist campaign that seeks to establish legal personhood and rights for natural entities such as rivers, mountains, and forests. Macfarlane traces the movement’s intellectual origins to Christopher Stone’s 1972 paper “Should Trees Have Standing?” and its practical development through cases like New Zealand’s recognition of the Whanganui River as a legal person. The movement represents what Macfarlane calls a “legal ‘grammar of animacy’” (30)—referencing Robin Wall Kimmerer’s term—which attempts to align legal structures with worldviews that recognize nature as alive and deserving of protection. Through court cases and legislation worldwide, the movement challenges anthropocentric legal systems that treat natural entities as property rather than as beings with inherent rights and agency.

Shifting baseline syndrome describes the process by which each generation accepts environmental degradation as normal because they measure decline against an already diminished standard rather than historical baselines. Macfarlane uses this concept to explain how the gradual destruction of English rivers has been normalized over time, with each generation accepting dirtier, more polluted waterways as the new normal. The syndrome functions as a form of “generational amnesia” that masks ongoing environmental harm by preventing people from recognizing the full extent of what has been lost (23). Macfarlane argues that this psychological process has enabled the systematic degradation of river systems by making catastrophic decline appear gradual and acceptable rather than shocking and unacceptable.