Evidence record

Could this be a simulation?

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.

A judgement, not a fact: 9
Source checked: 42
Presented as open: 1

If something here is wrong, misquoted, out of date or unfair, write to support@unknownoceans.com and give the claim number, which does not change.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 philosophical argument with empirical premises. What the argument says can be checked against its text; whether it succeeds cannot, and the page reports the published objections and the replies to them rather than a verdict. Whether we are simulated is open, and no proposed test reaches it in general.

A simulation of a mind, detailed enough, would have experiences
Contested
Bostrom calls this substrate-independence and takes it as given. The survey of the science of consciousness the page cites adopts the related view only as a working hypothesis and names researchers who reject it.
A technologically mature civilisation would have the computing power to run vast numbers of such simulations
Contested
The paper supports it with estimates for designs that have not been built. A 2025 calculation disputes that any universe with our physics could supply the energy; Bostrom replies that the calculation assumes a far more complete simulation than the argument needs.
Your credence that you are simulated should equal the fraction of observers like you who are
Contested
Bostrom’s bland indifference principle. Weatherson and Birch argue it cannot carry the conclusion as used; Bostrom replied to Weatherson.
Whether we are simulated would leave a trace anyone could find
Open
One proposal tests one way a simulation might be built. Bostrom holds that evidence bearing on the other two branches bears on the third, and doubts any simple experiment would settle it.

How the question is labelled

Claim: The argument, and what it is not

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 title. It follows from the paper’s own statement that it establishes a disjunction (claims 13 and 20).

Claim 1 · checked 24 September 2026 · AI-assisted audit

Claim: Simulation

Kind: Framing. Signposting. It asserts nothing a source could check.

The question

Claim: The well-known argument does not claim we are in one.

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.

The author also says he would give the hypothesis that we are simulated a “substantial probability”, which is his credence and not something the argument shows.

Supports
The Simulation Argument FAQquestion 2
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: The argument shows only that at least one of three possibilities obtains, but it does not tell us which one(s). One could accept the simulation argument while rejecting the simulation hypothesis (i.e. that we are in a simulation).

Claim 3 · checked 24 September 2026 · AI-assisted audit

Claim: It claims that at least one of three things must be true

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
Are We Living in a Computer Simulation?abstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: This paper argues that at least one of the following propositions is true

Corrected

24 September 2026. Previously: “It claims that one of three things must be true” The paper says “at least one”. More than one branch can hold at once, and “one of three” reads as exactly one.

Claim 4 · checked 24 September 2026 · AI-assisted audit

Claim: and that is a weaker and more interesting statement.

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. A disjunction is weaker than any one of its branches, which is logic rather than a finding.

Claim 5 · checked 24 September 2026 · AI-assisted audit

Claim: A 2003 paper by Nick Bostrom argues that at least one of three propositions holds: civilisations almost never reach the ability to run ancestor simulations, almost none that can do so choose to, or almost everyone with our kind of experience is simulated.

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.

A “posthuman” stage, in the paper, is one with the computing power to run such simulations, so the first branch is phrased here as never reaching that ability.

Supports
Are We Living in a Computer Simulation?section VII
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: (1) The fraction of human-level civilizations that reach a posthuman stage is very close to zero; (2) The fraction of posthuman civilizations that are interested in running ancestor-simulations is very close to zero; (3) The fraction of all people with our kind of experiences
Supports
Are We Living in a Computer Simulation?section VII; section III, closing summary
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: (3) The fraction of all people with our kind of experiences that are living in a simulation is very close to one. ... Posthuman civilizations would have enough computing power to run hugely many ancestor-simulations even while using only a tiny fraction of their resources for that purpose.

Corrected

24 September 2026. Previously: “A 2003 paper argues” The page later reports Bostrom’s replies to objections by name, so the author is named where the paper is first mentioned.

Claim 6 · checked 24 September 2026 · AI-assisted audit

Claim: It is a disjunction

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
The Simulation Argument FAQquestion 3
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: to argue that we have interesting empirical reasons to believe that a certain disjunctive claim about the world is true

Claim 7 · checked 24 September 2026 · AI-assisted audit

Claim: it rests on assumptions that have been questioned in print

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
Are You a Sim?abstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Argument
The source reads: The argument appeals crucially to an indifference principle whose precise content is a little unclear.
Supports
On the ‘Simulation Argument’ and Selective Scepticismabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Argument
The source reads: I first show that the Simulation Argument requires a curious form of selective scepticism

Corrected

24 September 2026. Previously: “it rests on assumptions that can be questioned” The objections are published, and the page now names two of them (claims 41 and 43).

Claim 8 · checked 24 September 2026 · AI-assisted audit

Claim: and its author doubts that any simple experiment could show which branch is true.

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
The Simulation Argument FAQquestion 11
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: One might wonder whether there is any kind of test that we could conduct in the near term that would definitely reveal which of the three disjuncts is true. I doubt that there is any simple experiment

Corrected

24 September 2026. Previously: “and it has no known test.” Tests have been proposed for particular ways a simulation might be built (claim 46), and Bostrom holds that evidence bearing on the branches is possible. What he doubts is a simple experiment that settles which branch holds.

Claim 9 · checked 24 September 2026 · AI-assisted audit

Claim: The argument caught the public imagination

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
On the ‘Simulation Argument’ and Selective Scepticismsection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Argument
The source reads: This remarkable argument has, perhaps more than any other in recent philosophy, ... caught the public imagination, spawning numerous popularizations

Claim 10 · checked 24 September 2026 · AI-assisted audit

Claim: and it is easy to retell as proof that we are probably in a simulation.

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 how the argument travels. No survey of retellings was read; the claim is about how easily the third branch can be detached from the other two.

Corrected

24 September 2026. Previously: “The version that circulates is that a philosopher proved we are probably in a simulation.” What “circulates” is a factual claim about popular retellings that no source read could carry. The page now says what a source does carry, that the argument reached a wide public, and gives the rest as its own reading.

Claim 11 · checked 24 September 2026 · AI-assisted audit

Claim: That is not what the paper says.

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
Are We Living in a Computer Simulation?section VII
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: In the dark forest of our current ignorance, it seems sensible to apportion one’s credence roughly evenly between (1), (2), and (3).

Claim 12 · checked 24 September 2026 · AI-assisted audit

Claim: What it argues is that three possibilities cannot all be false at once

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
Are We Living in a Computer Simulation?section IV
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: at least one of the following three propositions must be true

Claim 13 · checked 24 September 2026 · AI-assisted audit

Claim: which leaves the conclusion up to which of them you find least unlikely.

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 what a disjunction leaves to the reader.

Other readings

The paper’s own suggestion is an even split between the three (claim 21), and its author notes that people who accept the argument tend to find a different branch obvious.

Claim 14 · checked 24 September 2026 · AI-assisted audit

What the argument says

Claim: What the argument says

Kind: Framing. Signposting. It asserts nothing a source could check.

The structure of the argument

Claim: The structure of the argument

Kind: Framing. Signposting. It asserts nothing a source could check.

Claim: If a civilisation reaches the capacity to run simulations of its own history containing conscious inhabitants, and if a reasonable fraction choose to run many, then simulated experiences of a kind like ours vastly outnumber unsimulated ones.

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
Are We Living in a Computer Simulation?section I
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: Because their computers would be so powerful, they could run a great many such simulations. Suppose that these simulated people are conscious ... Then it could be the case that the vast majority of minds like ours do not belong to the original race

Claim 17 · checked 24 September 2026 · AI-assisted audit

Claim: Given that, and given no way to tell from inside which kind you are having, the reasonable estimate of being simulated is high.

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.

The paper calls this step a bland indifference principle: your credence that you are simulated should equal the fraction of such observers who are.

Supports
Are We Living in a Computer Simulation?section V
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: if we knew that a fraction x of all observers with human-type experiences live in simulations, and we don’t have any information that indicate that our own particular experiences are any more or less likely than other human-type experiences

What this does not establish

This is the step Weatherson and Birch dispute (claims 41 and 43). The paper defends it only briefly and refers to a book for the full defence.

Claim 18 · checked 24 September 2026 · AI-assisted audit

Claim: So either the first condition fails, or the second fails, or the conclusion holds.

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
Are We Living in a Computer Simulation?section IV
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: at least one of the following three propositions must be true

Claim 19 · checked 24 September 2026 · AI-assisted audit

Claim: The paper is careful that this is a disjunction and that it does not establish which branch is true.

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
Are We Living in a Computer Simulation?section I
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: Lastly, we discuss some interpretations of the disjunction, mentioned in the abstract, that forms the conclusion of the simulation argument.
Supports
The Simulation Argument FAQquestion 2
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: The argument shows only that at least one of three possibilities obtains, but it does not tell us which one(s).

Claim 20 · checked 24 September 2026 · AI-assisted audit

Claim: Its own suggestion, in “the dark forest of our current ignorance”, is to spread belief roughly evenly across the three.

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.

In the later FAQ Bostrom declines to give a number, and says each branch deserves some non-negligible probability.

Supports
Are We Living in a Computer Simulation?section VII
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: In the dark forest of our current ignorance, it seems sensible to apportion one’s credence roughly evenly between (1), (2), and (3).

Corrected

24 September 2026. Previously: “” The paper does say how it would weigh the branches, and that is the plainest answer to the popular version the page opens with.

Claim 21 · checked 24 September 2026 · AI-assisted audit

Claim: The three branches

Kind: Framing. Signposting. It asserts nothing a source could check.

Claim: Almost no civilisation gets there

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
Are We Living in a Computer Simulation?section VII
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: (1) The fraction of human-level civilizations that reach a posthuman stage is very close to zero

Claim 23 · checked 24 September 2026 · AI-assisted audit

Claim: Something reliably stops technological civilisations before they can simulate minds.

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.

The paper names extinction and the collapse of technological civilisation as ways this branch could hold.

Supports
Are We Living in a Computer Simulation?section VI
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: If (1) is true, then humankind will almost certainly fail to reach a posthuman level; for virtually no species at our level of development become posthuman

Claim 24 · checked 24 September 2026 · AI-assisted audit

Claim: That is a claim about our own future as much as anyone else’s.

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
Are We Living in a Computer Simulation?section VI
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: it is hard to see any justification for thinking that our own species will be especially privileged or protected from future disasters

Claim 25 · checked 24 September 2026 · AI-assisted audit

Claim: Almost none that can, do

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
Are We Living in a Computer Simulation?section VII
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: (2) The fraction of posthuman civilizations that are interested in running ancestor-simulations is very close to zero

Claim 26 · checked 24 September 2026 · AI-assisted audit

Claim: The capability is reached and essentially never used at scale.

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
Are We Living in a Computer Simulation?section VI
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: Virtually no posthuman civilizations decide to use their resources to run large numbers of ancestor-simulations.

Claim 27 · checked 24 September 2026 · AI-assisted audit

Claim: That requires a strong convergence among advanced civilisations, in what their members want or in laws that stop them.

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
Are We Living in a Computer Simulation?section VI
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: In order for (2) to be true, there must be a strong convergence among the courses of advanced civilizations.
Supports
Are We Living in a Computer Simulation?section VI
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: Furthermore, virtually all posthuman civilizations lack ... individuals who have sufficient resources and interest to run ancestor-simulations; or else they have reliably enforced laws that prevent such individuals from acting on their desires.

Corrected

24 September 2026. Previously: “The capability is reached and essentially never used at scale, which requires a convergence of motives across every civilisation.” The paper allows the convergence to be in enforced prohibitions as well as in motives, and it speaks of virtually all civilisations rather than every one.

Claim 28 · checked 24 September 2026 · AI-assisted audit

Claim: Almost everyone like us is simulated

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
Are We Living in a Computer Simulation?section VII
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: (3) The fraction of all people with our kind of experiences that are living in a simulation is very close to one.

Claim 29 · checked 24 September 2026 · AI-assisted audit

Claim: The simulations vastly outnumber the originals, and there is no way to tell from inside.

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
Are We Living in a Computer Simulation?section V
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: assuming only that we have no information that enables us to predict any differences between the experiences of simulated minds and those of the original biological minds

What this does not establish

“No way to tell” is a condition the argument assumes, not something it shows. The paper supports it by supposing simulators could edit away any anomaly a simulated observer noticed.

Claim 30 · checked 24 September 2026 · AI-assisted audit

What it assumes

Claim: What it assumes

Kind: Framing. Signposting. It asserts nothing a source could check.

Where it can be resisted

Claim: Where it can be resisted

Kind: Framing. Signposting. It asserts nothing a source could check.

Claim: The argument assumes that a simulation of a mind would have experiences, and the paper takes this as given.

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.

The paper needs only a weak form: that a brain’s computations replicated in fine enough detail, such as individual synapses, would produce experience.

Supports
Are We Living in a Computer Simulation?section II
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: Provided a system implements the right sort of computational structures and processes, it can be associated with conscious experiences.
Supports
Are We Living in a Computer Simulation?section II
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: although it is not entirely uncontroversial, we shall here take it as a given

Corrected

24 September 2026. Previously: “The argument assumes that a simulation of a mind would have experiences, which is exactly the question about machine consciousness that nobody can answer.” “Nobody can answer” claimed more than the cited survey says. It treats the question as open and investigable, adopts computational functionalism as a working hypothesis and names researchers who reject it. The paper’s own stance, that it takes the assumption as given, is now stated.

Claim 33 · checked 24 September 2026 · AI-assisted audit

Claim: It is the unsettled question of machine consciousness: a 2023 survey of the science adopts the view behind it only as a working hypothesis, and names researchers who reject it.

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.

The survey’s working hypothesis is computational functionalism, that implementing the right computations is necessary and sufficient for consciousness. Bostrom’s substrate-independence asks only for the sufficient half.

Supports
Consciousness in Artificial Intelligence: Insights from the Science of Consciousnesssection 1.2
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Review of the field
The source reads: We adopt computational functionalism as a working hypothesis because this assumption makes it relatively straightforward to draw
Supports
Consciousness in Artificial Intelligence: Insights from the Science of Consciousnesssection 1.2
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Review of the field
The source reads: Some researchers in this area reject computational functionalism (e.g. Searle 1980, Tononi & Koch 2015)

What this does not establish

The survey is about AI systems rather than simulated brains, and its authors say they hold different levels of confidence in the hypothesis.

Later work looked for

Crossref, 2023 on, “identifying indicators of consciousness in AI systems Butlin”: the same group’s “Identifying indicators of consciousness in AI systems” (Trends in Cognitive Sciences, 2026 issue) and an encyclopedia entry by Butlin (2026) were found by title and not read; nothing in the records suggests the question is settled.

Claim 34 · checked 24 September 2026 · AI-assisted audit

Claim: It also relies on a principle for reasoning when you do not know which of many observers you are

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
Are We Living in a Computer Simulation?section V
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: the bland indifference principle expressed by (#) prescribes indifference only between hypotheses about which observer you are, when you have no information about which of these observers you are

Corrected

24 September 2026. Previously: “It also uses a principle about reasoning from one’s own observations that is contested, and it assumes computational resources adequate to simulate minds at scale, which is a physical claim nobody can currently evaluate.” The principle is about which observer you are, not about reasoning from observations. And the computing claim is one the paper does evaluate, with estimates, and one a 2025 calculation disputes: “nobody can currently evaluate” was wrong on both counts.

Claim 35 · checked 24 September 2026 · AI-assisted audit

Claim: and that principle has been contested.

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
Are You a Sim?abstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Argument
The source reads: I set out five possible interpretations of the principle, none of which can be used to support Bostrom’s argument.
Supports
On the ‘Simulation Argument’ and Selective Scepticismsection 1
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Argument
The source reads: Bostrom now takes a bold ‘further step’.

Claim 36 · checked 24 September 2026 · AI-assisted audit

Claim: And it assumes that computers able to simulate minds at scale are physically possible, which the paper supports with estimates for designs nobody has built.

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
Are We Living in a Computer Simulation?section III
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: At our current stage of technological development, we have neither sufficiently powerful hardware nor the requisite software to create conscious minds in computers.
Supports
Are We Living in a Computer Simulation?section III
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: We can with much greater confidence establish lower bounds on posthuman computation, by assuming only mechanisms that are already understood. For example, Eric Drexler has outlined a design for a system the size of a sugar cube

Claim 37 · checked 24 September 2026 · AI-assisted audit

Claim: A 2025 calculation by Franco Vazza finds that no universe with physics like ours could supply the energy, even for a low-resolution simulation of Earth alone

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
Astrophysical constraints on the simulation hypothesis for this Universe: why it is (nearly) impossible that we live in a simulationabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model
The source reads: In all cases, the amounts of energy or power required by any version of the simulation hypothesis are entirely incompatible with physics or (literally) astronomically large, even in the lowest resolution case.
Supports
Astrophysical constraints on the simulation hypothesis for this Universe: why it is (nearly) impossible that we live in a simulationabstract, Methods
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model
The source reads: We investigate three cases: the simulation of the entire visible Universe, the simulation of Earth only, or a low-resolution simulation of Earth compatible with high-energy neutrino observations.
Supports
Astrophysical constraints on the simulation hypothesis for this Universe: why it is (nearly) impossible that we live in a simulationabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model
The source reads: It is simply impossible for this Universe to be simulated by a universe sharing the same properties
Supports
Astrophysical constraints on the simulation hypothesis for this Universe: why it is (nearly) impossible that we live in a simulationsection 3.3
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model
The source reads: an additional speed-up of order × 10¹⁵ − 10¹⁷ (or larger) would be necessary to advance the low-resolution simulation of Earth faster than real time
Notation restored: Superscripts restored from the publisher’s full-text HTML (MathML), read 2026-09-24. The text as extracted reads: an additional speed-up of order × 1015 − 1017 (or larger) would be necessary to advance the low-resolution simulation of Earth faster than real time
Supports
Astrophysical constraints on the simulation hypothesis for this Universe: why it is (nearly) impossible that we live in a simulationsection 3.3
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model
The source reads: In this case, the necessary computing power will be simply impossible to collect
Supports
Astrophysical constraints on the simulation hypothesis for this Universe: why it is (nearly) impossible that we live in a simulationsection 5
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model
The source reads: all plausible approaches tested in this work (in order to reproduce at least a fraction of the reality we humans experience) require access to impossibly large amounts of energy or computing power
Qualifies
Astrophysical constraints on the simulation hypothesis for this Universe: why it is (nearly) impossible that we live in a simulationsection 4.2
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model
The source reads: This power is astronomically large but not entirely impossible
Only if high-energy neutrinos could be propagated with a far coarser time step than the one the paper derives from observations.

What this does not establish

It is one author’s estimate, and it bounds a simulator whose physics matches ours, which the paper does not assume. The paper’s own discussion finds the power “astronomically large but not entirely impossible” if the simulation could skip the fine time step that observed neutrinos require.

Other readings

Bostrom holds that the calculation assumes a far more complete simulation than the argument needs (claim 39).

Later work looked for

Crossref, 2025 on, the paper’s title: a 2026 commentary on it in the same journal (Edge and Brown) was found, with no abstract in the record; not read.

Corrected

24 September 2026. Previously: “” The computing premise is contested in print. The rival calculation and the reply are both reported, with who holds each side.

Claim 38 · checked 24 September 2026 · AI-assisted audit

Claim: Bostrom replies that it assumes a far more complete simulation than the argument needs.

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
The Simulation Argument FAQquestion 6
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: Critiques based on the assumption that a simulation would have to be fully comprehensive (e.g. Vazza (2025)) thus miss the point.
Context
Are We Living in a Computer Simulation?section III
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: Simulating the entire universe down to the quantum level is obviously infeasible, unless radically new physics is discovered.

Claim 39 · checked 24 September 2026 · AI-assisted audit

Claim: Whether any of these objections is decisive is itself disputed.

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
On the ‘Simulation Argument’ and Selective Scepticismabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Argument
The source reads: There is thus no good reason to believe its conclusion.
Supports
The Simulation Argument FAQquestion 2
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: I believe that the simulation argument is basically sound.

Corrected

24 September 2026. Previously: “None of these objections is decisive.” Weatherson and Birch each argue that their objection defeats the argument as stated, and Bostrom holds it sound. The page reported one side of a published disagreement as settled.

Claim 40 · checked 24 September 2026 · AI-assisted audit

Claim: Brian Weatherson argued in 2003 that none of five ways of reading the principle will carry the conclusion

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
Are You a Sim?abstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Argument
The source reads: I set out five possible interpretations of the principle, none of which can be used to support Bostrom’s argument.

Corrected

24 September 2026. Previously: “” Names who holds each side of the disagreement over the principle.

Claim 41 · checked 24 September 2026 · AI-assisted audit

Claim: and Bostrom replied in 2005.

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
The Simulation Argument: Reply to Weathersonp. 90, abstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: I reply to some recent comments by Brian Weatherson on my ‘simulation argument’.

Claim 42 · checked 24 September 2026 · AI-assisted audit

Claim: Jonathan Birch argued in 2013 that the argument trusts our evidence about the limits of computing while doubting our evidence about our own physical make-up.

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.

Published online in 2012 and in the 2013 volume of Erkenntnis.

Supports
On the ‘Simulation Argument’ and Selective Scepticismabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Argument
The source reads: it presupposes that we possess good evidence for claims about the physical limits of computation and yet lack good evidence for claims about our own physical constitution

Corrected

24 September 2026. Previously: “” A published objection to the argument, reported with who holds it.

Claim 43 · checked 24 September 2026 · AI-assisted audit

Claim: Each is a place where the argument requires something it does not establish.

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. The paper takes substrate-independence as given, supports the computing premise with estimates, and defends its principle briefly, referring to a book for the rest.

Other readings

Bostrom holds that the premises are adequately supported and the argument basically sound (claim 40).

Claim 44 · checked 24 September 2026 · AI-assisted audit

Whether anything would show

Claim: Whether anything would show

Kind: Framing. Signposting. It asserts nothing a source could check.

Claim: One proposal for detecting a simulation looks for artefacts of discretisation.

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
Constraints on the universe as a numerical simulationabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model
The source reads: Observable consequences of the hypothesis that the observed universe is a numerical simulation performed on a cubic space-time lattice or grid are explored.
Context
The Simulation Argument FAQquestion 12
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: Another example of a proposed physics test derives from the Ringel & Kovrizhin (2017) attempt to show that classical computers cannot efficiently simulate certain quantum systems
Not every proposed test looks for discretisation.

Corrected

24 September 2026. Previously: “Proposals for detecting a simulation look for artefacts of discretisation. The worked one assumes” Not all proposals look for discretisation: others turn on whether classical computers can efficiently simulate certain quantum systems. The page describes the one it cites.

Claim 46 · checked 24 September 2026 · AI-assisted audit

Claim: It assumes our universe is being run with the lattice methods physicists already use on their own simulations, and uses the high-energy cutoff of the cosmic ray spectrum to bound how coarse that lattice could be.

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
Constraints on the universe as a numerical simulationabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model
The source reads: Using the historical development of lattice gauge theory technology as a guide, we assume that our universe is an early numerical simulation with unimproved Wilson fermion discretization
Supports
Constraints on the universe as a numerical simulationabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model
The source reads: the most stringent bound on the inverse lattice spacing of the universe ... is derived from the high-energy cut off of the cosmic ray spectrum

What this does not establish

The assumption is the cheapest, unimproved form of those methods, chosen as a starting point. The bound holds only if the universe is such a lattice.

Claim 47 · checked 24 September 2026 · AI-assisted audit

Claim: What it says to look for is not the cutoff.

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
Constraints on the universe as a numerical simulationabstract
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model
The source reads: The numerical simulation scenario could reveal itself in the distributions of the highest energy cosmic rays exhibiting a degree of rotational symmetry breaking

What this does not establish

The cutoff constrains the lattice spacing; it is not the proposed signature.

Claim 48 · checked 24 September 2026 · AI-assisted audit

Claim: It is a direction: the highest-energy cosmic rays arriving with their rotational symmetry broken along the axes of the grid underneath.

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
Constraints on the universe as a numerical simulationsection IV
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model
The source reads: the angular distribution of the highest energy components would exhibit cubic symmetry in the rest frame of the lattice, deviating significantly from isotropy

What this does not establish

A prediction under the model, not an observation. The paper says the pattern is strongest where the lattice itself sets the cutoff and fades for finer lattices.

Later work looked for

Crossref, 2014 on, “simulation hypothesis cosmic rays lattice”: no reported search for this signature was found.

Claim 49 · checked 24 September 2026 · AI-assisted audit

Claim: That tests a particular implementation rather than the hypothesis

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
Constraints on the universe as a numerical simulationsection I
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model
The source reads: we focus on one aspect only: the possibility that the simulations of the future employ an underlying cubic lattice structure

Claim 50 · checked 24 September 2026 · AI-assisted audit

Claim: and its authors note that the improved methods lattice physicists already use would mask much of what it looks for.

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
Constraints on the universe as a numerical simulationsection V
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Theory · Model
The source reads: Given the ease with which current lattice QCD simulations incorporate improvement or employ discretizations that preserve chiral symmetry ... Of course, improvement in this context masks much of our ability to probe the possibility that our universe is a simulation

Corrected

24 September 2026. Previously: “That tests a particular implementation rather than the hypothesis.” The proposal’s own authors say this, and it is the strongest limit on the test.

Claim 51 · checked 24 September 2026 · AI-assisted audit

Claim: A simulation built to keep its own physics consistent leaves nothing of that kind to find.

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, which Bostrom shares.

Context
The Simulation Argument FAQquestion 12
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: the simulators could fake the results in ways that at our current levels of capability we would be unable to detect

Other readings

Beane, Davoudi and Savage hold that a simulator with finite resources must use a lattice spacing above zero, so that in principle the simulated can always discover the simulators.

Corrected

24 September 2026. Previously: “A simulation designed to be consistent with its own physics leaves nothing to find, which makes the claim unfalsifiable in the general case.” “Unfalsifiable” is disputed by the argument’s author, who holds that evidence about the first two branches bears on the third. The page now reports his view instead of asserting the opposite.

Claim 52 · checked 24 September 2026 · AI-assisted audit

Claim: Bostrom still rejects the charge that the hypothesis is unfalsifiable

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
The Simulation Argument FAQquestion 11
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: So the simulation hypothesis is clearly empirically testable in the sense that there are possible observations we might make that would either increase or decrease the probability that it is true.

Claim 53 · checked 24 September 2026 · AI-assisted audit

Claim: evidence that makes either of the first two branches less likely makes the third more likely, which is evidence, though not an experiment.

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
The Simulation Argument FAQquestion 11
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: Consequently, evidence that makes the first two propositions less likely would make the third proposition more likely
Supports
The Simulation Argument FAQquestion 11
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: I doubt that there is any simple experiment

What this does not establish

Evidence of this kind moves the balance between the branches; it does not reach whatever might be running a simulation.

Claim 54 · checked 24 September 2026 · AI-assisted audit

What would follow

Claim: What would follow

Kind: Framing. Signposting. It asserts nothing a source could check.

Claim: A disjunction, not a verdict

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
The Simulation Argument FAQquestion 2
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: The argument shows only that at least one of three possibilities obtains, but it does not tell us which one(s).

Corrected

24 September 2026. Previously: “A disjunction, not a conclusion” The paper calls the disjunction its conclusion. What it does not give is a verdict on which branch holds.

Claim 56 · checked 24 September 2026 · AI-assisted audit

Claim: and the popular version keeps only the third branch.

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, following claim 11.

Claim 57 · checked 24 September 2026 · AI-assisted audit

Whether the question changes anything

Claim: Whether the question changes anything

Kind: Framing. Signposting. It asserts nothing a source could check.

Claim: If the simulation is consistent, everything inside it behaves exactly as physics describes, and every measurement anyone makes comes out the same.

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. It follows from what “consistent” means here, and the paper draws a similar conclusion for how we should go on.

Context
Are We Living in a Computer Simulation?section VI
Cited · Link answered, 19 October 2026 · Read in full, 24 September 2026 · Primary text
The source reads: Our best guide to how our posthuman creators have chosen to set up our world is the standard empirical study of the universe we see.

Claim 59 · checked 24 September 2026 · AI-assisted audit

Claim: That is the honest reason this question sits so deep on the map rather than in the middle of it

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 exploration is filed at the Abyss, the fourth of the site’s five depths, and marked unknown.

Corrected

24 September 2026. Previously: “That is the honest reason this sits at the bottom of the map” The question is filed at the Abyss, not at the Unknown, the deepest level, so it is not at the bottom of the map.

Claim 60 · checked 24 September 2026 · AI-assisted audit

Claim: it is a question about what is underneath the physics, asked from inside, with no instrument that reaches.

Kind: Open question. Something the page says is not known.
Review: Presented as open. The page says this is unresolved, and the review found that it is.

What this does not establish

Bostrom holds that evidence about the first two branches bears on the third (claim 54). That is an inference about the balance of the branches, not an instrument that reaches underneath.

Claim 61 · checked 24 September 2026 · AI-assisted audit

What was read

Are We Living in a Computer Simulation?Bostrom, The Philosophical Quarterly · The author’s copy at simulation-argument.com/simulation.pdf, headed with the Philosophical Quarterly 53 (2003) citation and titled “Are You Living in a Computer Simulation?”; the journal’s typeset pages not readRead in full, 24 September 2026 · Copyright; quoted brieflySuperscript exponents are lost in the extracted text, so excerpts avoid the figures and the equations.
Constraints on the universe as a numerical simulationBeane, Davoudi and Savage, The European Physical Journal A 50 · arXiv:1210.1847v2 (9 November 2012); the published version is The European Physical Journal A 50, article 148 (2014)Read in full, 24 September 2026 · Copyright; quoted briefly
Consciousness in Artificial Intelligence: Insights from the Science of ConsciousnessButlin, Long and others · arXiv:2308.08708v3 (22 August 2023); abstract and section 1.2 read closelyRead in full, 24 September 2026 · CC BY 4.0
The Simulation Argument FAQBostrom, simulation-argument.com, version 2.0 · The Simulation Argument FAQ, version 2.0 (2025), simulation-argument.com/faq/Read in full, 24 September 2026 · Copyright; quoted brieflyEm dashes in the source are recorded as en dashes.
Are You a Sim?Weatherson, The Philosophical Quarterly 53 · The author’s penultimate draft (brian.weatherson.org/sims.pdf), which gives the published citation as Philosophical Quarterly 53 (2003): 425-31Read in full, 24 September 2026 · Copyright; quoted briefly
The Simulation Argument: Reply to WeathersonBostrom, The Philosophical Quarterly 55 · The journal’s pages, Philosophical Quarterly 55 no. 218 (January 2005), pp. 90-97, from simulation-argument.com/weathersonreply.pdfRead in full, 24 September 2026 · Copyright; quoted briefly
On the ‘Simulation Argument’ and Selective ScepticismBirch, Erkenntnis 78 · The Springer online-first pages (Erkenntnis, published online 2012), from simulation-argument.com; printed in Erkenntnis 78 (2013), pp. 95-107Read in full, 24 September 2026 · Copyright; quoted briefly
Astrophysical constraints on the simulation hypothesis for this Universe: why it is (nearly) impossible that we live in a simulationVazza, Frontiers in Physics 13 · Publisher PDF of 10.3389/fphy.2025.1561873 (Frontiers in Physics, open access), located through UnpaywallRead in full, 24 September 2026 · CC BY 4.0Read in full on 2026-09-24, sections 3.3, 4.2 and 5 against the claim; the abstract had been read before.