Week 3 Flashcards
Introduction to the Problem of Disagreement
- Kelly explores whether knowing that an epistemic peer disagrees with you should make you less confident in your belief
- If two equally intelligent and informed people disagree, it seems rational to reduce confidence or suspend belief
- Descriptive disagreement – How does disagreement actually affect beliefs?
Normative disagreement – How should disagreement affect beliefs? - Because the psychological effects of disagreement do not necessarily determine what is rational to do in response.
Epistemic Peers and Peer Disagreement
- epistemic peer - Someone who is roughly equal to you in intelligence, reasoning ability, and access to relevant evidence
- He extends the definition of epistemic peerhood to include not only general epistemic virtues but also equal exposure to relevant arguments and evidence.
- If someone is not an epistemic peer, their disagreement might be dismissed due to ignorance or bias.
- Whether two people truly have the same level of reasoning skill and access to the same evidence
The Equal Weight View (EWV)
- The idea that when two epistemic peers disagree, both should give equal weight to each other’s opinion and suspend judgment
- If two people are equally rational and informed, neither has a reason to favor their own belief over the other’s
- How does EWV relate to the idea of symmetry? - Since both peers are equally rational, neither should privilege their own judgment over the other’s
- Why do some philosophers argue that disagreement should lead to agnosticism - Because if no one has an epistemic advantage, it seems arbitrary to maintain confidence in one’s own belief
Criticisms of the Equal Weight View
- Why does Kelly reject the Equal Weight View - He argues that disagreement does not necessarily undermine the rationality of holding onto one’s belief
- He argues that once disagreement arises, the symmetry is broken—one person must have misjudged the evidence
- How does Kelly compare epistemic disagreement to chess - Even if two players are equally skilled, one can still make a better move in a specific game—similarly, one person in a disagreement might have evaluated the evidence better.
- Why does Kelly argue that rational belief retention is not arbitrary - Because after assessing all the evidence, a person may reasonably conclude that they have judged better than their peer.
The Steadfast View
- The idea that one can rationally retain a belief even when faced with disagreement from an epistemic peer
- He argues that one’s rationality depends on how well they have assessed the evidence, not simply on the fact of disagreement.
- Disagreement does not necessarily demand belief revision, especially if one has thoroughly scrutinized the evidence.
Higher-Order Evidence and Double-Counting
high order evidence - Evidence about how well you or someone else has assessed first-order evidence
- The fact that a reasonable person disagrees with you can be seen as evidence that your belief might be mistaken
- If you already assessed all first-order evidence, treating your peer’s belief as additional evidence may lead to over-weighting that evidence
- Just as an insurance company adjusts risk assessment based on new data, you should only adjust beliefs when disagreement provides genuinely new evidence
Disagreement and Skepticism
- How does disagreement relate to skepticism - Some argue that persistent disagreement should make us skeptical of our ability to form rational beliefs
- What is Kelly’s response to the skeptical argument - He argues that disagreement should not necessarily undermine rational belief, as evaluating evidence correctly is still the key factor
- How does Kelly use philosophy of religion to illustrate his point - Religious disagreement is often cited as a reason for skepticism, but by Kelly’s logic, belief can still be rational even in the face of widespread disagreement.
The Role of Possible vs. Actual Disagreement
- What distinction does Kelly make between actual and possible disagreement - The fact that disagreement exists is not more epistemically significant than the possibility that disagreement could exist
- How does he use Newcomb’s Problem to illustrate this - Even if in one possible world, everyone believes in One-Boxing, that alone does not mean it is rational; the arguments matter more than consensus
- Why does he bring up skepticism about other minds - Although few philosophers are genuine skeptics about other minds, their absence does not refute skepticism—it’s the arguments that matter.
When Does Disagreement Matter?
- Kelly thinks disagreement is ever epistemically significant, but only when it highlights new evidence or arguments that one has not yet considered.
- Disagreement alone is not sufficient to justify skepticism or belief revision—it depends on the strength of the actual evidence
- How does Kelly view rationality in the face of disagreement - It is not irrational to maintain a belief after disagreement, as long as one has thoroughly assessed the evidence.
Introduction to the Epistemology of Disagreement - Christensen
- Christensen explores how we should react when we discover that an epistemic peer disagrees with us on an issue where we have both evaluated the same evidence
Why does Christensen argue that epistemic imperfection is central to the problem of disagreement?
- Because:
- Our evidence is limited—we never have access to the full truth.
- We respond imperfectly to the evidence we do have.
- Rationality requires acknowledging these imperfections when encountering disagreement
Encountering disagreement forces us to:
- Re-evaluate our evidence and reasoning.
- Consider alternative perspectives.
- Recognize cognitive biases
What is the key challenge disagreement poses to rational belief?
- If two equally rational individuals assess the same evidence and reach different conclusions, one must have made a mistake—so how can either justifiably maintain confidence in their own belief?
Epistemic Peers and the Significance of Disagreement - Christensen
- Someone who is equally informed, rational, and capable of evaluating evidence in a particular domain
epistemic peerhood
Equal intelligence and reasoning ability.
- Access to the same evidence.
- No known biases or systematic errors favoring one person over the other.
Equal Weight View (EWV) vs. The Steadfast View - Christensen
What is the Equal Weight View (EWV)?
- The idea that, upon discovering peer disagreement, each person should give equal weight to the other’s opinion and adjust their confidence accordingly.
What is the Steadfast View?
- The view that one can rationally maintain their belief despite peer disagreement, assuming they have no independent reason to distrust their reasoning.
How does Christensen argue against the Steadfast View?
- He claims that failing to adjust beliefs after learning of peer disagreement is irrational because it ignores higher-order evidence (evidence that one might have made a reasoning error).
Rejecting the “Live-and-Let-Live” Attitude - Christensen
What is the “Live-and-Let-Live” attitude in epistemology?
- The view that two people can rationally hold different beliefs based on the same evidence without needing to revise their confidence.
Q: Why does Christensen reject this view?
- If disagreement does not require belief revision, then belief formation becomes arbitrary.
- It fails to acknowledge the possibility of error—if one’s peer is equally rational, why assume that they are the mistaken one?
- It leads to epistemic arrogance, allowing people to ignore conflicting evidence.
How does the doctor case illustrate the problem with the “Live-and-Let-Live” view?
- Two equally qualified doctors examine the same medical data but reach opposite conclusions on the best treatment.
- If they refuse to adjust their confidence, they risk making a deadly mistake.
- This highlights how disagreement should force belief revision, especially in high-stakes situations.
Illustrative Cases of Disagreement - Christensen
What does the restaurant bill case illustrate?
- Two equally skilled people calculate how much each diner owes but arrive at different numbers.
- Since they know they are equally good at mental math, each should reduce confidence in their own answer.
How does the meteorologist case support belief revision?
- Two equally trained meteorologists analyze the same weather data.
- One predicts a 55% chance of rain, while the other predicts 45%.
- If neither has any reason to trust their judgment over the other’s, both should revise their probabilities toward each other.
What does the lottery ticket case demonstrate?
- If a friend checks a lottery ticket and claims they won, while I check and see they lost, I should take their claim seriously rather than dismissing it outright.
- Even though I was initially 99.9999% certain the ticket lost, disagreement is a strong piece of new evidence that should lower my confidence.
Arguments Against the Steadfast View - Christensen
How does Christensen use the concept of higher-order evidence against the Steadfast View?
- First-order evidence = The direct evidence about a claim (e.g., scientific data, logical reasoning).
- Higher-order evidence = Evidence about the quality of our reasoning process (e.g., learning that a peer disagrees with us).
- Disagreement is higher-order evidence that one’s reasoning might be flawed, and ignoring it is irrational.
How does Christensen critique Thomas Kelly’s defense of the Steadfast View?
- Kelly argues that disagreement is not necessarily evidence of error—one person might have evaluated the evidence better.
- Christensen counters that without independent reasons to favor one’s own belief, it is epistemically arrogant to assume one’s peer is wrong.
Why does Christensen reject the idea that belief revision always leads to skepticism?
- Moderate belief revision ≠ full skepticism.
The degree of belief revision depends on:
- The reliability of each person’s reasoning.
- The complexity of the issue.
- The strength of the first-order evidence.
The Role of Justification and Error - Christensen
Why does actual disagreement matter more than possible disagreement?
- We already know that possible disagreement exists in every belief system.
- But actual disagreement provides concrete evidence that someone is wrong.
How does the drugged doctor case illustrate epistemic humility?
- A doctor learns they were unknowingly drugged, impairing their judgment.
- Even if they think they calculated a correct dosage, rationality requires them to seek a second opinion.
- This parallels peer disagreement: learning of a peer’s conflicting belief should cause similar self-doubt.
Final Takeaways on the Epistemology of Disagreement - Christensen
Why is Christensen’s argument not fully skeptical?
- He does not claim that we should always abandon our beliefs when faced with disagreement.
- Instead, he argues that we must factor in disagreement as higher-order evidence when assessing our confidence in a belief.
What is the key insight from Christensen’s paper?
- Disagreement among epistemic peers is a significant epistemic challenge.
- Ignoring disagreement is irrational, but belief revision should be proportional to the strength of the conflicting evidence.
