Re: 2nd law clarifications

On 2/01/2025 5:53 pm, MarkE wrote:

Local entropy can decrease in an open system with an input of free energy.
 Free energy alone is not sufficient to maintain or further decrease low local entropy: an energy capture and transformation mechanism is also needed.
 Extant life *maintains* low local entropy through its organisation and processes.
 Evolving life *decreases* low local entropy through the ratcheting mechanism natural selection acting on random mutations in instances where that evolution increases functional complexity and organisation.
 There is no other known mechanism apart from natural selection that does this. For example, neutral drift alone increases entropy.

Out of interest, AI's assessment:
Prompt: Comment on/critique the following statements:
ChatGPT 4o: Here’s a critique and commentary on each of the provided statements:
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1. "Local entropy can decrease in an open system with an input of free energy."
• Commentary:
o This statement is consistent with the second law of thermodynamics, which applies universally to closed systems but allows for local decreases in entropy in open systems. Living systems (and prebiotic systems) are open systems that exchange energy and matter with their surroundings, allowing for local entropy reduction.
o Examples include crystallization (where heat is released to the environment) and the maintenance of biological order in living cells.
• Critique:
o The statement is accurate but could benefit from clarity. It may be helpful to specify that while entropy can locally decrease, the overall entropy of the system and its surroundings increases. This avoids misinterpretation by those unfamiliar with thermodynamic principles.
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2. "Free energy alone is not sufficient to maintain or further decrease low local entropy: an energy capture and transformation mechanism is also needed."
• Commentary:
o This is an excellent point. Free energy must be harnessed and converted into work to decrease entropy. For instance:
 Photosynthesis captures solar energy and transforms it into chemical energy.
 Proton gradients in mitochondria are used to synthesize ATP, the energy currency of cells.
o The emphasis on an energy capture and transformation mechanism highlights the importance of structure and function, such as enzymes and membranes, in enabling this process.
• Critique:
o This is well-stated and foundational to understanding how living systems operate. One addition could be an example from abiogenesis or early prebiotic systems, such as mineral surfaces catalyzing energy transformations, to provide more context for the origin of such mechanisms.
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3. "Extant life maintains low local entropy through its organisation and processes."
• Commentary:
o This statement is correct and captures the essence of how living organisms sustain order. Metabolic processes, such as catabolism and anabolism, continuously balance energy input and waste output to maintain low entropy.
o For example, cells use ATP to drive endergonic reactions, repair structures, and create macromolecules, maintaining their complex organization.
• Critique:
o While the statement is accurate, the term "low local entropy" might benefit from elaboration. For example, it could mention that this refers to the high degree of molecular organization and functional complexity seen in living systems.
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4. "Evolving life decreases low local entropy through the ratcheting mechanism of natural selection acting on random mutations in instances where that evolution increases functional complexity and organisation."
• Commentary:
o This is a strong statement linking natural selection to entropy reduction in an evolutionary context. Natural selection indeed acts as a "ratchet," favoring mutations that increase functional complexity and organization, leading to cumulative improvements in adaptation and order.
o Over evolutionary time, this process has resulted in increasingly complex systems, from single-celled organisms to multicellular life.
• Critique:
o The statement assumes that functional complexity always corresponds to lower entropy, which may need clarification. Complexity can increase without always leading to a direct reduction in entropy, depending on how "entropy" is defined in the context of information theory versus thermodynamics.
o The phrase "evolving life decreases low local entropy" could imply that entropy always decreases during evolution, which might not be true in all contexts. Evolution sometimes involves simplification (e.g., parasites losing unnecessary functions), which might not reduce entropy in the same way.
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5. "There is no other known mechanism apart from natural selection that does this. For example, neutral drift alone increases entropy."
• Commentary:
o Natural selection is indeed the primary mechanism known to consistently decrease entropy in the sense of increasing functional complexity and organization. Neutral drift, by contrast, is a stochastic process that can result in changes that are functionally neutral or even degrade complexity over time (increasing "entropy").
o For instance, in the absence of selection, drift can lead to the accumulation of deleterious mutations, increasing disorder in the genome.
• Critique:
o The claim that "neutral drift alone increases entropy" is oversimplified. While drift can increase genetic entropy (in the sense of loss of function), it can also lead to new forms of complexity under specific conditions. For example, neutral mutations can set the stage for exaptation or co-option by selection later on.
o It might be worth acknowledging that other mechanisms, like epigenetic changes, gene duplication, or horizontal gene transfer, can contribute to functional complexity. While these processes often work alongside natural selection, they sometimes operate semi-independently.
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Overall Critique and Suggestions:
The statements are well-thought-out and provide a solid conceptual framework for discussing entropy, evolution, and natural selection. However:
1. Clarity and Scope: Some terms (e.g., "low local entropy") could be defined more explicitly to avoid ambiguity, particularly for readers without a strong background in thermodynamics or biology.
2. Acknowledging Edge Cases: While natural selection is central to reducing entropy in evolving life, processes like neutral drift or simplification could be better nuanced to address exceptions.
3. Inclusion of Early Life Examples: Tying some points to prebiotic systems or the origin of life (e.g., energy capture in early protocells) would enhance the discussion's relevance to abiogenesis.
The overall framework is solid, and with minor adjustments, it would be even more precise and comprehensive.