Evidence record
Does information weigh anything?
Every sentence on the exploration belongs to at least one claim below. Each says what kind of statement it is, what it rests on, what the evidence does not establish, and how far it was checked. Nothing here is a score, and none of it is a verdict on a belief or a theory.
Last checked 24 September 2026.
- Source checked: 37
- A judgement, not a fact: 6
If something here is wrong, misquoted, out of date or unfair, write to support@unknownoceans.com and give the claim number, which does not change.
What the question takes for granted
A physics question put as a metaphor: "weigh" is read as "cost", and the page answers that erasing information has a minimum cost in heat, then separates that measured result from stronger claims that the world is made of information.
Information is always carried by some physical system
Established
Landauer’s argument places each bit in a physical system with states for zero and one; the experiments build such a memory.
A cost in energy is the sense in which information could "weigh" anything
Open
The page reads the question this way and does not discuss mass; that reading is the page’s choice.
The second law holds for the demon too
Contested
The standard resolution assumes the demon’s memory is a physical system inside thermodynamics; Earman and Norton argue that this assumption does the work by itself.
How the question is labelled
Claim: The cost of forgetting
- Kind
- Framing. Signposting. It asserts nothing a source could check.
Claim: Information
- Kind
- Framing. Signposting. It asserts nothing a source could check.
The question
Claim: Erasing one bit releases a minimum quantity of heat.
- Kind
- What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Information and thermodynamics: experimental verification of Landauer’s erasure principlesection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field
The source reads: It states that any logically irreversible transformation of classical information is necessarily accompanied by the dissipation of at least kBT ln 2 of heat per lost bit
Supports
Irreversibility and Heat Generation in the Computing Processsection 4, p. 187
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: the number of states covered in the ensemble has been cut in half. The entropy therefore has been reduced by k loge 2 = 0.6931 k per bit ... this entropy must appear elsewhere as a heating effect, supplying 0.6931 kT per restored bit to the surroundings.
What this does not establish
The principle sets a floor, not a fixed amount: erasure in practice releases more. The floor applies to a memory in contact with a heat bath at one temperature.
Other readings
Norton and Shenker question whether heat generation must accompany logically irreversible operations at all, arguing that the entropy in the standard derivation is not thermodynamic entropy; the Stanford Encyclopedia reports the debate.
Later work looked for
How the principle is stated; not a finding later work revises.
Claim 3 · checked 24 September 2026 · AI-assisted audit
Claim: It was predicted in 1961 and measured in 2012.
- Kind
- Historical claim. A statement about the past that historical evidence can test.
- Review
- Source checked. The cited passage was read, and it says this.
"Predicted" is Landauer’s 1961 argument; "measured" is the first direct experimental test, published in Nature in 2012.
Supports
Irreversibility and Heat Generation in the Computing Processsection 4, p. 187
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: the number of states covered in the ensemble has been cut in half. The entropy therefore has been reduced by k loge 2 = 0.6931 k per bit ... this entropy must appear elsewhere as a heating effect, supplying 0.6931 kT per restored bit to the surroundings.
Supports
Experimental test of Landauer’s principle in single-bit operations on nanomagnetic memory bitsIntroduction
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Review of the field
The source reads: The first direct experimental test of Landauer’s principle was reported in 2012 using a 2-μm glass bead in water manipulated in a double-well laser trap as a model system
Context
Experimental verification of Landauer’s principle linking information and thermodynamicsabstract
Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026 · Physical systems · Experiment
The source reads: Using a system of a single colloidal particle trapped in a modulated double-well potential, we establish that the mean dissipated heat saturates at the Landauer bound in the limit of long erasure cycles.
The Nature report of the experiment, read as its abstract only.
Claim 4 · checked 24 September 2026 · AI-assisted audit
Claim: Information is not an abstraction floating above physics.
- Kind
- This page’s reading. A judgement the page makes from the evidence. Others read it differently.
- Review
- A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.
The page’s reading of Landauer’s principle: a constraint deduced from logic binds any physical system that carries the logic out.
Context
Information Processing and Thermodynamic Entropysection 1.3, Landauer’s principle
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: Landauer's argument suggests that, purely from the abstract properties of a logical operation one can deduce a thermodynamic constraint upon any physical system which is required to act as an embodiment of that logical operation.
Other readings
Norton and Shenker question whether heat generation must accompany logically irreversible operations at all, arguing that the entropy in the standard derivation is not thermodynamic entropy; the Stanford Encyclopedia reports the debate.
Claim 5 · checked 24 September 2026 · AI-assisted audit
Claim: Erasing it has an unavoidable thermodynamic cost
- Kind
- What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Information Processing and Thermodynamic Entropysection 1.3, Landauer’s principle
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: Bennett's presentation of Landauer's principle rapidly became accepted as the fundamental principle of the thermodynamics of computation.
Supports
Information and thermodynamics: experimental verification of Landauer’s erasure principlesection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field
The source reads: It states that any logically irreversible transformation of classical information is necessarily accompanied by the dissipation of at least kBT ln 2 of heat per lost bit
Qualifies
Information Processing and Thermodynamic Entropysection 4
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: focussed upon whether heat generation must necessarily be associated with logically irreversible operations ... Norton argued in detail that this is an illegitimate calculation, and that the resulting entropy has nothing to do with thermodynamic entropy.
Other readings
Norton and Shenker question whether heat generation must accompany logically irreversible operations at all, arguing that the entropy in the standard derivation is not thermodynamic entropy; the Stanford Encyclopedia reports the debate.
Later work looked for
Crossref, 2017 on, "Landauer principle experimental erasure": the bound has since been tested in a feedback trap (Jun and others 2014) and in nanomagnetic bits (Hong and others 2016), both consistent with it; nothing found that overturns it. A 2026 Physical Review Letters record on shifting erasure cost below the bound with a "demon-biased" bath was seen as a title only.
Claim 6 · checked 24 September 2026 · AI-assisted audit
Claim: which sets a floor under any computation that throws information away
- Kind
- What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Notes on Landauer’s principle, reversible computation, and Maxwell’s Demonsection 1, Landauer’s Principle
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: it is possible to reprogram any deterministic computation as a sequence of logically reversible steps, provided the computation is allowed to save a copy of its input.
Supports
Information Processing and Thermodynamic Entropysection 4
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: The increasingly explicit models developed by workers such as Bennett, Fredkin and Toffoli have now generally been considered to have established that thermodynamically reversible computation is indeed possible, if implemented by logically reversible computers.
What this does not establish
The floor applies to logically irreversible steps. A computation written as logically reversible steps escapes it in principle, as Bennett shows.
Later work looked for
How the principle is stated; not a finding later work revises.
Claim 7 · checked 24 September 2026 · AI-assisted audit
Claim: and is the standard answer to a paradox about the second law that had stood for more than a century.
- Kind
- Historical claim. A statement about the past that historical evidence can test.
- Review
- Source checked. The cited passage was read, and it says this.
From Maxwell’s letter of 1867 to Bennett’s resolution of 1982 is more than a century; Penrose’s of 1970 is just over.
Supports
Information Processing and Thermodynamic Entropysection 1.1, Maxwell’s demon
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: Maxwell's demon was first mentioned in a letter written to Tait in 1867.
Supports
Information Processing and Thermodynamic Entropysection 3.3, Memory and erasure
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: If the demon's memory is finite, eventually it will run out of space ... the demon must reset some of its memory back to zero, which requires a corresponding increase in Boltzmann entropy elsewhere. Penrose's solution was effectively rediscovered independently by Bennett (1982)
Supports
Information Processing and Thermodynamic Entropysection 1.3, Landauer’s principle
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: Bennett's presentation of Landauer's principle rapidly became accepted as the fundamental principle of the thermodynamics of computation.
Other readings
Earman and Norton argue that the principle is either unnecessary or insufficient to answer the demon; claim 42 and claim 43 report it.
Corrected
24 September 2026. Previously: “and is the standard answer to a paradox about the second law that had stood for the better part of a century.” Maxwell’s demon dates from a letter of 1867 and the standard answer from Penrose in 1970 and Bennett in 1982, so the paradox stood for more than a century, not most of one (Stanford Encyclopedia, sections 1.1 and 3.3).
Claim 8 · checked 24 September 2026 · AI-assisted audit
Claim: In the twentieth century, physicists as eminent as von Neumann, Gabor and Brillouin believed that every elementary step of information processing had an unavoidable cost in heat.
- Kind
- Historical claim. A statement about the past that historical evidence can test.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Notes on Landauer’s principle, reversible computation, and Maxwell’s Demonsection 3, Landauer’s principle in the context of other ideas
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026
The source reads: a misconception that many people have fallen into during the 20’th century, including giants like von Neumann, Gabor, and Brillouin ... This is the informal belief that there is an intrinsic cost of order kT for every elementary act of information processing
Supports
Information Processing and Thermodynamic Entropysection 1.3, Landauer’s principle
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: von Neumann (1949) had also suggested on the basis of Szilard's work, that every act of information processing was necessarily accompanied by this level of energy dissipation.
Corrected
24 September 2026. Previously: “Computation is usually thought of as free in principle and expensive only in practice, because of imperfect engineering.” The old sentence named no one and reversed the history: Bennett and the Stanford Encyclopedia both record that von Neumann, Gabor and Brillouin held that every elementary act of information processing costs of order kT.
Claim 9 · checked 24 September 2026 · AI-assisted audit
Claim: Measuring and copying turned out to be free in principle.
- Kind
- What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Information Processing and Thermodynamic Entropysection 1.3; section 4
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: In (Bennett 1982) he argued that measurement could also be represented by a logically reversible process, avoiding any need to generate heat.
Supports
Information Processing and Thermodynamic Entropysection 4
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: The increasingly explicit models developed by workers such as Bennett, Fredkin and Toffoli have now generally been considered to have established that thermodynamically reversible computation is indeed possible, if implemented by logically reversible computers.
Supports
Notes on Landauer’s principle, reversible computation, and Maxwell’s Demonsection 3, Landauer’s principle in the context of other ideas
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: Landauer’s principle, while perhaps obvious in retrospect, makes it clear that information processing and acquisition have no intrinsic, irreducible thermodynamic cost, whereas the seemingly humble act of information destruction does have a cost, exactly sufficient to save the Second Law from the Demon.
Supports
Notes on Landauer’s principle, reversible computation, and Maxwell’s Demonsection 3, Landauer’s principle in the context of other ideas
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: Thus measurement and copying can be intrinsically irreversible, but only when they are conducted in such a way as to overwrite previous information.
What this does not establish
Free in principle means no minimum set by physics, for an ideal slow process; every real device dissipates.
Later work looked for
Crossref, 2017 on, "reversible computation thermodynamics": nothing found that revises the reference work’s account.
Corrected
24 September 2026. Previously: “” Added with the corrected first sentence of the opening, so that the contrast it sets up is the one Bennett draws.
Claim 10 · checked 24 September 2026 · AI-assisted audit
Claim: One operation is not, and it is the humblest: throwing something away.
- Kind
- What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
- Review
- Source checked. The cited passage was read, and it says this.
"Throwing something away" is erasure: resetting a memory to a fixed state.
Supports
Notes on Landauer’s principle, reversible computation, and Maxwell’s Demonsection 3, Landauer’s principle in the context of other ideas
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: Landauer’s principle, while perhaps obvious in retrospect, makes it clear that information processing and acquisition have no intrinsic, irreducible thermodynamic cost, whereas the seemingly humble act of information destruction does have a cost, exactly sufficient to save the Second Law from the Demon.
Context
Information Processing and Thermodynamic Entropysection 1.3, Landauer’s principle
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: To quantify the heat generation Landauer considered the most basic logically irreversible operation to be resetting a bit.
What this does not establish
Strictly the cost falls on every logically irreversible operation, of which resetting a bit is the simplest.
Later work looked for
How the principle is stated; not a finding later work revises.
Corrected
24 September 2026. Previously: “One operation is not free even in principle, and it is the one nobody thinks about: throwing something away.” "Nobody thinks about" was an unsupported generalisation; Bennett calls erasure "the seemingly humble act of information destruction".
Claim 11 · checked 24 September 2026 · AI-assisted audit
What has been shown
Claim: What has been shown
- Kind
- Framing. Signposting. It asserts nothing a source could check.
The principle
Claim: The principle
- Kind
- Framing. Signposting. It asserts nothing a source could check.
Claim: In 1961 Rolf Landauer argued that logically irreversible operations, those that map two different inputs to the same output, must dissipate energy.
- Kind
- An argument. An argument a named thinker makes. That it is made is checked; whether it succeeds is argued.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Irreversibility and Heat Generation in the Computing Processabstract, p. 183
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: It is argued that computing machines inevitably involve devices which perform logical functions that do not have a single-valued inverse. This logical irreversibility is associated with physical irreversibility and requires a minimal heat generation, per machine cycle, typically of the order of kT for each irreversible function.
Supports
Irreversibility and Heat Generation in the Computing Processsection 3, Logical irreversibility, p. 185
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: We shall call a device logically irreversible if the output of a device does not uniquely define the inputs.
Supports
Notes on Landauer’s principle, reversible computation, and Maxwell’s Demonsection 1, Landauer’s Principle
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026
The source reads: In his classic 1961 paper [2], Rolf Landauer attempted to apply thermodynamic reasoning to digital computers.
Claim 14 · checked 24 September 2026 · AI-assisted audit
Claim: Erasing a bit reduces the number of states the system can be in, and that reduction has to be paid for in heat released to the environment.
- Kind
- What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Irreversibility and Heat Generation in the Computing Processsection 4, p. 187
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: the number of states covered in the ensemble has been cut in half. The entropy therefore has been reduced by k loge 2 = 0.6931 k per bit ... this entropy must appear elsewhere as a heating effect, supplying 0.6931 kT per restored bit to the surroundings.
What this does not establish
Landauer adds that his reasoning "gives no guarantee that this minimum is in fact achievable"; later experiments approached it.
Other readings
Norton and Shenker question whether heat generation must accompany logically irreversible operations at all, arguing that the entropy in the standard derivation is not thermodynamic entropy; the Stanford Encyclopedia reports the debate.
Later work looked for
How the principle is stated; not a finding later work revises.
Claim 15 · checked 24 September 2026 · AI-assisted audit
Claim: The minimum is small: at room temperature, about three zeptojoules per bit.
- Kind
- What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Information and thermodynamics: experimental verification of Landauer’s erasure principlesection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory
The source reads: This quantity represents only ∼ 3 × 10⁻²¹ J at room temperature (300 K)
Notation restored: Superscript restored from the authors’ LaTeX source on arXiv (1503.06537v1), which gives the exponent as −21, read 2026-09-24. The text as extracted reads: This quantity represents only ∼ 3× 10−21 J at room temperature (300 K)
Supports
Experimental test of Landauer’s principle in single-bit operations on nanomagnetic memory bitsIntroduction
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory
The source reads: This energy, kBT ln(2), corresponds to a value of 2.8 zJ (2.8 × 10⁻²¹ J) at 300 K.
Notation restored: Superscript restored from the Europe PMC full-text XML (PMC4795654), where the exponent is marked as a superscript, read 2026-09-24. The text as extracted reads: This energy, kBT ln(2), corresponds to a value of 2.8 zJ (2.8 × 10−21 J) at 300 K.
What this does not establish
A calculated value, kT ln 2 at 300 K (2.8 zeptojoules in Hong and others), not a measurement.
Later work looked for
How the principle is stated; not a finding later work revises.
Claim 16 · checked 24 September 2026 · AI-assisted audit
Claim: Today’s computers dissipate far more
- Kind
- Observation. Something measured or seen, as the named source reports it.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Experimental test of Landauer’s principle in single-bit operations on nanomagnetic memory bitsDiscussion
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: the significance of this result is that today’s computers are far from the fundamental limit and that future marked reductions in power consumption are possible
Supports
Notes on Landauer’s principle, reversible computation, and Maxwell’s Demonsection 2, Objections to Landauer’s Principle
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026
The source reads: Of course in practice almost all data processing is done on macroscopic apparatus, dissipating macroscopic amounts of energy far in excess of what would be required by Landauer’s principle.
Context
Irreversibility and Heat Generation in the Computing Processsection 1, Introduction, p. 183
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026
The source reads: Naturally the amount of heat generation involved is many orders of magnitude smaller than the heat dissipation in any practically conceivable device.
Landauer’s own comparison, made in 1961.
What this does not establish
The sources say "far from" and "far in excess"; they give no single ratio for today’s machines.
Later work looked for
Crossref, 2017 on, "Landauer limit computing energy efficiency": nothing read that brings practical computing near the bound.
Corrected
24 September 2026. Previously: “Real computers dissipate many orders of magnitude more, so the bound is not currently what limits anything.” "Many orders of magnitude" was Landauer’s comparison in 1961 and no source read gives a current figure; Hong and others 2016 say today’s computers are "far from the fundamental limit". "Not what limits anything" went beyond them.
Claim 17 · checked 24 September 2026 · AI-assisted audit
Claim: so the bound is not what currently limits them.
- Kind
- This page’s reading. A judgement the page makes from the evidence. Others read it differently.
- Review
- A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.
Follows from claim 17: power consumption limits computers (Hong and others), and what they consume is far above the bound.
Supports
Experimental test of Landauer’s principle in single-bit operations on nanomagnetic memory bitsDiscussion
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026
The source reads: Given that power consumption is the key issue that limits the continued improvement in digital computers
Supports
Experimental test of Landauer’s principle in single-bit operations on nanomagnetic memory bitsDiscussion
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: the significance of this result is that today’s computers are far from the fundamental limit and that future marked reductions in power consumption are possible
Claim 18 · checked 24 September 2026 · AI-assisted audit
Where the argument came from
Claim: Where the argument came from
- Kind
- Framing. Signposting. It asserts nothing a source could check.
Claim: The 1961 paper is about computing hardware rather than about philosophy.
- Kind
- Historical claim. A statement about the past that historical evidence can test.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Irreversibility and Heat Generation in the Computing Processabstract, p. 183
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: It is argued that computing machines inevitably involve devices which perform logical functions that do not have a single-valued inverse. This logical irreversibility is associated with physical irreversibility and requires a minimal heat generation, per machine cycle, typically of the order of kT for each irreversible function.
Claim 20 · checked 24 September 2026 · AI-assisted audit
Claim: It appeared in IBM’s research journal and opens on how fast and how compact computing circuits could get, and what sets the floor.
- Kind
- Historical claim. A statement about the past that historical evidence can test.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Irreversibility and Heat Generation in the Computing Processrunning footer, pp. 183 to 191
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: IBM JOURNAL • JULY 1961
Supports
Irreversibility and Heat Generation in the Computing Processsection 1, Introduction, p. 183
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: The search for faster and more compact computing circuits leads directly to the question ... What are the ultimate physical limitations on the progress in this direction?
Corrected
24 September 2026. Previously: “Landauer was working at IBM on how small and how fast a computer could get, and the question was what sets the floor.” No source read states Landauer’s employer; the paper itself carries the journal and its opening question, "faster and more compact computing circuits".
Claim 21 · checked 24 September 2026 · AI-assisted audit
Claim: His answer was that the floor is not in the electronics.
- Kind
- An argument. An argument a named thinker makes. That it is made is checked; whether it succeeds is argued.
- Review
- Source checked. The cited passage was read, and it says this.
Landauer’s minimum does not depend on the device or the rate; it comes from the operations performed.
Supports
Irreversibility and Heat Generation in the Computing Processsection 1, Introduction, p. 183
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: Our arguments, however, are more basic than this, and show that there is a minimum heat generation, independent of the rate of the process.
Supports
Irreversibility and Heat Generation in the Computing ProcessSummary, p. 191
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: This energy dissipation has an unavoidable minimum arising from the fact that the computer performs irreversible operations.
Claim 22 · checked 24 September 2026 · AI-assisted audit
Claim: It is in the logic: an operation that loses information about its input cannot be run backwards, and irreversibility in the logic forces dissipation in the physics.
- Kind
- An argument. An argument a named thinker makes. That it is made is checked; whether it succeeds is argued.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Irreversibility and Heat Generation in the Computing Processabstract, p. 183
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: It is argued that computing machines inevitably involve devices which perform logical functions that do not have a single-valued inverse. This logical irreversibility is associated with physical irreversibility and requires a minimal heat generation, per machine cycle, typically of the order of kT for each irreversible function.
Supports
Irreversibility and Heat Generation in the Computing ProcessSummary, p. 191
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: This energy dissipation has an unavoidable minimum arising from the fact that the computer performs irreversible operations.
Claim 23 · checked 24 September 2026 · AI-assisted audit
It was measured
Claim: It was measured
- Kind
- Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Information and thermodynamics: experimental verification of Landauer’s erasure principlesection 3.2
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: The mean dissipated heat decreases with the duration of the erasure procedure τ and approaches the Landauer’s bound kBT ln 2 for long times.
Later work looked for
Crossref, 2017 on, "Landauer principle experimental erasure": the bound has since been tested in a feedback trap (Jun and others 2014) and in nanomagnetic bits (Hong and others 2016), both consistent with it; nothing found that overturns it. A 2026 Physical Review Letters record on shifting erasure cost below the bound with a "demon-biased" bath was seen as a title only.
Claim 25 · checked 24 September 2026 · AI-assisted audit
Claim: In 2012 an experiment trapped a single microscopic bead in a double-well potential, used the two wells as the two states of a bit, and measured the heat released while the bit was erased.
- Kind
- Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Information and thermodynamics: experimental verification of Landauer’s erasure principleabstract; section 2.1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: a one-bit memory is constructed, using a system of a single colloidal particle trapped in a modulated double-well potential. We measure the amount of heat dissipated to erase a bit ... The particles are silica beads
Supports
Information and thermodynamics: experimental verification of Landauer’s erasure principlesection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026
The source reads: The results described in this article were partially presented in two previous articles
One of the two is the 2012 Nature paper; this is the authors’ open account of the same apparatus.
Context
Experimental verification of Landauer’s principle linking information and thermodynamicsabstract
Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026 · Physical systems · Experiment
The source reads: Using a system of a single colloidal particle trapped in a modulated double-well potential, we establish that the mean dissipated heat saturates at the Landauer bound in the limit of long erasure cycles.
The Nature report of the experiment, read as its abstract only.
What this does not establish
One colloidal silica bead, a micrometre in radius, in water; the erasure succeeded in most cycles rather than all, and the heat reported is averaged over many cycles.
Later work looked for
Crossref, 2017 on, "Landauer principle experimental erasure": the bound has since been tested in a feedback trap (Jun and others 2014) and in nanomagnetic bits (Hong and others 2016), both consistent with it; nothing found that overturns it. A 2026 Physical Review Letters record on shifting erasure cost below the bound with a "demon-biased" bath was seen as a title only.
Claim 26 · checked 24 September 2026 · AI-assisted audit
Claim: The slower the erasure, the closer the dissipated heat came to the predicted minimum, where it levelled off.
- Kind
- Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Information and thermodynamics: experimental verification of Landauer’s erasure principlesection 3.2
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: The mean dissipated heat decreases with the duration of the erasure procedure τ and approaches the Landauer’s bound kBT ln 2 for long times.
Supports
Information and thermodynamics: experimental verification of Landauer’s erasure principlesection 3.2
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: we find A = 0.72kBT which is close to kBT ln 2
Context
Experimental verification of Landauer’s principle linking information and thermodynamicsabstract
Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026 · Physical systems · Experiment
The source reads: Using a system of a single colloidal particle trapped in a modulated double-well potential, we establish that the mean dissipated heat saturates at the Landauer bound in the limit of long erasure cycles.
The Nature report of the experiment, read as its abstract only.
What this does not establish
The long-time value from a two-parameter fit was 0.72 kT against the bound’s 0.693 kT, and the heat is averaged over the cycles that ended in the erased state.
Later work looked for
Crossref, 2017 on, "Landauer principle experimental erasure": the bound has since been tested in a feedback trap (Jun and others 2014) and in nanomagnetic bits (Hong and others 2016), both consistent with it; nothing found that overturns it. A 2026 Physical Review Letters record on shifting erasure cost below the bound with a "demon-biased" bath was seen as a title only.
Corrected
24 September 2026. Previously: “The dissipated heat approached the predicted minimum as the erasure was performed more slowly, which is exactly the predicted behaviour.” "Exactly the predicted behaviour" overstated a fit that gave 0.72 kT against 0.693 kT with imperfect erasure (Berut and others 2015, section 3.2); the Nature abstract says the heat "saturates at the Landauer bound in the limit of long erasure cycles".
Claim 27 · checked 24 September 2026 · AI-assisted audit
Claim: A fifty-year-old theoretical claim about the relationship between information and thermodynamics became an experimental result.
- Kind
- Historical claim. A statement about the past that historical evidence can test.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Experimental test of Landauer’s principle in single-bit operations on nanomagnetic memory bitsIntroduction
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Review of the field
The source reads: The first direct experimental test of Landauer’s principle was reported in 2012 using a 2-μm glass bead in water manipulated in a double-well laser trap as a model system
Supports
Irreversibility and Heat Generation in the Computing Processabstract, p. 183
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: It is argued that computing machines inevitably involve devices which perform logical functions that do not have a single-valued inverse. This logical irreversibility is associated with physical irreversibility and requires a minimal heat generation, per machine cycle, typically of the order of kT for each irreversible function.
Claim 28 · checked 24 September 2026 · AI-assisted audit
Claim: Experiments since, with a particle in a feedback trap and with nanoscale magnetic bits of the kind used for data storage, have found the same floor.
- Kind
- Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
High-Precision Test of Landauer’s Principle in a Feedback Trapabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: We confirm Landauer's 1961 hypothesis that reducing the number of possible macroscopic states in a system by a factor of two requires work of at least kT ln 2. Our experiment uses a colloidal particle in a time-dependent, virtual potential created by a feedback trap
Supports
High-Precision Test of Landauer’s Principle in a Feedback Trapresults, after Table I
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: Thus, we have shown experimentally that the full-erasure protocol, which involves the compression of phase space from two macroscopic states to one, asymptotically requires kT ln 2 of work
Supports
Experimental test of Landauer’s principle in single-bit operations on nanomagnetic memory bitsabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: using nanoscale magnetic memory bits, by far the most ubiquitous digital storage technology in use today. Through sensitive, high-precision magnetometry measurements, we observed that the amount of dissipated energy in this process is consistent (within 2 SDs of experimental uncertainty) with the Landauer limit.
Supports
Experimental test of Landauer’s principle in single-bit operations on nanomagnetic memory bitsIntroduction
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: a higher precision measurement using 200-nm fluorescent particles in an electrokinetic feedback trap was recently reported
What this does not establish
Jun and others measured the work to erase rather than the heat, and reached the bound by extrapolating to slow erasure; single cycles can fall below it. Hong and others’ result is within two standard deviations of the bound.
Later work looked for
Crossref, 2017 on, "Landauer principle experimental erasure": the bound has since been tested in a feedback trap (Jun and others 2014) and in nanomagnetic bits (Hong and others 2016), both consistent with it; nothing found that overturns it. A 2026 Physical Review Letters record on shifting erasure cost below the bound with a "demon-biased" bath was seen as a title only.
Corrected
24 September 2026. Previously: “” Added so the page reports the independent tests that followed the 2012 experiment (Jun and others 2014; Hong and others 2016).
Claim 29 · checked 24 September 2026 · AI-assisted audit
Claim: Why erasing is the expensive operation
- Kind
- Framing. Signposting. It asserts nothing a source could check.
Claim: Copying a bit onto a blank one costs nothing in principle.
- Kind
- What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Notes on Landauer’s principle, reversible computation, and Maxwell’s Demonsection 1, Landauer’s Principle
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: Among the most important logically reversible operations are copying unknown data onto a blank (ie initially zero) register
Supports
Notes on Landauer’s principle, reversible computation, and Maxwell’s Demonsection 3, Landauer’s principle in the context of other ideas
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: Landauer’s principle, while perhaps obvious in retrospect, makes it clear that information processing and acquisition have no intrinsic, irreducible thermodynamic cost, whereas the seemingly humble act of information destruction does have a cost, exactly sufficient to save the Second Law from the Demon.
What this does not establish
In principle means an ideal, slow, logically reversible process; any real copy dissipates something.
Later work looked for
How the principle is stated; not a finding later work revises.
Claim 31 · checked 24 September 2026 · AI-assisted audit
Claim: Nothing is lost. The operation can be run backwards.
- Kind
- What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Notes on Landauer’s principle, reversible computation, and Maxwell’s Demonsection 1, Landauer’s Principle
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: Among the most important logically reversible operations are copying unknown data onto a blank (ie initially zero) register
What this does not establish
True of copying onto a blank register; copying over existing data is an erasure.
Later work looked for
How the principle is stated; not a finding later work revises.
Claim 32 · checked 24 September 2026 · AI-assisted audit
Claim: Erasing a bit costs at least kT ln 2 of heat.
- Kind
- What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Information and thermodynamics: experimental verification of Landauer’s erasure principlesection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Review of the field
The source reads: It states that any logically irreversible transformation of classical information is necessarily accompanied by the dissipation of at least kBT ln 2 of heat per lost bit
Supports
Irreversibility and Heat Generation in the Computing Processsection 4, p. 187
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: the number of states covered in the ensemble has been cut in half. The entropy therefore has been reduced by k loge 2 = 0.6931 k per bit ... this entropy must appear elsewhere as a heating effect, supplying 0.6931 kT per restored bit to the surroundings.
What this does not establish
For a memory in contact with a heat bath at temperature T.
Other readings
Norton and Shenker question whether heat generation must accompany logically irreversible operations at all, arguing that the entropy in the standard derivation is not thermodynamic entropy; the Stanford Encyclopedia reports the debate.
Later work looked for
How the principle is stated; not a finding later work revises.
Claim 33 · checked 24 September 2026 · AI-assisted audit
Claim: Two possible states become one. The lost distinction has to go somewhere, and it goes into the surroundings.
- Kind
- What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Irreversibility and Heat Generation in the Computing Processsection 4, p. 187
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: the number of states covered in the ensemble has been cut in half. The entropy therefore has been reduced by k loge 2 = 0.6931 k per bit ... this entropy must appear elsewhere as a heating effect, supplying 0.6931 kT per restored bit to the surroundings.
What this does not establish
What goes into the surroundings is entropy, carried as heat.
Later work looked for
How the principle is stated; not a finding later work revises.
Claim 34 · checked 24 September 2026 · AI-assisted audit
Claim: The measured heat approaches that floor as erasure slows.
- Kind
- Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Information and thermodynamics: experimental verification of Landauer’s erasure principlesection 3.2
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: The mean dissipated heat decreases with the duration of the erasure procedure τ and approaches the Landauer’s bound kBT ln 2 for long times.
Context
Experimental verification of Landauer’s principle linking information and thermodynamicsabstract
Cited · Link answered, 19 October 2026 · Abstract only, 24 September 2026 · Physical systems · Experiment
The source reads: Using a system of a single colloidal particle trapped in a modulated double-well potential, we establish that the mean dissipated heat saturates at the Landauer bound in the limit of long erasure cycles.
The Nature report of the experiment, read as its abstract only.
What this does not establish
In one colloidal-particle experiment, with the averaging described under claim 27.
Later work looked for
Crossref, 2017 on, "Landauer principle experimental erasure": the bound has since been tested in a feedback trap (Jun and others 2014) and in nanomagnetic bits (Hong and others 2016), both consistent with it; nothing found that overturns it. A 2026 Physical Review Letters record on shifting erasure cost below the bound with a "demon-biased" bath was seen as a title only.
Claim 35 · checked 24 September 2026 · AI-assisted audit
Claim: The bound is physical rather than a bookkeeping convention.
- Kind
- This page’s reading. A judgement the page makes from the evidence. Others read it differently.
- Review
- A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.
The page’s reading of the experiments: heat was measured in a physical system and matched the bound.
Supports
Information and thermodynamics: experimental verification of Landauer’s erasure principlesection 3.2
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: The mean dissipated heat decreases with the duration of the erasure procedure τ and approaches the Landauer’s bound kBT ln 2 for long times.
Other readings
Norton and Shenker question whether heat generation must accompany logically irreversible operations at all, arguing that the entropy in the standard derivation is not thermodynamic entropy; the Stanford Encyclopedia reports the debate.
Claim 36 · checked 24 September 2026 · AI-assisted audit
The usual answer to a famous demon
Claim: The usual answer to a famous demon
- Kind
- What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Information Processing and Thermodynamic Entropysection 1.3, Landauer’s principle
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: Bennett's presentation of Landauer's principle rapidly became accepted as the fundamental principle of the thermodynamics of computation.
Supports
Information and thermodynamics: experimental verification of Landauer’s erasure principlesection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026
The source reads: The paradox can be resolved by noting that during a full thermodynamic cycle, the memory of the demon, which is used to record the coordinates of each molecule, has to be reset to its initial state.
Other readings
Earman and Norton dispute that the principle is what defeats the demon; the passage reports it.
Later work looked for
Crossref, 2017 on, "Maxwell demon Landauer resolution": nothing found that displaces the account the reference work gives.
Corrected
24 September 2026. Previously: “It disposes of a famous demon” A heading under "What has been shown" said the demon was disposed of, while the passage reports that Earman and Norton deny the principle does that work and Bennett concedes the point.
Claim 37 · checked 24 September 2026 · AI-assisted audit
Claim: Maxwell imagined a being that sorts fast molecules from slow ones, creating a temperature difference without work and apparently breaking the second law.
- Kind
- Historical claim. A statement about the past that historical evidence can test.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Information Processing and Thermodynamic Entropysection 1.1, Maxwell’s demon
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: Maxwell's demon was first mentioned in a letter written to Tait in 1867.
Supports
Information Processing and Thermodynamic Entropysection 1.1, Maxwell’s demon
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: The standard demon is supposed to be able to create a temperature difference in a gas, without expending work.
Claim 38 · checked 24 September 2026 · AI-assisted audit
Claim: The standard resolution, reached by O. Penrose in 1970 and independently by Charles Bennett in 1982, is that the demon must record which molecules are which, and its memory is finite.
- Kind
- What scholars argue. A report of what specialists argue, or where they disagree.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Information Processing and Thermodynamic Entropysection 3.3, Memory and erasure
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: Penrose concluded that the demon needs to measure the location of the molecule, store that location in its memory, and can then extract the work.
Supports
Information Processing and Thermodynamic Entropysection 3.3, Memory and erasure
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: If the demon's memory is finite, eventually it will run out of space ... the demon must reset some of its memory back to zero, which requires a corresponding increase in Boltzmann entropy elsewhere. Penrose's solution was effectively rediscovered independently by Bennett (1982)
Supports
Information Processing and Thermodynamic Entropybibliography
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: Penrose, O., 1970, Foundations of Statistical Mechanics
Supports
Information and thermodynamics: experimental verification of Landauer’s erasure principlesection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026
The source reads: The paradox can be resolved by noting that during a full thermodynamic cycle, the memory of the demon, which is used to record the coordinates of each molecule, has to be reset to its initial state.
Corrected
24 September 2026. Previously: “The resolution is that the demon must record which molecules are which, and its memory is finite.” Stated flatly as "the resolution" on a question the next paragraph says is disputed; now attributed to those who gave it (Stanford Encyclopedia, section 3.3).
Claim 39 · checked 24 September 2026 · AI-assisted audit
Claim: Erasing those records costs at least as much as the sorting gained.
- Kind
- An argument. An argument a named thinker makes. That it is made is checked; whether it succeeds is argued.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Information Processing and Thermodynamic Entropysection 6, Discussion
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: this memory could not be reset without incurring an erasure cost at least equal to the work extracted.
Supports
Notes on Landauer’s principle, reversible computation, and Maxwell’s Demonsection 3, Landauer’s principle in the context of other ideas
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: Landauer’s principle, while perhaps obvious in retrospect, makes it clear that information processing and acquisition have no intrinsic, irreducible thermodynamic cost, whereas the seemingly humble act of information destruction does have a cost, exactly sufficient to save the Second Law from the Demon.
Claim 40 · checked 24 September 2026 · AI-assisted audit
Claim: On this account the second law survives because information processing is part of thermodynamics rather than outside it.
- Kind
- An argument. An argument a named thinker makes. That it is made is checked; whether it succeeds is argued.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Information Processing and Thermodynamic Entropysection 6, Discussion
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: The demon may be able to perform measurements non-dissipatively, but its memory must be representable by a physical device, and this device must be included in the statistical mechanical description.
Corrected
24 September 2026. Previously: “The second law survives because information processing is part of thermodynamics rather than outside it.” The conclusion of the Penrose and Bennett argument was stated as settled fact, directly above the objection to it.
Claim 41 · checked 24 September 2026 · AI-assisted audit
Claim: Earman and Norton, writing in 1998 and 1999, do not accept that this is what does the work.
- Kind
- What scholars argue. A report of what specialists argue, or where they disagree.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Information Processing and Thermodynamic Entropysection 3.5, Sound vs. profound dilemma
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: Earman and Norton (1999) presented a dilemma for all attempts to exorcise the Szilard engine by information theoretic arguments.
Supports
Information Processing and Thermodynamic Entropysection 3.5
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: and Norton's (1998, 1999) dilemma
Supports
Notes on Landauer’s principle, reversible computation, and Maxwell’s Demonsection 3, Landauer’s principle in the context of other ideas
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Argument
The source reads: Earman and Norton have pointed out with some justice that Landauer’s principle appears both unnecessary and insufficient as an exorcism Maxwell’s demon, because if the Demon is a thermodynamic system already governed by the Second Law, no further supposition about information and entropy is needed to save the Second Law.
Corrected
24 September 2026. Previously: “Not everyone accepts that this is what does the work.” The objection was unattributed; Bennett and the Stanford Encyclopedia both name Earman and Norton.
Claim 42 · checked 24 September 2026 · AI-assisted audit
Claim: If the demon already obeys the second law, no claim about information is needed to save the law, and if it does not, no claim about information will.
- Kind
- An argument. An argument a named thinker makes. That it is made is checked; whether it succeeds is argued.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Notes on Landauer’s principle, reversible computation, and Maxwell’s Demonsection 3, Landauer’s principle in the context of other ideas
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Argument
The source reads: Earman and Norton have pointed out with some justice that Landauer’s principle appears both unnecessary and insufficient as an exorcism Maxwell’s demon, because if the Demon is a thermodynamic system already governed by the Second Law, no further supposition about information and entropy is needed to save the Second Law.
Supports
Notes on Landauer’s principle, reversible computation, and Maxwell’s Demonsection 3, Landauer’s principle in the context of other ideas
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Argument
The source reads: On the other hand, if the Demon is not assumed to obey the Second Law, no supposition about the entropy cost of information processing can save the Second Law from the Demon.
Claim 43 · checked 24 September 2026 · AI-assisted audit
Claim: Bennett grants the point, and defends the principle for what it explains.
- Kind
- What scholars argue. A report of what specialists argue, or where they disagree.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Notes on Landauer’s principle, reversible computation, and Maxwell’s Demonsection 3, Landauer’s principle in the context of other ideas
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Argument
The source reads: Earman and Norton have pointed out with some justice that Landauer’s principle appears both unnecessary and insufficient as an exorcism Maxwell’s demon, because if the Demon is a thermodynamic system already governed by the Second Law, no further supposition about information and entropy is needed to save the Second Law.
Supports
Notes on Landauer’s principle, reversible computation, and Maxwell’s Demonsection 3, Landauer’s principle in the context of other ideas
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026
The source reads: I would nevertheless argue that Landauer’s principle serves an important pedagogic purpose
Corrected
24 September 2026. Previously: “” Added so the dispute is reported with both sides: the principle’s leading defender concedes the objection "with some justice".
Claim 44 · checked 24 September 2026 · AI-assisted audit
What is claimed beyond it
Claim: What is claimed beyond it
- Kind
- Framing. Signposting. It asserts nothing a source could check.
Claim: The demon fails not because it cannot sort, but because it has to remember.
- Kind
- This page’s reading. A judgement the page makes from the evidence. Others read it differently.
- Review
- A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.
A compression of the Penrose and Bennett resolution: a finite memory must eventually be reset, and the reset is what costs.
Supports
Information Processing and Thermodynamic Entropysection 3.3, Memory and erasure
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: If the demon's memory is finite, eventually it will run out of space ... the demon must reset some of its memory back to zero, which requires a corresponding increase in Boltzmann entropy elsewhere. Penrose's solution was effectively rediscovered independently by Bennett (1982)
Other readings
Earman and Norton argue that this is not what defeats the demon; see claim 42.
Claim 46 · checked 24 September 2026 · AI-assisted audit
How far the identification goes
Claim: How far the identification goes
- Kind
- Framing. Signposting. It asserts nothing a source could check.
Claim: That erasure has a thermodynamic cost is widely accepted
- Kind
- What the field holds. The settled view of a field, as a review, a consensus statement or a reference work gives it. Not one study.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Information Processing and Thermodynamic Entropysection 1.3, Landauer’s principle
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: Bennett's presentation of Landauer's principle rapidly became accepted as the fundamental principle of the thermodynamics of computation.
Qualifies
Information Processing and Thermodynamic Entropysection 4
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Reference work
The source reads: focussed upon whether heat generation must necessarily be associated with logically irreversible operations ... Norton argued in detail that this is an illegitimate calculation, and that the resulting entropy has nothing to do with thermodynamic entropy.
Other readings
Norton and Shenker question whether heat generation must accompany logically irreversible operations at all, arguing that the entropy in the standard derivation is not thermodynamic entropy; the Stanford Encyclopedia reports the debate.
Later work looked for
Crossref, 2017 on, "Landauer principle experimental erasure": the bound has since been tested in a feedback trap (Jun and others 2014) and in nanomagnetic bits (Hong and others 2016), both consistent with it; nothing found that overturns it. A 2026 Physical Review Letters record on shifting erasure cost below the bound with a "demon-biased" bath was seen as a title only.
Corrected
24 September 2026. Previously: “That erasure has a thermodynamic cost is established.” "Established" passed over the critics the Stanford Encyclopedia reports (Shenker, Norton); what the sources carry is wide acceptance and measurement.
Claim 48 · checked 24 September 2026 · AI-assisted audit
Claim: and has been measured.
- Kind
- Experimental result. What an experiment or trial found, under its own conditions. A result in animals, cells or a simulation is not a result in people.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Information and thermodynamics: experimental verification of Landauer’s erasure principlesection 3.2
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: The mean dissipated heat decreases with the duration of the erasure procedure τ and approaches the Landauer’s bound kBT ln 2 for long times.
Supports
Experimental test of Landauer’s principle in single-bit operations on nanomagnetic memory bitsabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Physical systems · Experiment
The source reads: using nanoscale magnetic memory bits, by far the most ubiquitous digital storage technology in use today. Through sensitive, high-precision magnetometry measurements, we observed that the amount of dissipated energy in this process is consistent (within 2 SDs of experimental uncertainty) with the Landauer limit.
What this does not establish
In small laboratory systems: a colloidal bead and nanomagnets.
Later work looked for
Crossref, 2017 on, "Landauer principle experimental erasure": the bound has since been tested in a feedback trap (Jun and others 2014) and in nanomagnetic bits (Hong and others 2016), both consistent with it; nothing found that overturns it. A 2026 Physical Review Letters record on shifting erasure cost below the bound with a "demon-biased" bath was seen as a title only.
Claim 49 · checked 24 September 2026 · AI-assisted audit
Claim: That the universe is in some deeper sense made of information is a much stronger claim, and it is a research programme rather than a result.
- Kind
- This page’s reading. A judgement the page makes from the evidence. Others read it differently.
- Review
- A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.
The page’s judgement: nothing in the erasure experiments bears on what the universe is made of, and the nearest concrete work is an argued programme, as claim 52 describes.
Supports
Building up spacetime with quantum entanglementabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: we argue that the emergence of classically connected spacetimes is intimately related to the quantum entanglement of degrees of freedom in a non-perturbative description of quantum gravity.
Claim 50 · checked 24 September 2026 · AI-assisted audit
Claim: Ideas connecting entanglement to the structure of spacetime are among the more concrete versions
- Kind
- This page’s reading. A judgement the page makes from the evidence. Others read it differently.
- Review
- A judgement, not a fact. Reviewed for whether it is fairly put and follows from the checked claims. No source can confirm it.
Van Raamsdonk argues that connected spacetime emerges from quantum entanglement; calling that a version of the information claim is the page’s reading.
Supports
Building up spacetime with quantum entanglementabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Argument
The source reads: we argue that the emergence of classically connected spacetimes is intimately related to the quantum entanglement of degrees of freedom in a non-perturbative description of quantum gravity.
Claim 51 · checked 24 September 2026 · AI-assisted audit
Claim: and they are mathematical relationships in particular model spacetimes rather than statements about this one.
- Kind
- What a model says. What a theory or model predicts or describes, which is not the same as what has been observed.
- Review
- Source checked. The cited passage was read, and it says this.
Supports
Building up spacetime with quantum entanglementIntroduction
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model
The source reads: It posits that certain quantum gravitational theories with fixed spacetime asymptotic behavior are exactly equivalent to ordinary quantum field theories.
Supports
Building up spacetime with quantum entanglementsection Classical connectivity from quantum superposition
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model
The source reads: The most familiar example of gauge-theory / gravity duality involves an equivalence between conformal field theories (CFTs) and asymptotically anti-de Sitter (AdS) spacetimes.
What this does not establish
The essay argues inside gauge-gravity duality, for spacetimes with anti-de Sitter asymptotics; it does not claim the result for the observed universe.
Later work looked for
Model claim; later holography work extends the programme but is not read here.
Claim 52 · checked 24 September 2026 · AI-assisted audit
What was read
- Experimental verification of Landauer’s principle linking information and thermodynamicsBerut and others, Nature · Nature 483, 187-189, abstract through Europe PMC (PMID 22398556)Abstract only, 24 September 2026 · Copyright; quoted briefly
- Irreversibility and Heat Generation in the Computing ProcessLandauer, IBM Journal of Research and Development · IBM Journal of Research and Development 5(3), July 1961, pp. 183-191; scanned original with an OCR text layer, hosted at informationphilosopher.comRead in full, 24 September 2026 · Copyright IBM; quoted brieflyThe OCR splits words with soft hyphens at line ends; the cached text rejoins them. It reads "question;" where the print has a colon, so the excerpt skips that mark.
- Information and thermodynamics: experimental verification of Landauer’s erasure principleBerut, Petrosyan and Ciliberto, Journal of Statistical Mechanics · arXiv:1503.06537v1 (23 March 2015)Read in full, 24 September 2026 · Copyright; quoted briefly
- Notes on Landauer’s principle, reversible computation, and Maxwell’s DemonBennett, Studies in History and Philosophy of Modern Physics · arXiv:physics/0210005v2 (9 January 2003)Read in full, 24 September 2026 · Copyright; quoted briefly
- High-Precision Test of Landauer’s Principle in a Feedback TrapJun, Gavrilov and Bechhoefer, Physical Review Letters · arXiv:1408.5089v1 (16 August 2014), read as a PDF in full; published as Physical Review Letters 113, 190601Read in full, 24 September 2026 · Copyright; quoted briefly
- Experimental test of Landauer’s principle in single-bit operations on nanomagnetic memory bitsHong, Lambson, Dhuey and Bokor, Science Advances · Science Advances 2(3), e1501492, full text through Europe PMC (PMC4795654)Read in full, 24 September 2026 · CC BY-NC 4.0
- Information Processing and Thermodynamic EntropyMaroney, Stanford Encyclopedia of Philosophy · Stanford Encyclopedia of Philosophy, entry first published 15 September 2009, as served on the access dateRead in full, 24 September 2026 · Copyright; quoted briefly
- Building up spacetime with quantum entanglementVan Raamsdonk, General Relativity and Gravitation · arXiv:1005.3035v2, read from the TeX sourceRead in full, 24 September 2026 · Copyright; quoted briefly