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Do living organisms violate the 2nd law of thermodynamics?


“The more the universe seems comprehensible, the more it also seems pointless” - Steven Weinberg


Throughout human history, a profound and abstract question has united biologists, philosophers, physicists, and the general populace across millennia: What is the purpose of life, and by extension, the universe itself?


One prevailing notion in Physics is that the universe's purpose may revolve around increasing entropy. Entropy, within the context of physics, quantifies the level of disorder in a given system. More precisely, it represents the thermal energy per unit temperature that cannot be harnessed for useful work. Think of it as energy dissipating into the surroundings, the reason no system can achieve 100% energy efficiency.


The Second Law of Thermodynamics asserts that the entropy of the entire universe, considered as a closed system, will consistently rise over time. This is why an ice cube left at room temperature gradually melts, and why we inevitably age without reversing the process. However, as one contemplates more instances of increasing entropy, it becomes evident that there are apparent counterexamples and exceptions. For instance, although an ice cube melts at room temperature, we can certainly refreeze it, seemingly defying the trend of increasing entropy.


The existence of life on Earth, and potentially elsewhere in the universe, appears to challenge the Second Law of Thermodynamics directly. Specifically, it is the evolutionary progression of life that often fuels this argument. In the process of evolution, organization and complexity increase, which contradicts the Second Law of Thermodynamics, stating that things tend to become more disordered with time. In his book ‘What is Life?’, physicist Erwin Schrödinger (yes, that one with the cat) argues that this paradox is resolved through analysing the definition of the Second Law of Thermodynamics. He argues that entropy increases within a closed system, where heat cannot enter or exit. Earth, however, is not a truly closed system because it continually receives solar energy from the sun. The physical and chemical processes that enable life, such as photosynthesis, demonstrate that living systems operate as open systems. Therefore, life is compatible with the Second Law of Thermodynamics.


It is worth noting that life, as we know it, doesn't exist in isolation. Earth itself is part of a vast universe, and the emergence of life here could be seen as a localised phenomenon within a broader cosmic context. This perspective raises the question of whether life's existence on Earth, with its apparent defiance of entropy, might be part of a grander cosmic scheme we have yet to fully comprehend. Perhaps the universe's ultimate purpose, if any, involves more than simply increasing entropy, and the emergence of life, as complex and intricate as it is, could be a fascinating chapter in a story that transcends the boundaries of our current understanding of physics and biology, to increase complexity of computational power. Alternatively, it's possible, as Steven Weinberg suggests, that the universe lacks inherent purpose and is the product of anextraordinarily fortuitous situation, from the precise values of fundamental constants to the ideal conditions on Earth that facilitated abiogenesis.


The interplay between science, philosophy, and the mysteries of the universe continues to inspire and challenge our perception of purpose and order.


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