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Atkins argues 'that entropy is an objective physical property, not an aspect of the observer's mind'

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Atkins argues 'that entropy is an objective physical property, not an aspect of the observer's mind' what is the evidence and justification for this from other source

Based on the provided sources, several authors and arguments support P.W. Atkins’ view that entropy is an objective physical property, refuting the idea that it is merely a measure of observer ignorance or a subjective mental construct.

Here is the evidence and justification for this objective interpretation found in the collection:

1. The Argument from Experimental Consistency (Calorimetry vs. Spectroscopy)

The strongest evidence for objectivity cited in the sources is the precise agreement between two completely independent methods of determining entropy:

• Macroscopic Measurement (Calorimetry): Entropy is determined experimentally by measuring heat capacities (Cp​) and phase changes from near absolute zero up to a specific temperature. This method relies purely on thermodynamic measurements of heat transfer[1].

• Microscopic Calculation (Spectroscopy): Entropy is calculated using the Boltzmann formula (S=klnW) based on quantum mechanical energy levels determined via spectroscopy.

• The Justification: As noted in Tame and Denbigh, the fact that these two distinct techniques—one measuring bulk heat properties and the other measuring atomic energy levels—yield “within-error-identical values” for gases (like argon or OCS) is “irrefutable proof that entropy is indeed an objective property”[5][6]. If entropy were merely a measure of “human ignorance,” such precise numerical agreement between unrelated physical methods would be inexplicable[3].

2. The Argument from Physical Mechanism (Energy Dispersal)

Several authors argue that entropy describes a concrete physical process—the spreading of energy—rather than a mental state of uncertainty.

• **Energy Spreading:**Lambert and Leff argue that entropy measures the dispersal of energy over accessible microstates. This dispersal is a physical event (e.g., a gas expanding or heat spreading) that occurs regardless of whether an observer is watching[7].

• **Objective Constraints:**Wicken argues that thermodynamic uncertainty is “fundamental” and objective because it arises from the stochastic nature of matter, not the observer’s lack of data. A system physically fluctuates among microstates; this is an intrinsic property of the system, unlike the “uncertainty” in Information Theory, which vanishes once a message is received[10][11].

3. The “Secondary Quality” Defense (Denbigh)

K.G. Denbigh (defended and critiqued by Price) argues that entropy is objective in the same way other physical properties are.

• Public Agreement: Denbigh argues that entropy is “fully objective” because its value can be publicly agreed upon by observers performing standard measurements (like the freezing point of water or heat capacity), similar to how we agree on the length of a rod[12].

• Independence from Mind: Denbigh explicitly rejects the “subjectivist” view (often associated with Jaynes) that entropy depends on what an observer chooses to measure. He argues that the entropy of a system is determined by its physical specification (pressure, temperature, etc.), not by the observer’s state of mind[5][15].

4. Rejection of Anthropomorphism in Quantum Mechanics

Planck, Wicken, and Tame provide arguments rooted in quantum mechanics to counter the “anthropomorphic” (human-centered) view.

• **Quantization:**Tame notes that the “coarse-graining” required to calculate entropy is not an arbitrary human choice but is imposed by nature itself (Planck’s constant, h). Nature limits the precision of states via the Uncertainty Principle, making the number of microstates (W) an objective physical count, independent of human knowledge[16][17].

• **Rejection of “Missing Information”:**Ben-Naim (despite believing entropy is information) notes that standard thermodynamic entropy is a “state function.” A system in a specific state has a specific entropy value regardless of what anyone knows about it. He critiques the “scattering of pages” analogy for entropy because it implies a reader is necessary to distinguish order from disorder; physical entropy exists without the reader[18][19].

5. Biological and Evolutionary Independence

Authors discussing biology argue that entropy must be objective because it drives physical evolution independent of humans.

• **Evolutionary Reality:**Wicken and Volkenstein emphasize that organisms evolved long before humans existed. If entropy were merely “human ignorance,” the thermodynamic processes driving biological evolution and the “heat death” of the universe would have no physical basis without a human observer[20][21].

• Popper’s Critique: Cited by Tame, Karl Popper argued it is “absurd” to believe that physical events (like a gas expanding) happen because of our ignorance. The physical world dissipates energy regardless of whether we are looking at it[22].

Summary of Justifications

Argument TypeJustification for Objectivity
EmpiricalCalorimetric and spectroscopic measurements yield the same numerical value for entropy, proving it is a physical property, not a mental estimate[5].
MechanisticEntropy measures energy dispersal (spreading), which is a physical process occurring in nature independent of observation[23].
QuantumThe counting of states (W) is fixed by physical constants (Planck’s constant), not by arbitrary human choice[17].
CausalEntropy changes drive spontaneous processes (like chemical reactions and evolution) that occurred long before human observers existed[21][24].

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