how consciousness changes the world

Living on Earth: Life, Consciousness and the Making of the Natural World Peter Godfrey-Smith William Collins (2024)

Philosopher Peter Godfrey-Smith has devoted his career to examining how animal minds evolved. He blends formidable analytical skills with a deep curiosity about the natural world, mostly experienced at first hand in his native Australia. While writing his latest book, Living on Earth, he spent many hours scrutinizing noisy parrots and cockatoos in his back garden, weeks observing gobies building underwater towers made of shells and seaweed and years closely watching how octopuses behave (P. Godfrey-Smith et al. PLoS ONE 17, e0276482; 2022). The result is an inclusive perspective on Earth’s many distinct minds and agents that urges readers to consider humans’ collective choices and their diverse consequences.

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Living on Earth offers an extended philosophical meditation on life, mind, the world and our place in it, completing a trilogy of works on the nexus of agency, sensation and felt experience. His 2016 book Other Minds explored octopus cognition and evolution. And Metazoa (2020) appraised the subjective experiences of animals, concluding that there exists an “animal way of being” that arises from the integration of sensory information in nervous systems. This implies that sentience and subjectivity — life-shaping combinations of perception, goals and values — are widespread across the tree of life.

In his latest book, the author casts his net wider still, asking how the minds and agency of living things have affected Earth. “The history of life is not just a series of new creatures appearing on the stage,” he notes. “The new arrivals change the stage itself.”

The arrival of animals

Godfrey-Smith starts by explaining how the earliest lifeforms altered our planet’s chemistry and geology. Photosynthetic bacteria released oxygen, which gradually blanketed Earth and left their mark on the composition of rocks and minerals in the form of new minerals, such as malachite. Eventually, enough oxygen accumulated to power the evolution of aerobic life — a stark example of the transformative impact of some lineages constructing environments in which others can thrive.

The arrival of animals that could undertake purposeful actions, such as feeding, interacting with others and gathering information, meant that Earth was transformed further. As their capacities for controlled movement evolved, animals became able to actively engineer their environments. Defecating migrating whales, for instance, redistribute nutrients and support other species in the food web, which in turn benefits the whales.