False Testimony and the Limits of Self Doubt

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Being deceived about what scientists believe does not necessarily make our memory, perception, or judgment generally unreliable. In this paper, I challenge John Pittard’s claim that accepting misleading appearances about cosmology prevents us from reasonably trusting our beliefs about the world. My objection focuses on how he treats deception: even extensive false testimony can give us reason to reject the sources involved without giving us equally strong reason to distrust beliefs supported by other evidence. Using Adam Elga’s comparison of explanations for misleading evidence, I argue that Pittard groups together cases with different consequences and then rules out trusting our beliefs under any of those explanations. His own conspiracy example does not show why we must rule out that possibility.

A Boltzmann brain forms through a random fluctuation rather than ordinary growth and development. Center Indifference is a principle about which observer we should think we are. Suppose a possible universe contains several observers whose evidence is exactly like ours. The principle says that, if that universe is the actual one, we should give each of those observers an equal chance of being us. If nearly all of them are Boltzmann brains, we should then think we are probably Boltzmann brains. For this argument, I accept what the principle says we should believe if that universe is actual. My objection addresses the possibility that our apparent evidence for such a universe is misleading.

Pittard separates a true Boltzmann-brain cosmology, a real but mistaken agreement among scientists, and the false appearance that scientists agree. His premise (7) says that strong confidence in our beliefs about the world requires high confidence in the second option (Pittard, pp. 15–18). I argue that the third option can also leave room for reasonable self-trust. The issue is whether every plausible explanation of the false consensus gives us reason to distrust our other beliefs, not just whether some explanations do.

The key passage is Pittard’s discussion of a conspiracy. He says it would undermine trust in other reports from the “same or similar sources,” then concludes that misleading appearances are incompatible with normal self-trust (Pittard, p. 16). The first claim concerns a particular set of reports; the conclusion concerns our beliefs about the world. Those claims differ. Accepting that a source has deceived me can justify revising all beliefs that depend on it without making my other beliefs generally unreliable. The number of reports I must reject does not establish how many other beliefs depend on them.

Consider a deliberate deception about cosmology. A group invents articles, researcher profiles, and interviews that falsely present a consensus. Anna reads this material through several apparently independent outlets. It describes multiple convincing lines of scientific support, and she accurately remembers reading it. She is seriously mistaken: she accepts an entire false account of what scientists believe. Even so, the deception does not necessarily affect her direct experience of her surroundings, her memories of ordinary activities, or information obtained from unrelated people. She can be badly misinformed about the consensus while remaining broadly capable of learning about the world.

The example does not assume that Anna knows which article is false. She may be uncertain whether the apparent consensus resulted from fabricated interviews, claims falsely credited to researchers, or reporters working together to mislead her. These explanations differ about the source of the deception but agree that she could accurately perceive and remember misleading testimony. We must distinguish whether a report is true from whether Anna accurately sees and remembers it. Seeing that a page makes a claim is not the same as knowing that the claim is true. I can reject what a report says while remaining confident that I read and remember it accurately.

Elga’s “Label scramble” case helps explain why this distinction matters. In one version, an apparent warning about a hallucinogen is better explained by incorrect labeling than by hallucination, given the probabilities Elga assigns in the example (Elga, pp. 8–9). The same experience can therefore give us reason to distrust a message without providing equally strong reason to distrust perception. My application does not assume that false testimony is always more probable than hallucination. It shows that the two explanations have different consequences for other beliefs, even when they explain the same misleading message. We cannot determine those consequences simply by placing both explanations in one category.

Anna should distrust the false reports and reconsider how she checks what people tell her. If she mistook repeated claims for confirmation from separate sources, she should correct that mistake as well. Anna can make these revisions while still trusting her ordinary ability to perceive, remember, and check claims. That trust can include recognizing serious weaknesses in how she judges some sources. It does not require believing that all her conclusions are true. Preserving that trust also involves more than counting the beliefs left unaffected. What matters is whether the deception undermines the abilities and independent evidence through which she can check and correct those conclusions.

Pittard might reply that this preserves too little: being deceived on such a scale must shake Anna’s judgment. It should, especially her judgment about which scientific sources to trust. But a reduction in confidence in that judgment does not establish that her beliefs about the world have become unreliable. Otherwise, any discovery of repeated false information would count as a loss of normal self-trust, even when we correctly recognize the problem and revise our beliefs. Correcting a mistake would then become a reason to distrust our thinking in general. If we distinguish ordinary mistakes from skepticism, we must allow people to reject testimony about one subject while still trusting their ability to assess other claims.

Another part of Pittard’s argument supports this approach. When addressing self-undermining, he allows that misleading appearances may make perception or memory unreliable while leaving reasoning and awareness of our own experiences reliable (Pittard, p. 22). I agree that a problem with one ability does not automatically undermine another. The same consideration applies within his conspiracy example: false testimony does not necessarily undermine our ability to perceive and remember what was said. This is not a contradiction in Pittard’s position, since the cases differ. It does show why accepting that appearances are misleading does not by itself determine which abilities remain trustworthy. He recognizes that some abilities can remain reliable, but does not fully apply that distinction to false testimony.

A more serious reply concerns probability. Anna’s situation is possible, but perhaps a large number of apparently supporting reports makes widespread errors in her perception more probable than invented reports. Pittard considers exceptionally strong apparent scientific support (Pittard, pp. 23–26). I do not claim that a conspiracy focused on cosmology must remain probable given every possible set of evidence. However, we should distinguish two kinds of support: how strongly the reported findings would support the theory, and how well Anna’s evidence establishes that those findings were actually obtained. Invented reports can describe findings that would strongly support the theory if they were real. Making the reported findings sound more convincing does not necessarily make accurately reading false reports less plausible than hallucination. Evidence checking the reports’ origins could change that comparison, but impressive scientific content alone does not settle it.

This identifies a specific problem with the argument. Premise (7) excludes misleading appearances as a way to keep trusting our beliefs more generally. But in the conspiracy case, his reasoning gives us grounds to distrust the testimony involved. We can accept that result while still trusting our ordinary abilities and beliefs based on other evidence. This is a counterexample to the move from source distrust to general distrust, not a proof that Anna’s explanation has the highest probability in every cosmological case. Even if each specific explanation involving deception focused on cosmology is unlikely, those explanations could have a high combined probability. If the evidence instead favors widespread errors, broader doubt is appropriate. Grouping these explanations together does not tell us which response is justified.

Pittard is right that avoiding belief in being a Boltzmann brain does not automatically remove every skeptical concern. My conclusion is that his argument also cannot automatically exclude continued trust in our beliefs once we doubt the apparent consensus. His conspiracy example supports no longer trusting the sources involved, while his response to self-undermining accepts that some abilities can remain reliable even when appearances mislead us. Together with Elga’s comparison of explanations, these points support an approach that considers each belief separately. We should revise beliefs when the likely deception gives us reason to doubt the evidence supporting them. Discovering that testimony is false does not, by itself, show that our perception, memory, and judgment are generally unreliable.

References

Elga, Adam. “Boltzmann Brains and Cognitive Instability.”

Pittard, John. “Advancing the Boltzmann Brain Skeptical Challenge.”