Bacteria to Buddha: Read an exclusive excerpt from Ramanan Laxminarayan’s new book

The book traces how our evolution was shaped by consciousness, and explores research across neuroscience, evolutionary biology, philosophy and religion.

Every living thing, from the simplest cell to the human brain, exists only by virtue of its ability to register and respond to the world beyond its boundaries. Life began, quite literally, at the interface between inside and outside – at the thin membrane that separated the organism from its surroundings yet kept it in constant conversation with them. Through that boundary flowed everything that mattered: energy, information, and the signals of threat or nourishment.

Consciousness is not a thing that life has but the way life listens. The single-celled amoeba senses gradients of light and sugar, a worm feels vibration and adjusts its motion; a bird detects magnetic fields as guidance; and we, at the summit of this sensitivity, translate sensation into meaning. What began as chemical responsiveness evolved into perception, then cognition, then imagination. At each turn, the purpose remained the same: to meet the world more effectively, to anticipate its changes, to survive within its vast unpredictability.

To be conscious, therefore, is to be in dialogue, not merely to observe the environment but to participate in its unfolding. Even the arrangement of our nervous system records this history: layers of older, instinctual circuits overlaid by newer networks of planning and abstraction. Human consciousness does not replace the older responses; it refines them. Our emotions are ancient alarms and our reasoning mind is the interpreter that arrived later, adding narrative to instinct. Consciousness is evolution’s palimpsest – layer upon layer of adaptive response, each built upon the residue of earlier forms of knowing.

The difference between life and matter is not that one moves and the other does not but that one remembers its encounters. Every act of perception, from the flicker of a microbe to the self-reflection of a poet, is life rehearsing its relationship with what lies outside. Across time, those rehearsals accumulate into wisdom. The evolution of consciousness is the story of responsiveness becoming reflection – the long refinement of survival into awareness, and of awareness into wonder. And it took place in steps, building up in stages over billions of years.

(Excerpted with permission from Bacteria to Buddha by Ramanan Laxminarayan, published by Hachette India; 2026)