Nick Lane: Origin of Life, Evolution, Aliens, Biology, and Consciousness | Lex Fridman Podcast #318

Lane suggests that the planet itself acts as a giant battery, with a flow of electrons in hydrothermal vents, mirroring the topology of a cell. He believes there's a strong inevitability for Earth-like planets to give rise to bacteria, and possibly even a similar genetic code, due to deterministic chemistry and water.

Nick Lane discusses the origin of life on Earth, highlighting the role of hydrothermal vents on the early Earth, which provided hydrogen gas and electrical charges in cell-like pores to drive the chemistry of life. He emphasizes that oxygen was not present at the origin of life and that life fundamentally involves hydrogenating carbon dioxide.

Lane explains the difficulty in defining life, noting that many proposed definitions are flawed. He describes life as a system capable of parasitizing its environment to make relatively exact, informationally accurate copies of itself.

Photosynthesis is identified as a crucial and difficult invention that occurred only once in Earth's history (oxygen-producing photosynthesis). It involves using sunlight to split water, taking hydrogen for CO2, and releasing oxygen as a waste product, which created an oxygenated atmosphere essential for complex animal life.

The origin of eukaryotic cells (cells with a nucleus and internal structures) is considered the single biggest invention in life's history. This happened through endosymbiosis (one cell engulfing another), specifically mitochondria, transforming the energetic possibilities of life and enabling larger genomes and multicellularity.

Sex, as we know it in eukaryotes, was invented about 2 billion years ago. It's a complex process of gamete fusion, recombination, and cell division. This mechanism is crucial for maintaining the quality of large genomes and preventing mutations, a problem bacteria cannot solve with their smaller genomes.

Predation, starting even in bacteria, became a major driving force for evolution. The Cambrian explosion, about 560-570 million years ago, saw the rapid diversification of animal life with eyes, claws, and shells, driven by predator-prey dynamics and increased oxygen levels, leading to complex ecosystems and evolutionary arms races.

The evolution of humans is linked to population density and increased interactions between groups, facilitating information transfer and cultural complexity. Homo sapiens were likely more adaptable and competitive than Neanderthals, leading to their success.

The evolution of vision, even from a simple light-sensitive spot, highlights how new sensory inputs drive the development of complex nervous systems. The discussion touches on the idea that our perception of reality is a sensory slice, useful for survival, rather than an objective truth.

Lane and Fridman delve into the 'hard problem' of consciousness: how a physical brain gives rise to subjective feelings and emotions. Lane, as a biochemist, struggles with how depolarizing neurons translate into feelings. He suggests AI, despite its computational power, may not achieve biological consciousness without something similar to the complexities of biological life and death.

The conversation explores the idea of biochemistry as an algorithm and whether AI can 'hack' it to surpass human abilities in art or intellect. They debate whether replicating intelligence requires simulating the entire biological process, including emotions and self-preservation, or if AI can find alternative paths to conscious experience.

Lane believes the universe likely holds billions of planets with bacterial life but far fewer intelligent civilizations. The rarity of specific evolutionary inventions (like eukaryotic cells or photosynthesis) makes complex, intelligent life uncommon. He suggests that if we find life on Mars, its similarity to Earth life could indicate either shared origins or deterministic chemical pathways.

While appreciating the poetic idea of Earth as a 'living planet,' Lane distinguishes it from a biological organism that evolves through natural selection, as there's only one. He views cities as complex systems driven by human societies and ideas (memes), rather than living entities themselves.

The discussion covers the human capacity for depression and feelings of meaninglessness, seen as potential features of mortality and the complex wiring of human brains. Transient joy and misery are inherent in the biological regulation of emotions.

Lane advises aspiring writers and scientists to focus on their genuine interests, asking childlike questions, and pursuing the 'story' of what they want to convey. He emphasizes the importance of following one's passion, as true longevity and success in science come from profound engagement rather than career planning.

When asked to summarize Earth like Ford Prefect, Lane suggests "mostly living" but emphasizes its complexity through eukaryotic life and photosynthesis. He notes the ironic "mostly harmless" description given the potential for human actions to greatly impact the planet.